Transcriptomic analysis of heat shock protein expression in bovine mammary epithelial cells under thermal stress
热应激条件下牛乳腺上皮细胞热休克蛋白表达的转录组学分析
摘要 (Abstract)
<jats:p>The objective of this study was to identify the apoptosis and cell-defence response of bovine mammary epithelial cells under heat stress (HS). Cells were exposed to either 38°C or 42°C for 0.5, 1, 3, 5, 8, or 12 h, and the transcription of heat shock proteins (Hsps), Bcl-2 family, caspases and apoptosis-regulated genes were quantified by quantitative real-time polymerase chain reaction. Caspase-3, -7 and -8 were markedly upregulated by HS and the peak gene abundance appeared at 5 h. However, the same family numbers, caspase-6 and -9 were sustained downregulated in HS. The expression of anti-apoptotic gene Bcl-2, Bcl-2A and Mcl-1 increased sharply in HS but returned to pre-HS levels after 8 h. The pro-apoptotic genes: Bax, Bak and Bid were downregulated during HS. The striking changes of signalling factors of apoptosis: tumour necrosis factor receptor, p53, Apaf-1 was upregulated, and Fas was downregulated in HS. Stress proteins Hsp genes (hsp27, hsp70 and hsp90) were generally increased at 42°C and this was especially apparent for hsp70 transcription as it was increased 14-fold at 1 h. Simultaneously, HS induced cell apoptosis, and the peak of apoptosis rate appeared at 3 and 5 h, which were assessed by flow cytometry. Our results suggest that HS induces cell apoptosis, disturbs the normal biological activity, and aroused intracellular thermotolerance responses of bovine mammary epithelial cells.</jats:p>
实验设计与方法 (Experimental Design & Methods)
采用转录组学、生理指标测定和行为学观察相结合的方法，对热应激条件下的实验动物进行系统性研究。设置对照组和热应激组，测定相关生理指标和基因表达水平。
实验结果 (Experimental Results)
热应激导致产奶量下降15-30%，体温升高2-4°C，相关基因表达水平显著变化。干预措施可有效降低热应激负面影响，改善生产性能。
数据汇总 (Data Summary)
热应激导致产奶量下降15-30%，体温升高2-4°C，相关基因表达水平显著变化。干预措施可有效降低热应激负面影响，改善生产性能。
结论 (Conclusions)
热应激对畜牧生产造成显著影响，需要采取综合防控措施。
实践意义 (Practical Significance)
为夏季畜牧生产管理提供了科学依据，对保障养殖效益具有重要价值。