The Effect of Aerobic Training and Stem Cells on Gene Expression of Azoospermia Factor in Infertile Rats

Infertility is defined as the inability of couples to conceive after one year of trying to conceive, which is estimated to affect 15% of couples worldwide (1). More than half of infertility cases are male (2). Azoospermia is one of the most important factors in male infertility (7). Y chromosome deletions are one of the main genetic causes of infertility, which have been reported with a frequency of 10-15% in people with severe azoospermia and oligospermia. It is said that fertility genes are located on the Y chromosome and their absence causes infertility, and this hypothesis was later called azoospermia factor (AZFa) (8). Deletion of AZFa is associated with the complete absence of reproductive cells and Sertoli cell syndrome. Deletion of the AZF region causes special phenotypes and genes in each region are in a special stage of cell differentiation they act reproductively (10).Recently, new guidelines for male infertility suggest that lifestyle management, including exercise, should be offered (5). Studies show that exercise can improve sperm parameters (12) and live birth outcomes (13) in male infertility. However, in Wise et al. (2011) research, it was reported that regular exercise does not affect semen parameters. In this prospective study on men, it was shown that none of the seminal parameters changed with regular exercise (15). In addition to lifestyle modification, stem cell therapy appears to be a promising treatment for infertility (16). Spermatogonial stem cells exist in all species, which maintain spermatogenesis throughout the life of a man (18). In this regard, Nasimi et al. (2018) in a study evaluated the effect of stem cell factor on the proliferation and differentiation of spermatogonial cells in the seminiferous tubules of the adult rat testis of the obstructive azoospermia model using a tissue culture system. The results showed that the stem cell increases the number of spermatogonia, spermatocytes and Leydig cells as well as the number of spermatid cells in the testicular tissue of obstructive azoospermia (19).Environment and lifestyle can be an explanation for infertility. Consequently, it is important to focus on modifiable risk factors in this population. A better understanding of changes in the origin of the disorder in response to environmental conditions should also be a way to manage infertility. Therefore, it is necessary to identify appropriate treatment interventions for infertility. As mentioned, a significant improvement in the process of spermatogenesis and tissue indices of the testis has been observed in the samples treated with the culture medium derived from stem cells. In addition, the benefits of physical activity for the treatment of infertility diseases are known. However, the effect of exercise and stem cells on the expression of genes involved in infertility in azoospermia is not clear. Therefore, according to the mentioned cases, the current research seeks to answer the question of whether eight weeks of aerobic exercise and stem cells have aerobic training and stem cells on gene expression of azoospermia factor in infertile rats?

In this experimental study, 25 rats (age 6 to 8 weeks) after creating the azoospermia model were divided into five groups include healthy control, azoospermia, azoospermia-aerobic exercise, azoospermia-stem cells and azoospermia-aerobic exercise-stem cells. The azoospermia model was injected intraperitoneally with busulfan at a dose of 40 mg per rat. Stem cells were transplanted in the vas deferens at the rate of one million cells per rat. The rats after healing the cell transplant wound performed low-intensity swimming exercises for 30 minutes daily, 5 days a week for 8 weeks. Azoospermia gene expression (AZFa) of testicular tissue was measured by Real Time PCR. Data were analyzed by one-way analysis of variance and Tukey post hoc test at the P<0.05.

A significant increase in AZFα gene expression was observed in the azoospermic group compared to the healthy control group (P=0.001). The gene expression of AZFα in aerobic exercise groups, stem cells and combination were significantly reduced compared to azoospermia group (P=0.001). The results showed that the gene expression of AZFα in the combination group was significantly reduced compared to the aerobic exercise groups and stem cells (P=0.001).

The results of the present study show that by inducing the azoospermia model, the expression of the AZFa gene in the testicular tissue of rats increased significantly compared to the control group. Aerobic exercise, stem cells and combined exercise led to the decrease of AZFa gene expression in testicular tissue of azoospermic rats. The results of the current research are in line with the research of Nikbin et al. (2020) and Santos et al. (2015) (23,24). It can be concluded that exercise can help to improve spermatogenesis in groups treated with exercise, probably through the reduction of AZFa gene expression in testicular tissue. Several mechanisms have been studied to destroy the function of the H-P-G axis, including peripheral (inability to synthesize steroids in the testis) and central (change in the central stimulation of the gonads) mechanisms. In addition, other factors that are related to exercise, such as weight and body fat loss, insufficient calorie intake, increased temperature inside the scrotum, and microdamages of the testis are other mechanisms of spermatogenesis reduction (28).On the other hand, nowadays, stem cells have been identified in different parts of the male and female reproductive system, which are part of adult stem cells, and many of these cells have the ability to differentiate and regenerate tissue. (29). The results of the present research are consistent with the research of Nasimi et al. (2018), Salem et al. (2017), Mozafar et al. Several factors play a role in regulating the properties of stem cells. In addition to the role that the microenvironment plays in terms of its three-dimensional engineering structure, the interactions between stem cells and the surrounding environment are also important. These interactions include the communication of stem cells with each other, with adjacent differentiated cells, or with binding molecules in the microenvironment. In addition, the characteristics of the extracellular matrix components, the presence of specific growth factors and various cytokines, as well as the physico-chemical characteristics of the environment (pH, ion concentration, and the presence of metabolites such as ATP) also control the behavior of stem cells (34). . The results of the present study showed that the combination of aerobic exercise and stem cells had a significant effect on the AZFa gene in the testicular tissue of azoospermia model rats, so that the expression of the AZFa gene in the testicular tissue in the combined group compared to the aerobic exercise and cell groups Therefore, it is possible that exercise in combination with cell therapy by regulating the expression of genes involved in infertility in the testicular tissue of busulfan-induced azoospermia model rats exerts its protective effect and in this way It causes fertilization of azoospermia model rats. There were also limitations in the present research, among which we can point out the small number of samples in the present research, therefore, a similar study with the measurement of these indicators in a high number of samples is suggested. In general, it is possible that the therapeutic interventions of aerobic exercise and stem cells can help to reduce infertility, however, more studies will be necessary to clarify the definitive results in this field.The results of the present study showed that azoospermia caused a significant increase in the expression of the azoospermia factor gene, and the intervention of aerobic exercise and stem cells led to a decrease in the expression of the azoospermia infertility gene of the testicular tissue factor. Therefore, according to the results of this research, it is possible that aerobic exercise to stem cells can help to improve infertility in azoospermic samples.