卵龄和脉冲持续时间对小鼠卵母细胞电活化效果的影响

EFFECTS OF EGG AGE AND PULSE DURATION ON ELECTRICAL ACTIVATION OF MOUSE OOCYTES

实验研究了相同电场强度，一次脉冲条件下，不同脉冲持续时间和不同卵龄对小鼠卵母细胞电活化效果的影响。结果说明：（１）在场强０．４５ＫＶ／ｃｍ，一次脉冲持续时间为１０、２０和４０ｓ时，卵母细胞活化率很低，仅为９．８％、５． ５％和１２％；当脉冲持续８０、１６０、３２０、６４０和１２８０ｓ时，活化率明显升高，分别为３６．５％、５３．３％、５９．７％，５１．２％和３９．４％；脉冲持续时间对卵母细胞碎裂率影响不明显，但死亡率随脉冲持续时间延长有增加趋势。（２）在脉冲持续时间为１６０—６４０范围内，注射ｈＣＧ后１９和１７小时卵母细胞活化率（平均分别为６７．７％和５６．４％）明显高于注射ｈＣＧ后１３和１５小时卵母细胞活化率（平均３２．８％和４０.５％）。

In this study the effects of different pulse durations and age of the egg on electrical activation of mouse oocytes were examined. Kun-ming mice of 8-12 weeks old were superovulated with PMSG and hCG. Oocytes were recovered from mice killed at different hours post hCG and were denuded of cumulus with hyaluronidase. The denuded oocytes were stimulated in 0. 3mol/L mannitol with single electrical pulses of the same strength but different durations. After cultured in Whitten medium for 5-6 hours, the treated oocytes were observed for activation and the criteria for judgement of activation were the same as those reported by Collas et al. (Theriogenology 32: 835, 1989). The major results are as follows: (1) With single pulses of 0. 45kV/cm, short durations of 10, 20 and 40 s produced low activation rates of 9. 8 %, 5. 5 % and 12 %, respectively. However, when the pulse durations were prolonged to 80, 160, 320, 640 and 1280s, the rates of activation increased markedly, reaching 36. 5 %, 53. 3%, 59. 7 %, 51. 2 %and 39. 4 %, respectively. The pulse duration had no effect on fragmentation of the oocyte, but its prolongation tended to increase oocyte lysis. (2) With pulse durations of 160-640s, the activation rates of the oocytes collected 19 (67. 7 % ) and 17 (56. 4% ) hours post hCG were markedly higher than those in the oocytes recovered 13 (3. 28%) and 15 (40. 5%) hours post hCG.