Abstract
The aim of this study was to determine the effect of steroids and human chorionic gonadotropin (HCG) on in vitro maturation and ovulation of oocyte in Pseudobagrus fulvidraco. Oocytes were incubated in the media Leibovitz L15 supplemented with the various concentration of $17\alpha,\;20\beta-dihydroxy-4-pregnen-3-one(17\alpha20{\beta}OHP),\;17\alpha-hydroxyprogesterone(17{\alpha}OHP),\;progesterone(P_4),\;estradiol-17\beta(E_2)and\;HCG$. After 60 hours incubation, the maturation ability of oocyte was assessed by the appearance of germinal vesicle breakdown (GVBD). GVBD was significantly enhanced by the addition of $17\alpha20{\beta}OHP,\;17{\alpha}OHP,\;P_4\;and\;HCD(P<0.05)$. The highest CVBD was observed when $17\alpha20{\beta}OHP$ and HCG were supplemented to media. When oocytes were cultured for 16 hours in media containing $10\~1,000\;ng/ml\;17\alpha20{\beta}OHP,\;17{\alpha}OHP\;and\;P_4$, the rate of GVBD in oocytes cultured in the medium supplemented with 100 ng/ml $17\alpha20{\beta}OHP(65\%)$ was significantly higher than that with $17{\alpha}OHP\;(40\%)\;and\;P_4(35\%)$. The efforts of $17\alpha20{\beta}OHP$ and HCG on GVBD were assessed by various concentration of these hormones. When oocytes were cultured for 60 hours in various media containing $1\~1,000\;ng/ml\;17{\alpha}20{\beta}OHP\;or\;5\~1,000\;IU/ml$ HCG, the GVBD of oocytes was significantly increased in the medium with $10\~100\;ng/ml\;17\alpha20{\beta}OHP$ and 500 IU/ml HCT. When oocytes were cultured in the various media supplemented with $1\~1,000\;ng/ml\;17\alpha20{\beta}OHP\;or\;5\~1,000\;IU/ml$ HCG for 60 hours, the media with $1\~100\;ng/ml\;17\alpha20{\beta}OHP\;or\;50\~1,000IU/ml$ HCG significantly increased in the rate of ovulation. However supplementation with $1,000\;ng/ml\;17\alpha20{\beta}OHP$or 5 IU/ml HCG did not improve the rate of ovulation compared to controls. This results indicate that supplementation of steroid and HCG except $E_2$ can improve the in vitro maturation and ovulation of oocyte in P. fulvidrac; HCG and $17\alpha20{\beta}OHP$ may be more effective than other steroids on oocyte maturation and ovulation in P. fulvidraco.
동자개 난모세포의 성숙과 배란에 있어 스테로이드와 HCG(human chorionic gonadotropin)의 효과에 대한 실험이 in vitro에서 이루어졌으며, 난모세포들은 $17\alpha,\;20\alpha-dihydroxy4-pregnen-3-one\;(17\alpha\;20\alpha\;OHP),\;17\alpha-hydroxyprogesterone\;(17\alpha\;OHP),\;progesterone\;(P_4),\;estradiol-17{\alpha}E_2)$ 과 HCG가 첨가된 Leibovitz L15 배지에서 성숙되어졌다. 60시간 배양후에 난모세포의 성숙능력은 난핵포붕괴(germinal vesicle breakdown, GVBD) 비율에 의해 평가되었다. GVBD 비율은 $17\alpha\;20\alpha\;OHP,\;17\alpha\;OHP,\;P_4$ 그리고 HCG의 첨가에 의해 유의하게 (P<0.05) 증가하였으며, 그 중 $17\alpha\;20\alpha\;OHP$ HCG에서 가장 높은 GVBD 비율을 보였다. 난모세포들 $17\alpha\;20\alpha\;OHP,\;17\alpha\;OHP,\;P_4$가 $10\~1,000ng/ml$포함된 배지에서 16시간 배양한 결과, $17\alpha\;20\alpha\;OHP\;10\~100ng/m1(65\%)$의 GVBD 비율은 $17\alpha\;20\alpha\;OHP(40\%)$와 $P_4(35\%)$에서 보다 나은 효과를 보였다. GVBD유도에 대한 효과는 $17\alpha\;20\alpha\;OHP$에서 $10\~100\;ng/ml$배지, HCG를 첨가하여 60시간 배양한 배란유도 실험에서 $17\alpha\;20\alpha\;OHP\;10\~100ng/ml$에서, HCG는 $50\~500IU/ml$의 배지에서 배란율이 유의하게 증가하였다. 그러나 $17\alpha\;20\alpha\;OHP\;1,000ng/m1$와 HCG 5IU/ml의 배지에서는 대조구의 배란율과 차이를 보이지 않았다. 이러한 결과로 $E_2$를 제외한 스테로이드와 HCG는 동자개의 난모세포 성숙과 배란을 in vitro에서 유도할 수 있으며, $17\alpha\;20\alpha\;OHP$와 HCG는 다른 스테로이드에 비해 높은 율의 난모세포 성숙과 배란을 유도하였다.
(Department of Biology, Dongeui University)
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