فرزاد رجایی

Stress is known to affect many reproductive variables, including gonadotropins and sex steroid levels. Stressors such as crowding can alter the normal function of the ovaries, fallopian tubes, and uterine cycles. In the this study, we investigated the effect of crowding stress on mice oocyte parameters and reproductive organs.

Mice were divided into control, low & high- density crowding stress groups, and kept under stres condition for one month. Superovulation was induced in the mice in all groups by pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG). The mice were sacrificed 15 hours after hCG injection. Grade I and IV oocytes were stained with the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method after collection and evaluation. Ovarian, fallopian tubes and uterine horns tissues were evaluated after staining with hematoxylin and eosin (H&E). Data were analyzed by ANOVA. p-value ≤0.05 was considered significant.

The number of grade I and the size of grades I and IV oocytes in the high-density crowding stress group were significantly decreased compared to those in the control group. The rate of DNA fragmentation of grade I and IV oocytes in the low and high- density crowding stress groups demonstrated a significant increase compared to that in the control group. The number of monolayer primary follicles and the height of the fallopian tube epithelium significantly decreased in the high- density crowding stress group compared to those in the control group (p≤0.05).

Crowding as an environmental stress can affect DNA fragmentation by inducing irregularities in follicular and oocyte development.

Infertility is a disorder that affects about 15% of couples and 50% is related to male. Sperm freezing involves storing semen samples at -196°C in liquid nitrogen. During freezing, due to the induction of apoptosis through oxidative stress, the functional indicators of sperm are damaged and ultimately lead to a decrease in fertility. There have been many studies on the use of freezing environments with complementary antioxidants to limit the damage caused by freezing. In this study, melatonin and curcumin were used in combination as antioxidants in sperm freezing.

This study was conducted in 2022 on the semen of 40 men with normal sperm in Qazvin University of Medical Sciences. To check sperm motility by CASA device, morphology by hematoxylin staining, viability by eosin nigrosine staining, DNA integrity by tunnel kit and MDA measurement by reaction method with thiobarbituric acid and spectrophotometer were used. Data analysis was done using SPSS software (version 25) and ANOVA test, dependent t-test and one-way analysis of variance. P<0.05 was considered statistically significant.

The use of melatonin and curcumin either separately or in combination in the freezing environment had a significant effect on the rate of motility and survival, DNA fragmentation and MDA level (P<0.05).

Adding curcumin and melatonin in combination to the freezing environment will have a positive effect on sperm parameters after freezing.

Introduction Alzheimer disease (AD), known to be a leading cause of dementia that causes heavy social and financial burdens worldwide, characterized by progressive loss of neurons and synaptic connectivity after depositions of amyloid-β (Aβ) protein.AD manifests as an impaired ability to comprehend or use words, poor coordination and gait, and impaired executive functions in the realms of planning, ordering and making judgments. Generally, classification of AD includes familial and sporadic AD. Current therapies for AD patients can only alleviate symptoms, but cannot deter the neural degeneration, thus providing no long-term recovery. Stem cells are undifferentiated cells that have a potential to produce many different cell types in the body. A vast amount of data indicates the potential of stem cell therapy for various neurological diseases. Several studies revealed that neurons and glial cells have successfully been differentiated from various stem cells. Thus, in this article, we review the treatment of Alzheimer disease by various types of stem cells.

Bisphenol A (BPA) is a chemical substance that is used in large amounts to produce polycarbonate plastics and epoxy resins. Exposure to low levels of BPA can lead to a variety of health outcomes. Stem cells are undifferentiated cells with the ability to divide and differentiate into different cell types. It is important to investigate the effects of BPA on stem cells.
 

A comprehensive study was conducted on BPA and its effects on stem cells by searching the keywords including Stem cells, Bisphenol A, Obesity in the medical valid databases, mainly PubMed. Among the collected papers, articles that are the most relevant to the purposes of writing this article were selected and studied.

It seems that BPA increases autophagy induction in stem cells and also stimulates stem cell differentiation into adipocytes.

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system which is accompanied by demyelination of the nerves, axonal loss, and disability. The availability of multiple diseasemodifying medications with regulatory approval to treat multiple sclerosis illustrates the substantial progress made in treating the disease. However, these drugs are only partially effective in preventing inflammatory tissue damage in the central nervous system and none of them directly promotes repair. The current treatments for MS largely comprise medications that are either immunomodulatory or immunosuppressive and are aimed at reducing the frequency and intensity of relapses. Recent studies have shown that cellular therapies are capable of repairing CNS neurons and can prevent inflammatory damage caused by the disease. 

A comprehensive review study was performed on MS, the etiologies, and treatmentmethods using the keywords including Stem Cells, Multiple Sclerosis, and Oligodendrocyte in valid medical databases, mainly PubMed. Among the collected papers, articles that were most relevant to the purposes of the study were selected and studied.

Cell therapy is considered a promising potential treatment for multiple sclerosis, perhaps particularly for the progressive form of the disease for which there is currently no useful treatment. Stem cells can be differentiated into nerve cells, including oligodendrocytes, in the patient’s body and help repair neuronal myelin. Thus, in the present article, we reviewed a variety of cellular resources and their characteristics for
the treatment of MS.

Parkinson's disease (PD) is a prevalent movement disorder in elderly with progressive motor complications due to antioxidant defense system deficiency and accumulation of degraded proteins in dopaminergic neurons of midbrain. Ginkgolide is biologically active terpenic lactones as a polyphenol, with potent antioxidant and anti-inflammatory properties. The present study aimed to evaluate the neuroprotective effects of Ginkgolide in 6-hydroxydopamine (6-OHDA) rat model of PD. Intrastriatal 6-OHDA-parkinson’s disease rat model was pretreated with Ginkgolide at 50 mg/kg/day for 4 weeks. Apomorphine-induced rotation test was applied to evaluate the neuroprotective effects of Ginkgolide. In addition, the antioxidant effects of Ginkgolide were assessed by analyzing the levels of thiobarbituric acid reactive substances (TBARS), Glutathione-S-transferase (GST), reactive oxygen species (ROS) homovanillic acid (HVA), and dopamine (DA). Ginkgolide pretreatment led to reduced nigral and striatal TBARS, and ROS and increased the levels of GST, HVA, and DA. Meanwhile, Ginkgolide attenuates apomorphine-induced rotational bias and reduced contra-lateral rotation in Ginkgolide treatment group. These findings indicated the neuroprotective potential of Ginkgolide in 6- OHDA rat model of PD via amelioration of oxidative stress.

Stem cells are undifferentiated cells with the ability to divide and differentiate into distinct cell types. The source of these cells is from embryos and adults, that each cell has its own specific characteristics. For nearly decades, experimental studies have been conducted to use these types of cells to treat various diseases. Parkinson's disease is one of the most common neurodegenerative diseases, resulting in a deficiency of dopaminergic neurons. Therefore, we study the role of stem cell therapies in the treatment of Parkinson's disease. Initially, 73 relevant articles selected from valid databases such as ISC, SID, Google Scholar and PubMed and the role of each type of stem cell in the treatment of Parkinson's disease was collected. Stem cells can be used in experimental studies regard to the unique characteristics and using different laboratory agents for any particular type of cells. Stem cells can provide an unlimited source of dopaminergic neurons for transplantation and improve motor behavior and symptoms of Parkinson's disease Study and comparison of different types of stem cells refer to the more effective role of neural and umbilical stem cells in treating Parkinson's disease.

Pancreatic cancer is one the most malignant cancers in human. A great percentage of patients die annually due to lack of early detection as well as efficient treatment strategies. Only five-year survival rate is still only seen in 5% of patients. Major problem of this deadly disease is the intrinsic and acquired resistance to current chemotherapeutic agents such as gemcitabine. So far, different molecular mechanisms are attributed to gemcitabine resistance. For instance, genetic mechanisms, aberrant gene expression in cellular signaling pathways, cancer stem cells, impaired apoptosis related genes, epigenetic changes and potential role of microRNAs have been identified in gemcitabine resistance of pancreatic cancer. Improving the drug efficacy and overcoming to drug resistance is the current goal in treatment of pancreatic cancer. Understanding the cellular and molecular mechanisms of resistance can help us to develop novel therapeutic approaches leading to increased effectiveness of current treatments. In this review, we summarized the molecular mechanisms involved in gemcitabine resistance in pancreatic cancer.

Deficit of inhibitory GABAergic neurons as a part of central nervous system (CNS) pathogenesis was reported in neurodegenerative disorders; and adipose-derived stem cells (ADSCs) were shown to be a feasible option for cell transdifferentiation in neuronal disorders therapy. In this study, ADSCs transdifferentiated into GABAergic-like neurons (GLNs).
Under sterile conditions ADSCs were obtained from pararenal fat of 2 male adult rats. Following third passages of cell culture, ADSCs were preinduced to neural-like cells (NLCs) using 1mM β-mercaptoethanol (βME) and 10µM retinoic acid (RA), and then NLCs were induced by creatine(Cr) in 1, 5, 10, 20 millimolar for 5 days. In induction stage, the effects of creatine on differentiation were studied by anti nestin and GABA antibody immunostainig. The roles of GABARAP, LC3 and p62 autophagy genes in transdifferentiation were assessed by RT-PCR.
FINDINGS: Immunocytochemical studies on ADSCs using CD49d indicated that cultured cells were ADSCs. Preinduction stage results showed that 10µM RA after 2 days, has the best effect on differentiating the ADSCs to NLCs. Immunostaining after induction stage showed high percentage of neural and GABAergic markers (GABA) using 10 mMol creatine after 5 days. ADSCs expressed p62 gene, however, preinduced cells expressed LC3 and GABARAP autophagy genes as well.
In the present study, we demonstrated that ADSCs can be efficiently transdifferentiated into NLCs using βME (1mM) and RA (10µM). Moreover, these NLCs induced by 10mM creatine for 5 days and differentiated into GLNs expressing nestin and GABA neural markers. GABARAP, LC3 and p62 autophagy genes expressed by preinduced cells indicating autophagy might have a role in the transdifferentiation of ADSCs into NLCs

Investigating effects of stress in animal models may suggest clinical treatments or prevention protocols for effects of stress in humans. The aim of this study was to determine the histological effects of chronic multiple stress on rat ovary. This experimental study was conducted in 18 adult female Wistar rats that were randomly divided into two equal groups in Qazvin University of Medical Sciences during 2014. The mice were exposed to different stress including food deprivation, water deprivation, immobility at 4 º c, forced swimming, and isolation for 10 days in the under stress group while the mice in the control group were kept in their cages without any intervention. After the intervention period, the mice were anesthesized, the ovary of the animals were removed and weighed, and the ovary samples were prepared for light microscopic study. The number and diameter of corpus luteum, and the number of antral and preantral follicles were determined using Image Tool software. Data were analyzed using T-test. The mean number and diameter of corpus luteum significantly reduced in the under stress group compared to the control group. The mean number of antral and preantral follicles significantly reduced in the under stress group compared to the control group. With regards to the results, it seems that chronic multiple stress can have negative effects on rat ovary by reducing the diameter and number of corpus luteum and the number of antral and preantral follicles.

Today, due to the modern industrial life of human beings, stress has become prevalent among them and they will suffer from its complications. Exposure to stress during pregnancy can change many babie's normal physiological processes. The separate and combined effects of three common types of prenatal stress were investigated on motor learning of male offspring of rats. In the present study, pregnant NMRI rats were used. Except the control group, the other groups were stressed on the eighth day of gestation for 10 days. The motor learning of 40 male offspring rats were tested using the rotarod performance test 75 days after the experiment. The length of time that each rat could maintain its balance was recorded automatically. The study groups included control, electromagnetic field stress (intensity 1.2 mT, 50 Hz), immobility stress (for 0.5 hour - 2 times/day), social stress (6 rats kept in a small cage), and combined stress (all 3 of the above stresses). Data were analyzed by using multiple comparisons and Tukey’s tests. The motor balance of the combined stress group was lower than the control, at first timing of the first test day (P < 0.05). In the next few days of the test, the effects of stress on learning of experimental groups were not similar. Combined stress reduced motor learning. Learning fluctuations were higher in electromagnetic field stress group compared to the other groups. The results of our study showed that prenatal combined stress can reduce motor learning of children.

In patients with infertility, to obtain multiple oocytes in a cycle, ovulation-stimulating drugs areused to increase the chance of pregnancy. This study was conducted with the purpose of determining the effect ofovarian induction on the growth of ovarian follicles and corpus luteum in NMRI mice. In this study, 40 6-week-old female mice of NMRI strain were selected and divided into four groups of 10.The control group received normal saline, 7 IU of PMSG was injected to thesecond group, 10 IU to the third group, and 12 IU to the fourth group. Fourty-eight hours later, hCGwas injected with the same dose of PMSG. Twenty-four hours after injection of hCG, the mice were killed by cervical dislocation and their ovaries were removed. Then, after staining and slide preparation, the size of ovaries, number and size of corpus luteum and ovarian follicles was analyzed using statistical tests, such as Kolmogorov–Smirnov, analysis of variance, and, Kruskal-Wallisat the significance level of less than 0.05. In this study,ovulation induction with PMSG and hCG hormonescaused changes insize and number ofovarianfollicles, ovary, and corpus luteum. The results of the presentstudy revealed that ovulation hormones with PMSG and hCG hormones can increasethe number of primary multilayer follicles, but decrease the size of graafian follicles and corpus luteum.

Recurrent pregnancy loss (RPL) is a multifactorial disorder. Environmental factors and genetics can affect pregnancy outcomes.

Conflicting data suggest an association between estrogen receptor alpha (ESR1) gene polymorphisms and RPL. In this study, such association was investigated in Iranian women with RPL.

In this case control study, blood samples were collected from 244 women with a history of three or more consecutive pregnancy losses and 104 healthy women with at least two live births. Using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP), we studied -397C/T and -351A/G polymorphisms on ESR1 gene in case and control subjects.

The genotypic frequencies of -397C/T and -351A/G polymorphisms on ESR1were not significantly different between RPL and control groups (p=0.20 and p=0.09, respectively). A significantly negative correlation was observed between -397C/T and -351A/G (r=-0.852, p<0.001) in RPL women and complete linkage disequilibrium between the investigated polymorphisms was found (D’: 0.959; r-square= 0.758, p<0.001).

This investigation suggests that the analyzed polymorphisms on ESR1gene are not associated with an increased risk of RPL in the studied population.

Regarding to remarkable growth of population and consequent crowding of it in big cities and immune system sensitivity against environmental agents، the present study aimed to investigate the effects of social stress on spleen of mouse. Methods and Materials: Thirty adult male mice of the NMRI strain were selected at the age of 5-6 weeks and were randomly divided into 2 groups. In control group، 5 animals per cage (3 cages) and in stress group، 15 animals per cage were housed for a period of two months. All animals were anesthetized with an intrapritoneally injection of ketamine and xylazine after two months. The sample of blood from left ventricle of heart was provided by heparinized syringe. Serum samples were used for hormonal study by radioimmunoassay. Spleen was weighted after removing and the samples of spleen were fixed for light microscopic study. The mean numbers of macrophage and megakaryocyte cells were determined. The data has been compared using statistical methods (t-test and Mann-Whitney test). The mean weight of spleen and corticosterone level of serum was insignificantly reduced in stress group compared to control group. The mean numbers of macrophage cells in stress group were insignificantly increased compared to control group. The results showed that the mean numbers of megakaryocyte cells were significantly reduced between stress and control group (P=0. 007). The results showed that the crowding stress can be resulted in decreased number of megakaryocyte cells whereas no significant effect on macrophage cells، serum cortisol hormone level and weight of spleen were found. However، further studies in this area are needed to confirm it.

The male factor contributes to more than 50% of the infertility cases. Studies have shown that a variety of mechanisms are involved in male infertility، though a few of them have been identified till now. The aim of this study was to evaluate the testicular histopathology of men with non-obstructive azoospermia referred to infertility center of Shariati hospital. This experimental study was conducted on 50 testicular tissue samples of men with non-obstructive azoospermia who were candidates for assisted reproductive procedures referred to Shariati hospital in 2012. Paraffin blocks were prepared from the testicular tissue biopsy and the sections were stained in hematoxylin and eosin. 16% of the samples were classified as hypospermatogenesis; 48% were classified as spermatocytic arrest; 18% were classified as Sertoli cell only; and 18 % were classified as tubular fibrosis. With regards to the results، future studies would focus on reasons of germ cell cycle arrest in men with non-obstructive azoospermia and setting up the related diagnostic genetic tests.

The application of herbal plants instead of synthetic drugs is increasing in recent years because of their lower side-effects and high varieties of efficient components. The aim of the present study was to evaluate the antinociceptive effects of hydroalcholic extract of grape seed using hot plate and formalin test. This experimental study has been done on 56 NMRI male mice (28±3 g) (n = 7 in each group) in weight. The hot plate and formalin test were used for acute and chronic pain. After preparation of extract، to evaluate the effect of pain related behaviors on antinociception، animals systemically received grape seed extract (75، 150، 300، mg/kg) and after 30 min pain related behaviour was monitored in formalin and for hotplate tests. The data was analyzed using SPSS software and ANOVA at significance level p < 0/05. The results showed that hydroalcholic Grape seed extract (75، 150، 300، mg/kg)، significantly can induce antinociception in both phases of formalin test. Also، the Grape seed extract caused delay in painful behaviours (licking and jumping) in hot-plate test. The present results show that hydroalcoholic extract of grape seed has analgesic properties in response to acute and chronic pain in the formalin with hot plate tests and can be substituted for chemical analgesic drugs.

With regard to wide spectrum application of microwave in human life، its biological effects on tissues are still under debate. The aim of this study was t o determine the effects of 950 MHz microwave radiation on morphometric changes of prostate in rabbit. In this experimental study، 18 New Zealand male rabbits (11-13 weeks old) were randomly divided into control، 3 W and 6 W groups in Qazvin University of Medical Sciences in 2012. The rabbits in the experimental groups were exposed to simulated 950 MHz and 3 or 6 W microwave radiation 2 hours a day for 2 weeks. After one week rest، the rabbits were sacrificed using anesthetic drugs and the prostate tissue samples were prepared. After preparing microscopic slides، villous height، villous thickness and muscle layer thickness were measured. Data were analyzed using ANOVA and Tukey’s test. The villous height was significantly decreased in the 3 W group compared to the control and 6 W groups while it was significantly increased in the 6 W group compared to the control group. The villous thickness was increased in both experimental groups compared to the control group but the difference was statistically significant for 6 W group. Increased villous thickness was not different between the experimental groups. The muscle layer thickness was significantly increased in both experimental groups compared to the control group. With regards to the results، it seems that the microwave radiation with 950 MHz frequency has negative effects on morphometric changes of prostate in rabbit.

The use of medicinal plants due to their lower side effects and the various efficient components has been increased in recent years. The aim of this study was to evaluate the antinociceptive effect of hydroalcoholic extract of green tea in male mice using the hot plate and formalin tests. In this experimental study، 56 NMRI male mice (weight، 28±3 g) were assigned to the control and experimental groups. The experimental group received the green tea extract (75، 150 and 300 mg/kg) and 30 min after the injection، the hot plate and formalin tests were used to assess the acute and chronic pain. Results showed that hydroalcoholic extract of green tea (75mg/kg) could induce antinociception in phase 2، not in phase 1 and interphase of the formalin test. Hydroalcoholic extract of green tea (150 and 300 mg/kg) could also induce antinociception in phase 1، interphase and phase 2 of the formalin test. Moreover، hydroalcoholic extract of green tea caused a delay on the painful behaviors in hot-plate test. Hydroalcoholic extract of green tea has analgesic properties and can be used as a substitute for chemical analgesic drugs.

The increase of stress following technology development appears to be a threat to human body organs such as nervous system. The present study was conducted aiming at investigating the effects of chronic multiple stress on morphometric changes of Betz cells in male rat cerebral cortex. In this experimental study, 18 Wistar rats were randomly divided into two equal groups. Animals of the under stress group for 10 days were exposed to different stresses, such as food deprivation, water deprivation, forced swimming, immobilization at 4°C, and isolation, while the animals in control group were kept in their cages without any intervention. After the intended period, the animals were anesthetized and then their brains were removed. After fixation, samples of frontal cortex of the brain were prepared for light microscopy study. The data analysis were performed using t-test, and the significance level was considered p<0.05. The mean number and size of Betz cells in the stress groups was significantly lower compared to control group (p<0.001). The qualitative observations also showed chromatolysis of nissl bodies, nucleus condensation, and decrease of neural processes. The results of the present study showed that chronic multiple stress can have negative effects on the rat cortical internal pyramidal layer through reducing the size and number of Betz cells; however, more studies are needed to confirm the above results.

Given the wide range of microwave applications in human life، their effects on biological tissues are still controversial. The aim of this study was to determine the effects of 950 MHz cell phone microwave radiation on morphometric changes of testis in rabbit. In this experimental study، 18 New Zealand male rabbits were randomly divided into control، 3 W and 6 W groups. Unlike the control group، the experimental groups were exposed to simulated 950 MHz and 3 or 6 W microwave radiation 2 hours a day for 2 weeks. After one week rest، the animals were sacrificed using anesthesia and microscopic slides were prepared from their testis. The seminiferous tubular diameter and spermatogonia، spermatocyte، spermatid and sperm counts were determined. Data were analyzed using ANOVA and Kruskal Wallis. The number of spermatogonia cells in the 6 W group was decreased significantly compared to the control group and the 3 W group. There were no significant differences between the 3 W group and the control group in terms of the spermatogonia cell count. Spermatocyte cell count and spermatid cell count were found to be significantly different between 3 groups. Sperm count was significantly different between the 6 W group and the control group. With regards to the results، it seems that the microwave radiation with 950 MHz frequency can lead to detrimental effects on rabbit spermatogenesis by changing the number of spermatogenetic cell line.

There are different kinds of stress on mothers during prenatal period. The present study investigated the effects of exposure to chronic heterogeneous sequential stress during prenatal period on formalin-induced nociceptive behavior in adult offspring. In the present study، animals were divided in stressed and non-stressed groups and their offspring divided in male and female groups. Heterogeneous sequential stress including food deprivation، water deprivation، restraint، restraint at room temperature، restraint at 4◦C، forced swimming and social isolation were applied during days 9 to 19 of gestation. Formalin test as chemical model and hot-plate as thermal pain model were used in rats. Chronic heterogeneous sequential stress increased the nociceptive behaviors in male rats in first part and in female rats in second part of phase 2 of formalin test compared with controls. The result of this study showed that chronic heterogeneous sequential stress in rats increased the nociceptive behaviours in second phase of formalin test in a gender-dependent order; which suggested chronic heterogeneous sequential stress may be useful in evaluating the basic mechanism of exposure to chronic heterogeneous sequential stress during prenatal period on in adult offspring.

Dexamethasone is a widely use glucocorticoid and its prescription has been increased during the recent years. In the present study the effects of dexamethasone on the reproductive system of male mice was investigated. In this experimental study، 50 adult male NMRI mice were randomly divided into five groups as experimental، sham and control. Experimental groups were given dexamethasone at a dose of 4 mg/ kg، 7 mg/ kg and 10 mg/ kg respectively by intraperitoneally injection on 7 consecutive days. Sham group was injected with saline while control group received nothing. One day after the last injection، all animals were anesthetized. The mice and their testes were weighed. After preparation of microscopic slides، height of the epididymis and deferens epithelium was determined using Image tool software. The data were analyzed statistically using ANOVA and Scheffe test. The mean height of epididymis and deferens duct epithelium in experimental groups significantly decreased compared to sham and control group (p=0. 001). Meanwhile، the severity of this reduction was dose-dependent and in 7 mg/ kg group was significantly reduced. Although، the mean testicular weight of mice in experimental groups showed no significant differences compared to control group the mean weight of animals only in 7 mg/ kg group significantly decreased compared to sham and control group (p=0. 042). The present study indicated that repeated injections of dexamethasone resulted in detrimental effects on the reproductive system by numerous changes in the epididymis and deferens duct and fertility of male mice consequently.

The increase of stress following the technological improvements appears to be an important factor that causes organs disorders like genital system. Therefore the present study was conducted to investigate the effects of chronic multiple sequential stress on rat testis 18 Wistar rats were divided randomly into two equal groups. In animals under stress، the mice were exposed to different multiple sequential stress as Forced swimming، Restraint، Water deprivation، Isolation and Food deprivation for 10 days while the animals in control group were kept in their cages without any disorders. After weighing the animals and anesthesing with xylazine-Ketamine، the testis of animals were removed and weighed. After fixation with formaldehyde (10%)، testis samples were prepared for light microscopic study. The number of spermatogonia، spermatocytes I & II، sperm & leydig cells، thickness of the seminiferous tubule determined using Image Tool software in the studied groups. Finally the data were compared statistically. The present study showed that the mean number of spermatogonia، spermatocyte I & II، sperm & leydig cells in stress group have significantly decreased compared to control group (P<0. 001). Moreover، the mean thickness of seminiferous tubule in stress group have significantly decreased compared to control group (P<0. 001) Our study showed that chronic multiple sequential stress can have negative effects by reducing the number of spermatogonia، spermatocyte I & II، sperm، leydig cells & thickness of seminiferous tubule in rat testis but more studies are needed to confirm these results.

Oocyte cryopreservation is one of the most important topics in the field of assisted reproductive technology to preserve women fertility, but relationship between cryopreservation and apoptosis is still a matter of debate. The present study was aimed to investigate the effects of vitrification on apoptosis in mouse oocytes by Cryotop method. A total of 200 germinal vesicle (GV) and 200 metaphase II (MII) oocytes were obtained from ovaries and fallopian tubes of NMRI mice, respectively and divided into control and experimental groups. Oocytes in experimental group were vitrified by Cryotop using vitrification medium and were kept in liquid nitrogen for one month. The survival rate of oocytes was evaluated after 2 hour incubation time. Then, the oocyte apoptosis was evaluated by TUNEL technique and compared with those in control group. The data was compared statistically using SPSS software and chi-square test. The survival rates of vitrified GV (93%) and MII oocytes (88%) showed a significant decrease compared with the control group (P<0.05), but there was no significant difference in survival rate of both vitrified oocyte groups. The incidence of apoptosis in vitrified and control GV oocytes showed no significant difference (13% vs. 7%), but the rate of apoptosis in vitrified MII oocytes increased significantly not only in comparison with MII control group (25% vs. 5%) but also with vitrified GV oocytes (P<0.05). The results indicate that vitrification increases apoptosis in mouse MII oocytes and apoptosis may play a role in MII oocyte injury after vitrification.