右美托咪定通过抑制核因子-κB信号通路传导抵抗大鼠肠道缺血再灌注损伤的研究

Dexmedetomidine resists intestinal ischemia-reperfusion injury in rats through inhibition of nuclear factor-κB signaling pathway transmission

目的探究右美托咪定(DEX)对大鼠肠道缺血再灌注(I/R)损伤的治疗作用及机制。方法使用SD大鼠通过肠系膜上动脉闭合构建肠道缺血再灌注模型。将大鼠分为4组,每组10只,处置如下:模型组,正常造模;假手术组,大鼠仅接受开腹手术;低、高剂量实验组,正常造模,术前1 h分别腹腔注射50和100μg·kg^(-1)DEX,模型组和假手术组术前1 h腹腔注射0.9%NaCl(5 mL·kg^(-1))。按邱氏分类法评估肠道黏膜损伤;用免疫组化检测肠神经胶质细胞(EGCs)损伤标志物人自身免疫性胶质纤维酸性蛋白(GFAP)和S-100β表达水平;检测肠道组织湿/干重量比率;并对肠道组织中炎症因子肿瘤坏死因子-α(TNF-α)和白细胞介素-1β(IL-1β)水平和心脏血中肠道脂肪酸结合蛋白(I-FABP)水平进行酶联免疫吸附试验测定;通过蛋白质印迹法分析检测核因子-κB(NF-κB)通路关键蛋白的表达水平。结果假手术组,模型组,低剂量和高剂量实验组的肠道黏膜损伤评分分别为0.20±0.42,4.40±0.52,3.20±0.63和2.00±0.47;肠道湿/干重量比分别为2.01±0.35,5.89±1.23,4.31±0.77和3.27±0.53;肠道中TNF-α水平分别为(476.57±121.37),(884.97±193.46),(665.16±142.09)和(498.33±135.21)pg·g^(-1);心脏血中I-FABP表达量分别为(1.97±0.45),(4.33±1.87),(2.87±0.74)和(2.06±0.31)ng·mL^(-1);Toll样受体4(TLR4)蛋白表达水平分别为1.00±0.20,3.21±0.71,2.21±0.57和1.03±0.22;p-NF-κB p65/NF-κB p65蛋白表达水平比值分别为0.52±0.11,3.75±0.55,2.52±0.47和0.42±0.17;模型组的上述指标与假手术组比较,低、高剂量组的上述指标与模型组比较,低剂量组的上述指标与高剂量组比较,差异均有统计学意义(均P<0.05)。结论DEX预处理对肠道I/R损伤提供有效的保护,可以归因为通过抑制TLR4/NF-κB信号传导途径介导的抗炎作用。

ObjectiveTo investigate the therapeutic effect and mechanism of dexmedetomidine(DEX)on intestinal ischemiareperfusion(I/R)injury in rats.Methods A model of intestinal ischemia-reperfusion was constructed using SD rats through superior mesenteric artery closure.The rats were divided into 4 groups of 10 rats each,and the disposition was as follows:model group(normal modeling),sham-operation group(rats received open surgery only),low and high dose experimental groups(normal modeling,50 and 100μg·kg^(-1)DEX were injected intraperitoneally 1 h before surgery),and saline(5 m L·kg^(-1))was injected intraperitoneally 1 h before surgery in the model and sham-operation groups,respectively.The intestinal mucosal injury was assessed by Chiu classification;the expression levels of human autoimmune glial fibrillary acidic protein(GFAP)and S-100β,markers of enteric glial cells(EGCs)injury,were measured by immunohistochemistry;and the expression levels of S-100βwere measured.Wet/Dry ratios of intestinal tissues were measured,and levels of the inflammatory factors tumor necrosis factorα(TNF-α)and interleukin 1β(IL-1β)in intestinal tissues and intestinal fatty acid-binding protein(I-FABP)in heart blood were measured.The levels of enzyme-linked immunosorbent assay and Western Blot assay were performed to detect the key protein of nuclear factorκB(NF-κB)pathway.Results The intestinal mucosal injury scores in the sham-operation,model,low-dose and high-dose experimental groups were 0.20±0.42,4.40±0.52,3.20±0.63 and 2.00±0.47;the intestinal wet/dry weight(W/D)ratios in these four groups were 2.01±0.35,5.89±1.23,4.31±0.77 and 3.27±0.53;TNF-αlevels in the gut in these 4 groups were(476.57±121.37),(884.97±193.46),(665.16±142.09)and(498.33±135.21)pg·g^(-1);I-FABP levels in the heart blood were(1.97±0.45),(4.33±1.87),(2.87±0.74)and(2.06±0.31)ng·mL^(-1);Toll-like receptor-4(TLR4)protein expression levels in these four groups were 1.00±0.20,3.21±0.71,2.21±0.57 and 1.03±0.22;the ratio of p-NF-κB p65/NF-κB p65 protein expression levels were 0.52±0.11,3.75±0.55,2.52±0.47 and 0.42±0.17;the above indexes were statistically significant when comparing the model group with the sham-operation group,the low and high experimental dose groups with the model group,and the low dose experimental group with the high dose experimental group(all P<0.05).Conclusion DEX pretreatment provided effective protection against intestinal I/R injury,which can be attributed to the anti-inflammatory effect mediated through inhibition of TLR4/NF-κB signaling pathway.