熊果酸对脓毒症模型大鼠肺损伤的保护作用及对HMGB1/TLR4/NF-κB通路的影响

Protective Effect of Ursolic Acid on Lung Injury and Its Influence on HMGB1/TLR4/NF-κB Pathway in Septic Model Rats

目的:观察熊果酸对脓毒症大鼠肺损伤的保护作用及对HMGB1/TLR4/NF-κB通路的影响。方法:Wistar大鼠75只随机分为假手术组,模型对照组,熊果酸低剂量组(20 mg·kg^(-1))、中剂量组(40 mg·kg^(-1))、高剂量组(80 mg·kg^(-1)),每组15只。采用盲肠结扎穿孔法制备大鼠脓毒症模型,术后立即及8 h后尾静脉注射给药。造模后24 h处死大鼠,苏木精-伊红染色法评估肺组织病理学变化;ELISA法测定血清中肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)、白细胞介素-6(interleukin-6,IL-6)水平;硫代巴比妥酸比色法检测肺组织匀浆丙二醛(malonaldehyde,MDA)含量,黄嘌呤氧化酶法测定超氧化物歧化酶(superoxide dismutase,SOD)活性;Western blot法检测肺组织中高迁移率族蛋白B1(high mobility group protein B1,HMGB1)、Toll样受体4(Toll-like receptors 4,TLR4)、核因子-κB(nuclear factor-κB,NF-κB)的蛋白表达。结果:与假手术组比较,模型组大鼠肺组织中MDA、HMGB1、TLR4、NF-κB表达显著增加,SOD活性下降,血清中TNF-α、IL-1β和IL-6水平显著升高(P<0.01);与模型组比较,熊果酸各剂量组大鼠肺组织病理明显改善,MDA、HMGB1、TLR4、NF-κB表达显著降低,SOD活性升高,血清中TNF-α、IL-1β和IL-6水平显著下降(P<0.01或P<0.01)。结论:熊果酸可能通过抑制HMGB1/TLR4/NF-κB信号通路减轻炎症反应,从而发挥对脓毒症肺损伤的保护作用。

Objective: To explore the protective effect of ursolic acid on lung injury and its influence on HMGB1/TLR4/NF-κB pathway in septic model rats. Methods: 75 Wistar rats were randomly divided into sham-operation group,model group,low-dose( 20 mg·kg-1),medium-dose( 40 mg·kg-1) and high-dose( 40 mg·kg-1) ursolic acid group,15 rats in each group. A rat model of sepsis was prepared by cecal ligation and perforation. Immediately after 8 hours,the tail vein was administered intravenously.The rats were sacrificed 24 hours after model establishment,and hematoxylin-eosin staining was used to evaluate the pathological changes of lung tissue. The levels of tumor necrosis factor-α( TNF-α),interleukin-1β( IL-1β),interleukin-6( IL-6) in serum were determined by ELISA,malonaldehyde( MDA) in lung homogenate was determined by thiobarbituric acid colorimetry,and su-peroxide dismutase( SOD) was determined by xanthine oxidase method. Western blot was used to detect the expression of high mobility group protein B1( HMGB1),Toll-like receptors 4( TLR4),nuclear factor-κB( NF-κB) in lung tissues. Results: Compared with the sham-operation group,MDA,HMGB1,TLR4,NF-κB in lung tissue and TNF-α,IL-1β,IL-6 in serum increased significantly in the model group,and the activity of SOD in lung reduced significantly( P < 0. 01). Compared with the model group,the lung tissue of the ursolic acid group was significantly improved,the expression of MDA,HMGB1,TLR4,NF-κB was significantly decreased,the activity of SOD was increased,and the levels of TNF-α,IL-1βand IL-6 in serum were significantly decreased( P < 0. 01 or P < 0. 01). Conclusion: Ursolic acid may reduce the inflammatory response by inhibiting the HMGB1/TLR4/NF-κB signaling pathway,thereby exerting a protective effect on lung injury in sepsis.