桑色素对脂多糖诱导的小鼠急性肺损伤机制的研究

Effect of morin on LPS induced acute lung injury and its mechanism

目的观察桑色素对脂多糖(LPS)诱导的急性肺损伤(ALI)小鼠的作用及机制研究。方法将30只雄性C57B/L小鼠随机分为对照组、模型组及治疗组。通过气管插管向肺内滴注LPS(5mg/kg)的方式建立ALI模型,对照组予等量生理盐水滴入。治疗组于LPS暴露后连续3d腹腔注射桑色素40mg/kg,其余两组给予等量生理盐水。72h后处死小鼠,收集支气管肺泡灌洗液,离心后沉淀行Wright-Giemsa染色计数细胞总数、中性粒细胞数,用ELISA法测定上清液中肿瘤坏死因子α(TNF-α)、IL-1β水平;称质量并计算肺湿/干质量比;HE染色检测肺组织病理改变;Western blot法检测肺组织Toll样受体4(TLR4)、IKK和NF-κB表达水平。结果气管内滴注LPS成功复制小鼠ALI模型。模型组小鼠肺组织病理检查见明显炎性浸润、肺泡间隔增宽及出血水肿,肺湿干质量比、肺泡灌洗液中细胞总数、中性粒细胞数及TNF-α,IL-1β水平、肺组织内TLR4蛋白表达水平和NF-κB、IKK磷酸化水平均较对照组明显增高,差异有统计学意义(P<0.05);腹腔注射桑色素可明显减轻LPS引起的上述病理改变,差异有统计学意义(P<0.05)。结论桑色素能在一定程度上减轻LPS诱导的ALI炎性反应,其机制可能与抑制NF-κB激活有关。

Objective To study the effect of morin on LPS induced acute lung injury mouse model and its mechanism. Meth- ods Thirty male C57B/L mice were randomly divided into control group, LPS group and LPS＋morin group, with 10 in each group. 5 mg/kg LPS was instilled into the lung from an trachea intubation in LPS group and LPS＋morin group. Then the mice in LPS＋morin group received an intraperitoneal injection of morin （40 mg/kg） every day for the next 3 d. Others received an equal a- mount of saline. After 72 h,the mice were sacrificed. The bronchoalveolar lavage fluid （BALF） was collected and centrifuged; the sediments were stained with Wright-Giemsa for total cell and neutrophil count and the supernates were prepared for ELISA. The wet and dry weight of lung was weighed to calculate the wet/dry weight ratio. HE staining was performed to examine the pathologi- cal change of lung. Western blot was used to determined the expression of TLR4,IKK and NF-κB. Results Intratracheal instillation of LPS successfully established ALI model in mouse. LPS caused significant pathological changes including inflammatory cells infil- tration, alveolar ＂septa thickness,hemorrhage and edema. The wet/dry weight ratio, the total cell count, neutrophil count, TNF and IL-1β level in BALF, and the expression of TLR4, NF-κB, and IKK were all increased significantly （P〈0.05）, which were allevia- ted by intraperitoneal injection of morin. Conclusion Morin can dampen the inflammatory response during LPS induced ALI in mouse,which is potentially attributed to its inhibitory effect on the activation of NF-κB.