THE EFFECT OF HYPOXANTHINE ON MOUSE OOCYTE GROWTH AND DEVELOPMENT INVITRO - MAINTENANCE OF MEIOTIC ARREST AND GONADOTROPIN-INDUCED OOCYTE MATURATION
THE EFFECT OF HYPOXANTHINE ON MOUSE OOCYTE GROWTH AND DEVELOPMENT INVITRO - MAINTENANCE OF MEIOTIC ARREST AND GONADOTROPIN-INDUCED OOCYTE MATURATION
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DOI：
10.1016/0012-1606(87)90037-6
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发表时间：
1987-02-01
影响因子：
2.7
通讯作者：
DOWNS, SM
中科院分区：
文献类型：
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作者：
EPPIG, JJ;DOWNS, SM
据估计，小鼠卵泡液中次黄嘌呤的浓度为2-4毫米，尽管该浓度在体外维持完全成熟的小鼠卵母细胞的减数分裂停滞，但卵泡液中次黄嘌呤浓度的降低并不会诱导卵母细胞成熟（J. J. Eppig， P. F. Ward-Bailey, and D. L. Coleman, Biol）。复写33,1041-1049,1985)。在本研究中，我们评估了2 mM次黄嘌呤对体外卵母细胞生长发育的影响，并确定了促性腺激素在次黄嘌呤持续存在的情况下刺激卵母细胞成熟的能力。从10- 11日龄小鼠中分离卵母细胞-颗粒细胞复合物，并在存在或不存在2 mM次黄嘌呤的情况下进行培养。10 ~ 11日龄小鼠的卵母细胞处于生长中期，没有进一步发育，不能进行减数分裂成熟。在12天的培养期间，颗粒细胞封闭的卵母细胞的大小大约增加了一倍，无论是否存在次黄嘌呤，50-70%的卵母细胞都有能力经历生发囊泡破裂（GVBD）。次黄嘌呤在12天的培养期间促进卵母细胞与其同伴颗粒细胞的持续结合，因此对卵母细胞的发育有有益的影响。大多数在缺乏次黄嘌呤的情况下获得GVBD能力的卵母细胞发生自发性GVBD。相比之下，95%的gvbd能力卵母细胞在次黄嘌呤的作用下仍处于减数分裂停滞状态。在12天后停用次黄嘌呤后，75%的GVBD能力卵母细胞发生了GVBD。这些结果表明，次黄嘌呤和/或其代谢物在体外生长并获得GVBD能力的卵母细胞中维持减数分裂停滞。促卵泡激素（FSH），而不是黄体生成素或人绒毛膜促性腺激素，在持续存在次黄嘌呤的情况下诱导卵母细胞GVBD。在次黄嘌呤持续存在的情况下，卵泡刺激素刺激卵母细胞成熟的频率显著高于脱粒卵母细胞与脱粒卵母细胞共培养（P < 0.01）。FSH不能诱导脱去的卵母细胞与颗粒细胞共培养成熟。从22日龄小鼠中分离卵丘细胞复合物，通过注射外源性促性腺激素促进卵巢卵泡发育，也获得了类似的结果。基于这些结果，我们假设GVBD在这些培养系统中是由fsh诱导的颗粒/积云细胞的阳性信号促进的，而不仅仅是由于剥夺了次黄嘌呤的减数分裂抑制作用。
The concentration of hypoxanthine in mouse follicular fluid has been estimated to be 2-4 mM, and although this concentration maintains meiotic arrest in fully grown mouse oocytes in vitro, oocyte maturation in vivo is not induced by a decrease in the concentration of this purine in follicular fluid (J. J. Eppig, P. F. Ward-Bailey, and D. L. Coleman, Biol. Reprod. 33, 1041-1049, 1985). In the present study, the effect of 2 mM hypoxanthine on oocyte growth and development in vitro was assessed and the ability of gonadotropins to stimulate oocyte maturation in the continued presence of hypoxanthine was determined. Oocyte-granulosa cell complexes were isolated from 10- to 11-day-old mice and cultured in the presence or absence of 2 mM hypoxanthine. Oocytes from 10- to 11-day-old mice are in mid-growth phase and, without further development, are incompetent of undergoing meiotic maturation. During a 12-day culture period the granulosa cell-enclosed oocytes approximately doubled in size and, regardless of the presence or absence of hypoxanthine, 50-70% developed competence to undergo germinal vesicle breakdown (GVBD). Hypoxanthine promoted the continued association of oocytes with their companion granulosa cells during the 12-day culture period, and therefore had a beneficial effect on oocyte development. Most of the oocytes that acquired GVBD competence in the absence of hypoxanthine underwent spontaneous GVBD. In contrast, 95% of the GVBD-competent oocytes were maintained in meiotic arrest by hypoxanthine. Following withdrawal of the hypoxanthine after the 12-day culture, 75% of the GVBD-competent oocytes underwent GVBD. These results show that hypoxanthine, and/or its metabolites, maintains meiotic arrest in oocytes that grow and acquire GVBD competence in vitro. Follicle-stimulating hormone (FSH), but not luteinizing hormone or human chorionic gonadotropin, induced oocyte GVBD in the continued presence of hypoxanthine. FSH stimulated oocyte maturation at a significantly (P < 0.01) higher frequency than coculture of the granulosa cell-denuded oocytes with granulosa cells in the continued presence of hypoxanthine. FSH did not induce the maturation of denuded oocytes cocultured with granulosa cells. Similar results were obtained using oocyte-cumulus cell complexes isoalted from 22-day-old mice wherein ovarian follicular development was promoted by injection of exogenous gonadotropin. Based on these results, it is hypothesized that GVBD was promoted in these culture systems by an FSH-induced positive signal from granulosa/cumulus cells, and not simply by deprivation from the meiosis-arresting action of hypoxanthine.