설치류에서 정소조직의 체외배양을 통한 정자형성과정에 관한 연구

Abstract

Spermatogenesis is a complex developmental process of continuous cell division involving a phase of germ cell expansion, meiotic division and cytodifferentiation that ultimately generates mature gametes. The object of this study was the development of optimal culture system in order to induce spermatogenesis in vitro and for its establishment. We collected immature testicular tissues from different developmental-stage of mice and rats which were subsequently cultured on the agarose gel with serum-free culture media. After appropriate culture period, we counted multiple layered seminiferous tubules in the cultured testis tissue to find out whether any differentiation occured following spermatogenesis. Between our experimental mouse strains ICR and C57, as a result, we observed significant increased spermatogenic tubules in case of C57 mouse strain in neonatal stage. In our optimized culture condition, we detected the lectin PNA positive spermatid resulted from spermatogenesis in cultured testis tissue after 6 weeks of incubation. We also injected the lentiviral transduced rat spermatogonial stem cells (SSCs) into recipient testis to generate the transgenic gametes. The testicular fragments were then cultured based on our optimized culture condition. After culturing 8 weeks, we observed expression of GFP in differentiated germ cells including post meiotic germ cells, which suggested the induction of donor-derived spermatogenesis. Also, in order to optimize the in vitro culture system for rat testis, we have tested the additional effect of hormones and growth factors, but could not observe the significant increased effect of hormone and growth factors treated groups than the control. In conclusion, our in vitro tissue culture methods could be applicable for production of in vitro transgenic gametes in various kinds of mammalian species including domestic animal.