瘦素预处理对机械通气肺损伤大鼠NLRC4炎症小体表达的影响

Effect of leptinpre treatment on expression of NLRC4 inflammasome in ventilator-induced lung injury rats

目的探讨瘦素预处理对机械通气肺损伤(VILI)大鼠NLRC4炎症小体表达的影响。方法健康雄性SD大鼠36只,体质量200~250 g,6~8周龄,采用随机数字表法分为3组:对照组、VILI模型组和瘦素组,每组12只。对照组麻醉后气管插管并保留自主呼吸;VILI模型组连接小动物呼吸机行机械通气,潮气量40 ml/kg,容量控制通气4 h;瘦素组气管插管后腹腔注射外源性重组瘦素50μg/kg,应用40 ml/kg潮气量行呼吸机机械通气4 h。机械通气结束时采集股动脉血样,进行动脉血气分析,并记录PaO_(2)。处死大鼠,收集剩余血液和支气管肺泡灌洗液(BALF),离心后用酶联免疫吸附试验检测炎症因子白细胞介素1β(IL-1β)和IL-18的浓度。取右肺上叶组织行苏木素-伊红染色,光镜下观察病理学结果,并行病理损伤评分;取右肺中叶组织计算湿/干重比值;取右肺下叶组织采用蛋白质印迹法检测caspase-1、NLRC4的表达水平。结果与对照组相比,VILI模型组和瘦素组肺损伤评分、湿/干重比值、血清中IL-18和IL-1β、BALF中IL-18和IL-1β、肺组织中caspase-1和NLRC4表达明显升高(P值均<0.01),PaO_(2)明显下降(P<0.01);与VILI模型组比较,瘦素组肺损伤评分、湿/干重比值、血清中IL-18和IL-1β、BALF中IL-18和IL-1β、肺组织中caspase-1和NLRC4蛋白表达量降低(P值均<0.05),PaO_(2)升高(P<0.05)。结论外源性瘦素预处理可明显减轻大鼠VILI,其机制可能与抑制NLRC4炎症小体活化、减轻肺组织炎症反应有关。

Objective To investigate the effect of leptin pretreatment on the expression of NLRC4 inflammasome in ventilator-induced lung injury(VILI)rats.Methods Thirty-six pathogen-free adult male SD rats,weighting 200-250 g,6-8 weeks old,were divided into three groups using a random number table:control group,VILI model group and leptin group,12 rats in each group.The rats in control group had autonomous respiration with air for four hours after being anesthetized.VILI model group received mechanical ventilation through a small animal ventilator with 40 ml/kg tidal volume for four hours.In leptin group,rats was intraperitoneally injected with 50μg/kg recombinant leptin after tracheal intubation,and received mechanical ventilation with 40 ml/kg tidal volume for four hours.At the end of mechanical ventilation,blood samples were collected from the femoral artery for arterial blood gas analysis,and PaO_(2) was recorded.The rats were sacrificed to collect remaining blood and bronchoalveolar lavage fluid(BALF).The levels of interleukin-1β(IL-1β)and IL-18 were detected by enzyme-linked immunosorbent assay.The degree of lung pathological damage was observed after hematoxylin-eosin staining under light microscope,and lung injury score was calculated.The wet/dry weight ratio of right middle lobe was calculated.The expressions of caspase-1 and NLRC4 in right lower lobe were detected by Western blot.Results Compared with control group,the pathological injury score,the wet/dry weight ratio,the concentrations of IL-18 and IL-1βin serum and BALF,the protein expressions of caspase-1 and NLRC4 in lung tissues of VILI model group and leptin group were significantly increased(all P<0.01),and PaO_(2) was significantly decreased(P<0.01).Compared with VILI model group,the pathological injury score,the wet/dry weight ratio,the concentrations of IL-18 and IL-1βin serum and BALF,the protein expressions of caspase-1 and NLRC4 in lung tissues of leptin group were decreased(all P<0.05),and PaO_(2) was increased(P<0.05).Conclusions Exogenous leptin pretreatment can significantly reduce VILI of rats,the mechanism may be related to inhibiting NLRC4 inflammasome activation and reducing the inflammatory response of lung tissues.