关键词: 牦牛, 乳腺上皮细胞, HSP70, 冷应激

Abstract: The present study was carried out to investigate the effect of cold stress on the expression of Heat shock protein 70 (HSP70)in mammary epithelial cells of the yak. The changes of HSP70 mRNA expression in the condition of cold stimulation of 10℃ were determined by use of realtime fluorescent quantitative PCR technology.The results showed that no significant changes (P >0. 05)of HSP70 mRNA expression would be found if the mammary epithelial cells were treated only in the condition of 10℃ for 2 h,4 h,6 h and 8 h,respectively. A significant increase of HSP70 mRNA expression would be found and reached a peak value (P <0.01)at the 6th hour of cold treatment if the mammary epithelial cells were first treated in the condition of 10℃ for 2 h,4 h,6 h and 8 h,respectively,and then reheated for 4h. A significant increase of HSP70 mRNA expression would also be found and reach a peak value (P <0. 01)at the 4th hour of rewarming if the mammary epithelial cells were first treated for 4 h in the condition of 10℃,and then reheated for 2 h,4 h,6 h and 8 h,respectively. It is concluded from this study that an increase of HSP70 mRNA expression does not occur in the process of cold treatment,but in the process of rewarming; meanwhile the increase of HSP70 mRNA expression is to some extentrelated with the time duration.

Key words: Yak, Mammary epithelial cells, HSP70, Cold stress