热应激对鸡脾脏和法氏囊细胞凋亡的影响及其调节

 18只 AA肉鸡于22℃饲养。30日龄时，随机分成3组，分别进行0 、5和10h的41℃高温应激处理。用流式细胞仪检测应激后不同时间脾脏和法氏囊细胞 DNA含量、细胞凋亡率以及Caspase-3和Bcl-2的表达。结果表明，应激处理0、5和10 h时，脾脏DNA合成期（S期）细胞比例分别是4.67%、5.11%、4.78%，法氏囊S期细胞分别是30.52%、24.71%、24.04%；脾脏和法氏囊细胞凋亡率分别是0.22%、0.42%、0.32%和0.32%、0.62%、0.41%；脾脏和法氏囊 caspase-3表达阳性细胞率分别为5.49%、10.36%、9.80%和8.60%、10.51%、9.41%； Bcl-2表达阳性细胞率脾脏分别是31.32%、24.01%和29.26%，法氏囊则是30.24%、27.10%、31.54%；脾脏细胞凋亡率，应激后5 h 与 0 和10 h有显著差异（P＜0.05）；在高温应激过程中，脾脏和法氏囊的细胞凋亡率与Caspase-3表达阳性细胞率呈方向一致的变化关系，均是从0 h到5 h逐渐升高，以后又逐渐下降；而与Bcl-2表达阳性细胞率呈反向变化关系。据此说明高温应激能明显影响脾脏和法氏囊细胞凋亡，而这种细胞凋亡的变化受Caspase-3和Bcl-2表达的调节。

Effect of Heat Stress on Apoptosis in Chicken Spleen and Bursa Cells and Their Regulation

Eighteen AA chicken were raised at 22 , and at 30-day-old of age they were stressed for 0 , 5 and 10 h at 41 . The DNA contents of spleen and bursa, the ratio of apoptosis and the expression of caspase-3 and Bcl-2 in the spleen and bursa were measured by flow cytometry. The results were as follows: Cell ratio of S phase (DNA synthetic phase ) in the spleen was 4.67%,5.11% and 4.78% , that of the bursa was 30.52%,24.71% and 24.04% at 0,5 and 10 h after heat stress respectively. Apoptotic rate of spleen was 0.22%, 0.42% , 0.32% and that of the bursa was 0.32%,0.62% and 0.41%, respectively. The positive ratios of the cells expressing caspase-3 in the spleen was 5.49%, 10.36% and 9.80%; and that in the bursa was 8.60%, 10.51% and 9.41% respectively. The positive ratio of the cells expressing Bcl-2 protein in the spleens was 31.25%, 24.01% and 29.26%, and that of the bursa was 30.24%, 27.10% and 31.54%, respectively. The apoptotic rate of spleens of heat stressed chickens for 5 h was significantly different from those for 0 and 10 h, separately (P<0.05. After heat stress, apoptotic rate and positive expression of caspase-3 in spleen and bursa increased gradually from 0 to 5 h, and then decreased slowly . The changes of apoptotic rate were parallel positively with the changes of caspase-3 expression, but negatively with the changes of Bcl-2 expression in the spleens and bursa during heat stress. It is concluded that the apoptosis of spleen and bursa cells was obviously affected by heat stress and regulated by the expression of caspase-3 and Bcl-2 protein.