穿心莲内酯对克雷伯杆菌肺炎大鼠肺脏病理损伤、免疫功能紊乱及TLR4/NF-κB信号通路的调节作用

Regulation of andrographolide on pathological lung injury,immune dysfunction and TLR4/NF-κB signaling pathway in klebsiella pneumoniae pneumoniae rats

目的:探讨穿心莲内酯对克雷伯杆菌肺炎的作用及机制。方法:SD大鼠随机分为对照组(Control)、模型组(Klebsiella组)、Kleb+Andro(2.5 mg)组、Kleb+Andro(5 mg)组和Kleb+Andro(10 mg)组,每组12只。气管滴入克雷伯杆菌建立大鼠肺炎模型。给药组自造模前1 d腹腔注射10 ml/kg穿心莲内酯,对照组和模型组给予等体积灭菌生理盐水,连续7 d。脱颈椎处死大鼠,取血清及肺组织检测。称量并记录大鼠右肺湿重/干重比值(W/D);HE和Masson染色检测肺组织病理形态及纤维化情况;Western blot检测裂解形式的Caspase-3和Caspase-9表达;ELISA检测血清中肿瘤坏死因子-α(TNF-α)、IL-1β和IL-6含量;RT-PCR和Western blot检测核因子-κB(NF-κB)p65和NF-κB抑制蛋白(IκBα)mRNA及蛋白表达。结果:与模型组相比,穿心莲内酯能降低W/D比值(P<0.05),减轻肺组织充血、水肿、炎症细胞浸润和胶原沉积,改善其组织形态和纤维化情况;下调凋亡相关蛋白Caspase-3和Caspase-9表达(P<0.05);抑制血清TNF-α、IL-1β和IL-6含量,及NF-κB p65和IκBα磷酸化水平(P<0.05)。结论:穿心莲内酯能抑制克雷伯杆菌肺炎大鼠的肺脏病理损伤和免疫功能紊乱,与抑制TLR4/NF-κB信号通路有关。

Objective:To investigat effect of andrographolide on Klebsiella-induced pneumonia and its mechanism.Methods:SD rats were randomly divided into Control group,Model group(Klebsiella),Kleb+Andro(2.5 mg)group,Kleb+Andro(5 mg)group and Kleb+Andro(10 mg)group,12 in each group.Tat pneumonia model was established by intratracheal instillation of Klebsiella.Medicated groups,received intraperitoneal injection of 10 ml/kg andrographolide at 1 d before model was established,control group and model group received same amount of sterilized physiological saline for 7 consecutive days.SD rats were sacrificed,serum and lung tissues were collected for detections.Weighed and recorded wet weight/dry weight ratio(W/D)of right lung tissues;HE and Masson staining were used to detect pathological morphology and fibrosis of lung tissues.Western blot was used to detect expressions of Caspase-3 and Caspase-9 in cleaved forms.ELISA was used to detect levels of tumor necrosis factor-α(TNF-α),IL-1βand IL-6 in serum.RT-PCR and Western blot were used to detect mRNA and protein expressions of nuclear factor-κB(NF-κB)p65 and NF-κB inhibitory protein(IκBα).Results:Compared with model group,andrographolide reduced ratio of W/D(P<0.05),reduced congestion,edema,inflammatory cell infiltration and collagen deposition in lung tissues,and improved morphology and fibrosis.Expressions of Caspase-3 and Caspase-9 were down-regulated(P<0.05).Contents of TNF-α,IL-1βand IL-6 in serum,phosphorylation levels of NF-κB p65 and IκBαwere inhibited(P<0.05).Conclusion:Andrographolide inhibits lung pathological damage and immune dysfunction in pneumonia rats,which is related to inhibition of TLR4/NF-κB signaling pathway.