Experiment 1 . the present investigation was undertaken to ascertain the effects of no at high level on porcine oocyte meiotic development . cumulus - enclosed oocytes ( ceos ) and denuded oocytes ( dos ) were obtained from the follicles ( 2 - 6 mm diameter ) 实验一研究了no对猪卵母细胞成熟的影响，包括卵丘细胞包被的卵母细胞( cumulus - enclosedoocytes , ceos )和脱除卵丘的卵母细胞( denudedoocytes , dos ) 。
As the most common used small experimental animals , rat and mouse have inconsistencys in reproduction , especially in gondonatorpin inducing oocyte maturation . our research was undertook to elucidate which kind of gonadotropins play role in oocyte meiotic maturation , the effects of fsh ans lh / hcg on mouse and rat oocyte maturation in vitro were examined under different culture models 在体外自发成熟模型中，大鼠的去卵丘裸卵( do )自发成熟发生要较卵丘包被的卵母细胞( ceo )早， do培养2h时gvbd可达到88 ，而ceo培养2h的gvbd为53 。
Rat cumulus - enclosed oocyte ( ceo ) and denuded oocyte ( do ) both spontaneously resume meiotic maturation in vitro , when cultured for 2h , the germinal vesical breakdown percentage of do reaches up to 88 % , and ceos get 53 % . oocytes begin to extrude first polar body 1 ( fb1 ) when cultured for 8h . mouse oocyte spontaneous maturation in vitro can be inhibited by 4mm hypoxanthine ( hx ) or 25um 3 - isobutyl - methylxanthine ( ibmx ) . while , 4mm hx can not inhibit the spontaneous maturation of rat oocyte , and the lowest effective concentration of ibmx to inhibit rat oocyle spontaneous maturation in vitro is 50um . treated with the same concentration of ibmx , gvbd percentage of rat ceo is lower than that of do , the results indicat that cumulus cells delay rat oocyte spontaneous maturation and potentate the inhibition effect of ibmx , but it ' s not the case on mouse Ceo和do培养8h时都开始排出pb1 ；在卵母细胞成熟抑制模型中， 4mm次黄嘌呤( hx )和25 m的异丁基甲基黄嘌呤( ibmx )是小鼠卵母细胞成熟的有效抑制剂，但4mm的hx抑制大鼠卵母细胞成熟效果不理想，用hx - m199和hx - mem培养24h ， gvbd率分别为61 ， 81 ，而ibmx有效抑制大鼠卵母细胞自发成熟的最小浓度为50 m ， ibmx可以降低大鼠ceo和do的gvbd率，但ceo中的卵母细胞gvbd率要显著低于do的gvbd率， 100 m的jbmx处理24h后，大鼠ceo和do的gvbd率分别为24 ， 84 ，提示卵丘细胞的存在可以延迟大鼠卵母细胞的自发成熟，有助于抑制卵母细胞成熟，但在小鼠上ceo和do的自发成熟差异不明显。
We get to the conclusions : ( 1 ) the histon acetylation level has some derease in the lung of cloned cattle ; ( 2 ) in the cloned cattle xiaobai , the histone acetylation level is lower than that in normal control , however , higher or adjacent to that in other dead cloned cattle ; ( 3 ) there is no significant difference during those cattle from the cumulus , fetal fibroblast and adult fibroblast cell donor 我们发现： ( 1 )在克隆牛中组蛋白乙酰化水平基本上都有所降低； ( 2 )克隆牛xiaobai乙酰化水平比正常牛低，而基本上是高于或接近死亡克隆牛水平的； ( 3 )在我们所研究的三个供体细胞系(卵丘细胞，成体成纤维细胞和胎儿成纤维细胞)中，乙酰化水平无明显差异。
