迷走神经刺激改善大鼠脓毒症诱发的肾功能损伤

Vagus nerve stimulation ameliorates sepsis-induced acute kidney injury in rat

目的评价迷走神经刺激对脓毒症大鼠肾功能的影响,并探讨其作用机制。方法随机将40只雄性SD大鼠平均分为4组:假伤组、脓毒症组、迷走神经刺激(vagus nerve stimulation,VNS)组及α7烟碱型乙酰胆碱受体(alpha7 nicotinic acetylcholine receptors,α7nAChR)拮抗剂组。假伤组大鼠仅行开腹暴露盲肠后还纳腹腔;脓毒症组大鼠行盲肠结扎穿孔术(cecal ligation and perforation,CLP)构建脓毒症模型;VNS组大鼠于CLP术后即刻予左侧颈部迷走神经电刺激20 min;α7nAChR拮抗剂组大鼠CLP术前30 min腹腔注射甲基牛扁亭(methyllycaconitine,MLA)(2 mg/kg),余操作步骤同VNS组。术后24 h检测血尿素氮、血肌酐、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白介素6(interleukin-6,IL-6)水平;收集测定24 h尿量,检测尿液中性粒细胞明胶酶相关脂质运载蛋白(neutrophil gelatinase-associated lipocalin,NGAL)、肾损伤分子1(kidney injury molecule-1,KIM-1)水平;取大鼠肾组织,行苏木精和伊红(hematoxylin-eosin,HE)染色和TdT介导的脱氧三磷酸尿苷缺口末端标志法(TdT-mediated dUTP nick-end labeling,TUNEL)染色,评估肾病理学改变和肾小管上皮细胞凋亡情况。结果①脓毒症组大鼠血肌酐、尿素氮、TNF-α、IL-6较假伤组和VNS组明显升高(P<0.01);②脓毒症组大鼠24 h尿量较假伤组和VNS组明显减少(P<0.01);③脓毒症组大鼠尿NGAL、KIM-1较假伤组和VNS组明显升高(P<0.01);④脓毒症组大鼠肾病理学损伤评分和肾小管上皮细胞凋亡计数较假伤组和VNS组明显升高(P<0.01);⑤与α7nAChR拮抗剂组相比,脓毒症组大鼠血肌酐、尿素氮、TNF-α、IL-6和尿NGAL、KIM-1以及24 h尿量、肾病理损伤评分、肾小管上皮细胞凋亡计数无统计学差异(P>0.05)。结论迷走神经电刺激通过激活依赖α7nAChR的胆碱能抗炎通路显著改善脓毒症大鼠的肾损伤。

Objective To evaluate the influence of vagus nerve stimulation on renal function in septic rats and explore its mechanism.Methods Forty male SD rats were divided into four groups:sham group,sepsis group,vagus nerve stimulation(VNS)group,and alpha7 nicotinic acetylcholine receptors(α7nAChR)antagonist group(n=10).Rats in sham injury group only underwent laparotomy to expose the cecum,and then the cecum was returned to the abdominal cavity.Sepsis rat model was constructed by cecal ligation and perforation(CLP).Rats in VNS group were given electrical stimulation on left cervical vagus nerve for 20 min after CLP.Rats inα7nAChR antagonist group were intraperitoneally injected with 2 mg/kg methyllycaconitine(MLA)at 30 min before CLP.At 24 h after CLP,serum of rats was collected to detect levels of blood urea nitrogen(BUN),serum creatinine(Scr),tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)by biochemical and enzyme-linked immunosorbent assay(ELISA).The 24 h urine volume of each rat was collected,and the 24 h urine volume per kilogram body weight of each rat was calculated.Urinary neutrophil gelatinase-associated lipocalin(NGAL)and kidney injury molecule-1(KIM-1)were analyzed by ELISA.hematoxylin-eosin(HE)staining and TdT-mediated dUTP nick-end labeling(TUNEL)staining were performed to evaluate renal histopathological changes and tubule cell apoptosis.Results①The levels of BUN,Scr,TNF-αand IL-6 of rats in sepsis group were significantly higher than those in sham group and VNS group(P<0.01).②The 24 h urine volume per kilogram body weight of rats in sepsis group was significantly lower than that in sham group and VNS group(P<0.01).③The levels of urinary NGAL and KIM-1 in sepsis group were significantly higher than those in sham group and VNS group(P<0.01).④As compared with those of rats in sham group and VNS group,the renal histological damage score and the renal tubule apoptotic cell coun of rats in sepsis group were significantly increased(P<0.01).⑤Scr,BUN,TNF-α,IL-6,urinary NGAL,urinary KIM-1,24 h urine volume per kilogram,renal histological damage score,and renal tubule cell apoptosis count in sepsis group showed no significant difference fromα7nAChR antagonist group(P>0.05).Conclusion Electrical stimulation of vagus nerve can significantly alleviate sepsis-induced acute kidney injury in rats,through the activation ofα7nAChR dependent cholinergic anti-inflammatory pathway.