Kisspeptin-10对热应激引起大鼠心肌损伤的影响

Effects of kisspeptin-10 on myocardial injury induced by heat stress in rats

试验旨在探究kisspeptin-10对热应激造成的大鼠心肌损伤的影响及其分子机制。将24只SD雄性大鼠随机分为3组(对照组、热应激组和热应激后kisspeptin-10皮下注射组),每组8只。诱导发生热应激后采用透射电镜、HE染色和masson染色来观察心脏组织病理变化情况;并采用RT-PCR技术检测与心肌损伤通路相关基因ITGA4、ITGB8、BNP、MYL7、HIF-1α和ITGB7的mRNA在心肌中的变化;用Western-Blot验证其关键蛋白ITGB8和BNP表达的变化。与对照组相比,热应激组(H)出现心肌损伤现象;热应激后kisspeptin-10皮下注射组(KH)与热应激组(H)相比,心肌纤维排列较整齐,细胞核染色较均匀,纤维增生减少,线粒体空泡和线粒体嵴断裂现象明显减少;另外,心脏组织中ITGB8和BNP在热应激组(H)发生上调,而热应激后kisspeptin-10皮下注射组(KH)与热应激组(H)相比显著下调。本研究从形态学和分子机制方面探究kisspeptin-10缓解SD大鼠由热应激所致心肌损伤的途径。一方面ITGB8作为心肌细胞膜的异二聚体在热应激后表达发生变化,另一方面热应激后心肌组织形态学上的改变。这些由热应激引起紊乱的在kisspeptin-10干预后有趋于正常表现,为进一步研究kisspeptin-10在热应激导致心肌损伤中的缓解作用机制提供了理论基础。

The aim of our present study was to investigate the effects of kisspeptin-10 on the heat stress induced myocardial injury in SD rats. Twenty-four male Sprague-Dawley rats were randomly assigned into three groups： control group（ C）,heat stress group（ H） and hypodermic injection of kisspeptin-10 after heat stress（ KH）. After being exposed to different treatments,histomorphology of heart tissues in three groups were observed through hematoxylin eosin（ HE） staining,masson staining and transmission electron microscope（ TEM）. Then,the mRNA expression of cardiomyopathy genes including ITGA4,ITGB8,BNP,MYL7,HIF-1α and ITGB7 were tested by RT-PCR. The key protein ITGA4,ITGB8 and BNP were involved in many heart diseases pathways and were detected by Western-blot. The results showed that there was a degree of myocardial damage in heat stress group compared to control. However,heat stress group with kisspeptin-10 treatment demonstrated a relief symptoms compared to heat stress group（ more regularly arranged cardiomyocytes,more evenly stained nucleus,obviously decreased proliferation of fiber and injured mitochondria）. Furthermore,the genes including ITGB8 and BNP in group H were alterated at the transcription and translation level but tend to be normal in group KH. The effects of kisspeptin-10 on myocardial injury induced by heat stress in rats would provide the theoretical basis to the deeper research.