Authors

Abstract

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.

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