Regulatory effect of GDNF on the proliferation and differentiation of mammalian spermatogonial stem cells / 中华男科学杂志

The glial cell-derived neurotrophic factor (GDNF) is a member of the transforming growth factor beta (Tgf-beta) superfamily, which is produced by Sertoli cells and plays an important role in the proliferation and differentiation of spermatogonial stem cells (SSC). The addition of proper amount of GDNF to the culture media can promote SSC proliferation in vitro. Besides, GDNF regulates the self-renewal and differentiation of SSCs through various signaling pathways. This review focuses on the effects of GDNF on the proliferation and differentiation of mammalian SSCs and GDNF-mediated signaling pathways.

Dynamic analysis of Ca2+ level during bovine oocytes maturation and early embryonic development

Mammalian oocyte maturation and early embryo development processes are Ca(2+)-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca2+ and its dynamic changes in the processes of bovine oocytes maturation, in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) embryo development. During the germinal vesicle (GV) and GV breakdown stage, Ca2+ was distributed in the cortical ooplasm and throughout the oocytes from the MI to MII stage. In IVF embryos, Ca2+ was distributed in the cortical ooplasm before the formation of the pronucleus. In 4-8 cell embryos and morulas, Ca2+ was present throughout the blastomere. In PA embryos, Ca2+ was distributed throughout the blastomere at 48 h, similar to in the 4-cell and 8-cell phase and the morula. At 6 h after activation, there was almost no distribution of Ca2+ in the SCNT embryos. However, Ca2+ was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos. In this study, Ca2+ showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not. Systematic investigation of the Ca2+ location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.

Establishment of experimental subarachnoid hemorrhage model with endo-cerebrovascular perforation / 中华急诊医学杂志

Objective To establish an experimental subarachnoid hemorrhage(SAH)model with endo- cerebrovascular peroration.Method The right external carotid artery of SD rats were isolated,leaving a stump of approximately 3 to 4 mm.A-3-O monofilament nylon suture was inserted up through the stump of external carotid artery to the internal carotid artery for about 18～19 mm.A small resistance was usually felt,and the suture was then advanced 2 mm further and the suture was immediately withdrawn.Two hours or two days after SAH induction,SAH extension was observed.Two days after SAH induction,the diameter of the basilar artery was measured.Results SAH extends from the ipsilateral artery to the eontralateral artery after SAH induction.The diameters of basilar arteries in SAH animals were smaller than those of control rats,indicating the present of cerebrovascular spasm in SAH animals.Conclusions The endo-cerebrovascular perforation technique for establishing a non-craniotomy SAH model is reliable.