黄连素对脂多糖诱导的小鼠急性肺损伤和炎症的改善作用及其机制

目的：构建内毒素（LPS）诱导的急性肺损伤（ALI）小鼠模型，探讨黄连素对ALI的保护作用及其机制。方法：40只C57BL/6小鼠随机分为对照组、LPS组、黄连素+LPS组和黄连素组，每组10只。对照组小鼠给予生理盐水，LPS组小鼠通过滴鼻给予5 mg·kg^-1 LPS 6 h，黄连素+LPS组小鼠在给予LPS的前5天灌胃50 mg·kg^-1黄连素，黄连素组小鼠给予50mg·kg^-1黄连素灌胃5 d。HE染色检测各组小鼠肺组织形态表现；检测各组小鼠肺湿干重比值；检测各组小鼠肺泡灌洗液（BALF）中总蛋白浓度和细胞渗出数；ELISA法检测各组小鼠BALF中炎性因子肿瘤坏死因子α（TNF-α）和白细胞介素6（IL-6）水平；超氧化物阴离子荧光探针（DHE）检测各组小鼠肺组织中活性氧（ROS）水平；线粒体膜电位检测试剂盒检测各组小鼠肺组织中线粒体膜电位；Western blotting法检测各组小鼠肺组织中Bcl-2和Bax蛋白表达水平，计算Bcl-2/Bax比值。结果：与对照组比较，LPS组小鼠肺间质炎性细胞浸润增加，肺泡空间增大，肺泡壁增厚，小鼠肺湿干重比值明显升高（P<0.01），总蛋白质浓度升高（P<0.05），BALF中细胞渗透数增多（P<0.01），BALF中TNF-α和IL-6水平升高（P<0.01），肺组织中ROS水平升高，线粒体膜电位降低（P<0.01），Bax/Bcl-2比值升高（P<0.01）；与LPS组比较，黄连素+LPS组小鼠肺组织炎性改变减轻，小鼠肺湿干重比值降低（P<0.05），总蛋白浓度降低（P<0.05），BALF中细胞渗透数降低（P<0.05），BALF中TNF-α和IL-6水平降低（P<0.01），肺组织中ROS水平降低，肺组织中线粒体膜电位升高（P<0.05），肺组织中Bax/Bcl-2比值降低（P<0.01）。结论：黄连素可改善LPS诱导的小鼠ALI和炎症程度，其机制可能与降低肺组织中ROS水平和保护线粒体功能有关。

Improvement effect of berberine on acute lung injury and inflammation induced by lipopolysaccharide and its mechanism

Objective: To establish the acute lung injury (ALI) mouse models induced by lipopolysaccharide (LPS),and to investigate the protective effect of berberine on ALI and its mechanism in vivo.Methods: A total of 40 C57BL/6 mice were randomly divided into control group, LPS group, berberine +LPS group and berberine group(n=10). The mice in control group were treated with saline;the mice in LPS group were treated with 5 mg·kg^-1 LPS for 6 h; the mice in berberine +LPS group were pretreated with 50 mg·kg^-1 berberine for 5 d before LPS treatment, then treated by 5 mg·kg^-1 LPS for 6 h;the mice in berberine group were pretreated with 50 mg·kg^-1 berberine for 5 d.The morphology of lung tissue of the mice in various groups were detected by HE staining. The ratios of wet to dry weights of lung tissue of the mice in various groups were detected. The concentrations of total protein and the number of effusion cells in bronchoalveolar lavage fluid(BALF) of the mice in various groups were detected; the levels of tumor necrosis factor(TNF-α) and interleukin-6(IL-6) in BALF of the mice in various groups were detected by ELISA method; the reactive oxygen species (ROS) levels in lung tissue of the mice in various groups were detected by dihydreethidium(DHE) method. The mitochondrial membrane potential in lung tissue of the mice in various groups were detected by JC-1 method.The expression levels of Bcl-2 and Bax proteins in lung tissue of the mice in various groups were detected by Western blotting method,and the ratios of Bcl-2/Bax were caculated.Results: Compared with control group, the inflammatory cell infiltration of lung interstitium and the alveolar space of the mice in LPS group were significantly increased, and the alveolar wall was thickened, the ratio of wet to dry weight of lung tissue was significantly increased (P<0.01), the level of total protein (P<0.05) and the number of exudation cells in BALF were increased (P<0.01),the levels of TNF-α and IL-6 in BALF were significantly increased (P<0.01), the ROS level in lung tissue was increased, the mitochondrial membrane potential in lung tissue was decreased (P<0.01),and the ratio of Bax/Bcl-2 in lung tissue was increased (P<0.01). Compared with LPS group, the inflammatory changes of lung tissue of the mice in berberine+LPS group were improved, the ratio of wet to dry weight of lung tissue was decreased (P<0.05), the level of total protein and the number of exudation cells in BALF were increased (P<0.05),the levels of TNF-α and IL-6 in BALF were decreased (P<0.01), the ROS level in lung tissue was decreased, the mitochondrial membrane potential in lung tissue was increased (P<0.05),and the ratio of Bax/Bcl-2 in lung tissue was decreased (P<0.05).Conclusion: Berberine could improve the degrees of LPS-induced ALI and inflammation of the mice,and the mechanism might be related to reduction of the ROS level and protection of mitochondrial function in lung tissue.