جستجوی مقالات مرتبط با کلیدواژه « سلول های بنیادی اسپرماتوگونی » در نشریات گروه « کشاورزی »

If spermatogonial stem cells (SSCs) are transplanted into the testicles of lambs that do not have this type of cell, they begin to produce sperm in the testis of the recipient rams. The aim of this study was to prepare recipient lambs. For this purpose, heat treatments of 35, 45, 55 and 65 °C or water-ice treatment for 20, 40 and 60 minutes were used for three replicates with two days interval. The results showed that the condition of the testicles was normal at 45 °C, but the treatment at 55 °C caused infection in the seminiferous tubules and at 65 °C, the testicles were completely destroyed. The use of water-ice treatments did not change the appearance of the testes. Colony formation after extraction and culture of SSCs at 45 °C treatment and water-ice treatments were significantly reduced compared to the control (P <0.05). Also, the expression of c-myc, plzfand gfrl genes as specific SSC markers was significantly reduced in 45 °C and cold treatments compared with the control (P <0.05). Accordingly, for reducing the number of SSCs in lambs’ testicles, water ice or 45 °C treatments for 20 minutes can be used three times at intervals of two days.

Spermatogonial stem cells (SSCs) are a self-renewing population of adult stem cells. These cells could restors reproduction throughout the life of the male by sperm production. In non-primate mammals, spermatogonial stem cells named A-single (As), and the A-paired (Apr) and A-aligned (Aal) are the progenitor spermatogonial population. In human, very little findings is available about SSCs. there are two different types of A spermatogonia, the Adark and Apale spermatogonia. The Adark spermatogonia were referred to as the reserve stem cells, whereas the Apale were considered the renewing stem cells. Regulation of the SSC population includes establishment and maintenance of a niche microenvironment in the seminiferous tubules of the testis. Signaling from somatic cells within the niche determines the fate of SSCs by either supporting self-renewal or initiating differentiation to spermatozoa. Although numerous expression markers have been helpful in isolating and enriching spermatogonial stem cells, no specific marker for this cell type has yet been identified. Culture of testicular cells on various feeder cells has made it possible to culture and expansion of spermatogonial stem cells for a long period of time and hormones and growth factors are investigated for their role in the process of proliferation of spermatogonial stem cells.

The Spermatogonial Stem Cells (SSCs) are founder of spermatogenesis and they are the only stem cells that can transmit genetic materials to offspring’s. This research was conducted to achieving a reliable origin of SSCs from the goat testicular tissues according to a four steps procedure; a) Collection and preparing testicular tissues، b) Two enzymatic digestions، c) Using mesh and cell suspension and d) Culture the isolated SSCs on goat embryonic fibroblasts. ِDistinct markers of pluripotency such as NANOG، SOX2and OCT4 were expressed in the isolated SSCs and also in these cells، nonspecific alkaline phosphatase test was positive. These cells used for co-culturing with GEF for several passages without differentiation or changing the shape. It was also found out that by using DMSO، these cells can be held in -70°C for one month. The result showed that the used procedure was efficient and the cells not only can express distinct markers of pluripotency but also can be culture and proliferate for long period of time without differentiations.

The fate of mouse spermatogonia stem cells’ (SSCs) regulation is controlled by the interplay of signaling networks that either promote self- renewal or induce differentiation. It has been proven that cytokines, growth factors and feeder layers are capable of inducing self- renewal or reducing apoptosis in SSCs, suggesting that the self- renewal signaling pathways and maintenance of cells are promoted by other such triggers as the chemical or physical properties of the Extracellular Matrix (ECM). To investigate the issues, a synthetic polyamide matrix (ultra–web) whose nanofibrillar organization resembles the ECM/basement membrane was employed. Testis cells harvested from the NMRI mouse were cultured on either a nanofiber or a non-nanofiber surface for 10 days. GDNF, bFGF and EGF were taken into account as growth factors. Several tests were conducted on the7th and 10th days past of the culture. Colony assay revealed a higher colony number as well as higher cell number/colony on the nanofiber surface on day 10. Such SSCs markers as? 6, c-kit,? 1, thy-1, OCT-4 and Plzf were also detected using immunoflourecent staining. Reverse Transcription-PCR test revealed the expression of such genes as GFR?-1,Stra8, Vasa,? 6,? 1, thy-1 and OCT-4 for SSCs on the nanofiber and the non-nanofiber surfaces. For functional evaluation, the single cells’ suspension from SSCs colony were microinjected into seminiferous tubules of infertile recipients. Donor germ cells from both groups (nanofiber and non- nanofiber surfaces) were present in the recipient testis. Results indicated that the growth of SSCs on this nanofibrillar surface greatly enhanced proliferation, self- renewal and maintenance in comparison with growth on the non-nanofiber culture surface, despite the presence of growth factors in either of the systems. Thereby it being concluded that a nanofiber surface can provide a suitable microenvironment for SSCs in an in vitro culture system.