热应激对鸡胸腺细胞凋亡的影响及其调节机理

The effect and regulation of heat stress to apoptosis on chicken thymocytes

18只AA肉鸡于 2 2℃饲养。 30日龄时 ,随机分成 3组 ,分别进行 0 ,5和 10h的 4 1℃高温应激处理。用流式细胞仪检测胸腺细胞DNA含量、细胞凋亡率以及细胞caspase 3和Bcl 2的表达。结果 :应激处理 0 ,5和 10h时 ,(1)DNA合成期 (S期 )细胞比例分别是 2 77% ,3 2 8%和 2 31% ;(2 )胸腺细胞凋亡率分别是 3 99% ,11 15 %和3 31% ;(3)caspase 3表达阳性细胞率分别为 14 2 4 % ,2 7 0 1%和 10 84 % ,Bcl 2表达阳性细胞率分别是 2 0 5 9% ,15 13%和 2 7 92 % ;(4 )应激 5h与 0和 10h的细胞凋亡率、caspase 3和Bcl 2的阳性细胞表达率均有显著差异 (P <0 0 5 ) ;(5 )应激处理鸡的胸腺细胞凋亡率、caspase 3表达阳性细胞率从 0h到 5h逐渐升高 ,以后又逐渐下降。在高温应激过程中 ,胸腺细胞凋亡率与caspase 3表达阳性细胞率呈平行的变化关系 ,而与Bcl 2表达阳性细胞率呈反向变化关系。这些结果均说明 :高温应激能明显影响胸腺细胞凋亡 ,而这种细胞凋亡的变化受caspase 3和Bcl 2表达的调节。

Eighteen AA chickens were raised at 22 ℃,and at 30 days old they were stressed for 0,5 and 10 h at 41 ℃.The DNA contents of thymocytes,the ratio of apoptosis the expression of caspase 3 and Bcl 2 in thymocytes were measured by flow cytometry The results were as follows:(1) Cell ratios of S phase (DNA synthetic phase )were 2 77%,3 28% and 2 31% at 0,5 and 10 h after heat stress respectively (2) Apoptotic rates of thymocytes were 3 99%,11 15% and 3 31% respectively (3) The positive ratios of the cells expressing caspase 3 were 14 24%,27 01% and 10 84%; and that of the cells expressing Bcl 2 protein were 20 59%,15 13% and 27 92% (4)The apoptotic rates of thymocytes,the expression of caspase 3 and Bcl 2 in thymocytes of heat stressed chickens at 5 h were significantly different from those at 0 and 10 h separately( P <0 05).(5)After heat stress,apoptotic rates and positive expression of caspase 3 in thymocytes in creased gradually from 0 to 5 h and them decreased slowly.The changes of apoptotic rates were paralleled positively with the changes of caspase 3 expression,but negatively with the changes of Bcl 2 expression during heat stressing It is suggested that the apoptosis of thymocytes were obviously effected by heat stress and regulated by the expression of caspase 3 and Bcl 2