RESUMO
With increasing age in women, the ovarian function declines, which leads to decreased follicle generation, declined female fertility and age-related diseases ultimately. Female germline stem cells are epithelial cells existing on the ovarian surface, which can divide into new stem cells symmetrically and differentiate into germ cells and granulosa cells asymmetrically. The discovery of female germline stem cells brings much hope for the post-natal renewal of oocytes and solving female infertility problems. Ovarian germline stem cell niche in which female germline stem cells live is the surrounding microenvironment which plays an essential role in maintaining the function of female germline stem cells. Many factors including nutrition supply, protein, cytokines and signaling pathways can control the biological characters of female germline stem cells, and also influence their proliferation and differentiation. This paper reviewed the knowledge about the influencing factors and regulatory mechanisms of the function of ovarian germline stem cell niche.
RESUMO
Preparation of a poly (gamma-glutamic acid)-cisplatin conjugate was introduced and its in vitro antitumor effect was investigated. Poly (gamma-glutamic acids) was obtained by using fermentation methods. The hydrolyzed small molecular weight of poly (gamma-glutamic acids) was prepared by acid hydrolysis. The interaction between poly (gamma-glutamic acids) -cisplatin conjugate (PGA-CDDP) and DNA was investigated by PCR model. MTT assay was used to investigate the in vitro anticancer activity of the conjugate. Apoptosis assay of the conjugate was investigated by FCM assay and the in vivo toxicity was also proceeded. The results showed that the poly (gamma-glutamic acids) -cisplatin conjugate was obtained successfully and its yield is 10% - 12%. It has obvious antitumor effects on human liver tumor BEL7404 cells, human lung tumor H446 cells and human colon tumor RKO cells. At the same time, it also has apoptosis effects on the three kinds of tumor cell lines. The in vivo toxicity of PGA-CDDP was examined in normal mice and the results showed that the in vivo toxicity of this conjugate was significantly lower than that of free CDDP. In conclusion, the poly (gamma-glutamic acids) -cisplatin conjuate could be used as a potential clinic antitumor drug. The poly (gamma-glutamic acids) obtained by fermentation can be used as a valuable drug carrier system.