热应激造成奶牛乳腺上皮细胞损伤并影响乳合成相关载体的基因表达

Heat Stress-induced Cell Injury and Effects on the Gene Expression of Milk Synthesis-related Transporters in Dairy Cow

本试验以奶牛乳腺上皮细胞为模型,旨在寻找热应激下调奶牛泌乳功能的相关因素。42℃高温处理奶牛乳腺上皮细胞0、0.5、1、1.5、2、4、8及12h,检测其对细胞活率,线粒体膜电位,热休克分子及蛋白基因、氧化应激相关基因以及氨基酸和葡萄糖转运载体基因表达的影响。结果显示,不同时间热处理显著降低乳腺上皮细胞活率（P〈0.05）,损伤细胞线粒体膜电位。HSP27基因表达显著下降（P〈0.05）,HSP70基因表达显著上调（P〈0.05）,HSP90基因表达在前4h显著上调（P〈0.05）,后恢复至正常水平,HSF-1基因表达在某些时间点显著上调（P〈0.05）。氧化应激相关基因Keach样环氧氯丙烷相关蛋白-1（Keap1）表达无显著变化（P〉0.05）,核因子E2相关因子2（Nrf2）表达显著上调（P〈0.05）,NAD（P）H脱氢酶醌-1（NQO1）表达显著上调（P〈0.05）。跨膜氨基酸转运载体SLC7A7基因表达在1h和4h显著上调（P〈0.05）。葡萄糖转运载体GLUT1及GLUT8基因表达显著下调（P〈0.05）。葡萄糖转运载体GLUT12在热处理0~2h表达显著上调,4~12h显著下调（P〈0.05）。热应激能够显著降低奶牛乳腺上皮细胞活率,引起氧化应激,改变热休克蛋白和分子及跨膜转运载体的基因表达。

Bovine mammary epithelial cell was chosen as the model to find the factors impairing lactation performance of dairy cow during heat stress.Cell vitality,mitochondrial membrane potential and the expression of genes related to heat shock molecule and proteins,oxidative stress,amino acids and glucose transporters were detected in the bovine mammary epithelial cells treated for 0,0.5,1,1.5,2,4,8and 12 hat 42 ℃,respectively.The result showed that different heat treatment time significantly reduced mammary epithelial cell vitality（P〈0.05）and damaged mitochondrial membrane potential.The expression of HSP27 decreased significantly（P〈0.05）,while HSP70 increased significantly（P〈0.05）.The expression of HSP90 increased significantly in 0-4h（〈P0.05）,and returned to normal level after then.The expression of HSF-1increased significantly in some time points（P〈0.05）.The gene expression of Keach like ECH-associated protein-1（Keap1）showed no significant difference（P〉0.05）,while nuclear factor-E2-related factor 2（Nrf2）and NAD（P）H dehydrogenase quinone-1（NQO1）increased significantly（P〈0.05）.The gene expression of transmembrane amino acid transporter SLC7A7 increased significantly in 1hand 4h（P〈0.05）.The gene expression of glucose transporters GLUT1 and GLUT8decreased significantly（P〈0.05）.The expression of glucose transporter GLUT12 increased significantly during 0-2h,and decreased significantly during 4-12h（P〈0.05）.In conclusion,heat stress could significantly reduce the cell vitality,cause oxidative stress,change the gene expression of heat shock proteins and molecule and membrane transport carriers.