Abstract:

【Objective】 This experiment was made to investigate the effect of gonadotrophin on follicle development and oocyte maturation and development in grafted ovaries in male recipient mice. 【Method】 Ovaries from 1-day-old mice were xenografted underneath the kidney capsule of 7-12-week old male recipient mice. Graft recipients were treated with or without xogenous gonadotrophin prior to graft collection. The 7-12-week old female mice were treated with gonadotrophin and used as controls. Twenty-one days after grafted, the ovarian grafts were recovered for examination of their size, recoverable proportion and follicular growth. The oocyte maturation and fertilization were conducted in in vitro. The 2-cell cleavage rate and Blastocyst rate were determined. 【Result】 The ovary recovery rate was 85.4% in recipients without treatment, insignificantly differed from the treated group (90.7%) (P＞0.05). The follicles of grafts could develop to maturation stage and GV oocytes of (41.4±25.8) per ovarian graft were retrieved. The in vitro matured GV oocytes could develop to two-cell embryos in the rate of 17.5%, but not to blastocyst in the non-treated group. The follicles could develop to the antral stage and undergo periovulatory changes following xenografting and exposure to a luteinizing stimulus, with expanded cumulus-oocyte complex, mucified cumulus cell and corpus luteum. MII oocytes as well as GV oocytes were retrieved from the treated group, the yield of MII and GV oocytes per ovarian graft was (8.5±7.1) and (33.4±20.1), the two-cell cleavage rate was 44.3% and 33.9%, and the blastocyst rate was 6.3% and 0.48%, respectively. There was a significant difference in the two-cell cleavage rate and blastocyst rate between groups treated with or without xogenous gonadotrophin (P＜0.01), but not in the yield of oocytes (P＞0.05). The two-cell cleavage rate of oocytes collected from 21 d grafts was lower than that of the control group (P＜0.01), and without significant difference in the blastocyst rate between MII oocytes from the grafts and the control (P＞0.05). 【Conclusion】Stimulation with exogenous gonadotrophins did not significantly increase oocyte yield of grafted ovaries in male recipients but did enhance the competence of follicular growth, oocyte maturation and embryo development.

Key words: ovary, xenograft, follicle, oocyte, male, mice