益生菌对体外循环致大鼠肺损伤影响研究

The effect of probiotics on the lung injury induced by cardiopulmonary bypass in rats

目的探讨益生菌对体外循环(CPB)致大鼠肺损伤的影响。方法选取30只清洁级健康雄性SD大鼠为研究对象。采用随机数字表法将其分为假手术组(S组)、CPB组(C组)和益生菌组(P组),每组各10只。CPB开始前7 d,P组每日用益生菌2 ml(含活菌数1×107 CFU)灌胃,S组和C组用生理盐水2 ml灌胃;第8天C组和P组行动静脉置管,CPB转流60 min,S组仅置管不进行CPB转流。测定各组大鼠血浆二胺氧化酶(DAO)、D-乳酸、内毒素、肿瘤坏死因子-α(TNF-α)和白细胞介素6(IL-6)水平。取腔静脉血、肝、肺、肾组织及肠系膜淋巴结,鉴定有无细菌生长及细菌种类。计算肺湿/干重比值,观察病理学变化并进行肺损伤评分。结果C组与P组大鼠D-乳酸、内毒素、TNF-α、IL-6、DAO均显著高于S组,且C组高于P组,差异均有统计学意义(P<0.05)。C组与P组细菌易位发生率高于S组,且C组高于P组,差异均有统计学意义(P<0.05)。S组大鼠肺组织结构清晰完整,未见明显异常;C组大鼠部分肺泡壁断裂、肺泡腔塌陷,可见炎性细胞、红细胞和水肿液渗出;P组大鼠肺泡间隔增宽,肺泡毛细血管扩张,少量炎性细胞及红细胞渗出。C组、P组大鼠肺损伤评分、湿/干重比值、呼吸指数明显高于S组,且C组高于P组,差异有统计学意义(P<0.05)。C组、P组大鼠氧合指数明显低于S组,且C组低于P组,差异有统计学意义(P<0.05)。结论益生菌可在一定程度上抑制肠道炎性反应,降低大鼠肠黏膜通透性和细菌易位发生率,减轻内毒素血症和炎性反应,进而减轻CPB致大鼠肺损伤,改善肺功能。

Objective To investigate the influence of probiotics in the lung injury induced by cardiopulmonary bypass(CPB)in rats.Methods Thirty healthy male SD rats were selected and divided into sham operation group(S group),CPB group(C group)and probiotics group(P group)by random number table method,with 10 rats in each group.7 days before CPB,group P was gavaged with 2 ml of probiotics daily,and group S and group C were gavaged with 2 ml of normal saline.On the 8th day,group C and group P were operated with intravenous catheterization for CPB for 60 min,while group S was only catheterized without CPB.Plasma levels of diamine oxidase(DAO),D-lactic acid,endotoxin,tumor necrosis factor-α(TNF-α)and interleukin 6(IL-6)were determined in each group.Caval blood,liver,lung,kidney tissues and mesenteric lymph nodes were collected to identify bacterial growth and bacterial species.Lung wet/dry weight ratio was calculated,pathological changes were observed and lung injury score was performed.Results D-lactic acid,endotoxin,TNF-α,IL-6 and DAO in groups C and P were significantly higher than those in group S,and those in group C were higher than those in group P,with statistical significance(P<0.05).The incidence of bacterial translocation in group C and P was higher than that in group S,and that in group C was higher than that in group P,with statistical significance(P<0.05).The lung tissue structure of rats in group S was clear and complete,and no obvious abnormality was observed.In group C,some alveolar walls were broken and alveolar cavities collapsed,and inflammatory cells,red blood cells and edema fluid exudated.In group P,alveolar septum was widened,alveolar capillaries were dilated,and a small amount of inflammatory cells and red blood cells exudated.Lung injury score,wet/dry weight ratio and respiratory index of rats in group C and group P were significantly higher than those in group S,and those in group C were higher than those in group P,with statistical significance(P<0.05).The oxygenation index of rats in group C and group P was significantly lower than that in group S,and that in group C was lower than that in group P,with statistical significance(P<0.05).Conclusion Probiotics can inhibit the intestinal inflammatory response to a certain extent,reduce the permeability of the small intestine mucosa and bacterial translocation rate,reduce endotoxemia and inflammatory response,and thereby reduce CPB-induced lung injury and improve lung function in rats.