右美托咪定对肠源性脓毒症大鼠肠屏障功能保护及抗凋亡作用的机制研究

Mechanism of dexmedetomidine on intestinal barrier function protection and itsanti-apoptot⁃ic effect in gut-derived sepsis rats

目的:探究右美托咪定(DEX)对肠源性脓毒症大鼠肠屏障功能保护及抗凋亡的作用机制。方法:按随机数字表法将60只大鼠分为空白对照组(Control)、模型组(Model)、低剂量DEX组(5μg/kg)和高剂量DEX组(10μg/kg),每组15只;将模型组、低剂量DEX组和高剂量DEX组大鼠制成脓毒症模型,药物干预后,使用苏木精―伊红(HE)染色观察各组大鼠小肠组织病理学改变;分光光度法检测各组大鼠血清二胺氧化酶(DAO)及D-乳酸水平;ELISA法检测肠黏膜肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)的水平;Western blotting检测大鼠肠组织凋亡相关蛋白Caspase-3、Bax、Bcl-2表达情况。结果:HE染色结果显示,使用DEX后大鼠上皮细胞脱落减少,间质出现水肿减少,凋亡细胞也显著减少。与空白对照组比较,模型组DAO活性、D-乳酸、TNF-α、IL-6水平、Bax蛋白表达及Caspase-3蛋白表达显著升高,Bcl-2蛋白表达显著降低(P<0.01);与模型组比较,低剂量DEX组和高剂量DEX组大鼠DAO活性、D-乳酸、TNF-α、IL-6水平、Bax蛋白表达及Caspase-3蛋白表达显著降低(P<0.01),且高剂量DEX组低于低剂量DEX组(P<0.01),Bcl-2蛋白表达显著升高(P<0.01),且高剂量DEX组高于低剂量DEX组(P<0.01)。结论:DEX可以降低肠源性脓毒症大鼠炎症反应并抑制凋亡蛋白表达保护肠屏障功能,且在一定浓度范围内高剂量DEX组效果要优于低剂量DEX组。

Objective:To explore the mechanism of dexmedetomidine(DEX)on intestinal barrier function protection and anti-apoptosis in gut-derived sepsis rats.Methods:60 rats were randomly divided into blank control group,model group,low-dose DEX group(5μg/kg)and high-dose DEX group(10μg/kg),with 15 rats in each group.The rat sepsis models were established in model group,low-dose DEX group and high-dose DEX group.After drug intervention,the pathological changes of small intestine tissues were observed by HE staining.The levels of serum diamine oxidase(DAO)and D-lactate in each groups were detected by spectrophotometry.The levels of intestinal mucosa TNF-αand IL-6 were detected by ELISA.The expression of apoptosis-related protein Caspase-3,Bax and Bcl-2 in rat intestinal tissues were detected by Western blot.Results:The results of HE staining showed that desquamation of epithelial cells,interstitium edema,and apoptosis cells were significantly reduced after DEX treatment(P<0.01).Compared with blank control group,DAO activity,levels of D-lactic acid,TNF-αand IL-6,expression of Bax and Caspase-3 proteins were significantly increased in model group(P<0.01),while expression of Bcl-2 protein was significantly decreased(P<0.01).Compared with model group,DAO activity,levels of D-lactic acid,TNF-αand IL-6,expression of Bax and Caspase-3 proteins were significantly decreased in low-dose and high-dose DEX groups,whereas the expression of Bcl-2 protein was markedly increased(P<0.01).These changes were more significant in high-dose DEX group(P<0.01).Conclusion:DEX can reduce inflammatory response in gut-derived sepsis rats,inhibit expression of apoptosis proteins and protect intestinal barrier function,and the effects are better with a high-dose of DEX in certain concentration range.