雷公藤甲素对内毒素致大鼠急性肺损伤的影响

目的 评价雷公藤甲素对内毒素(LPS)致大鼠急性肺损伤的影响.方法 雄性SD大鼠65只,体重200 ～ 250 g,采用随机数字表法,将其随机分为5组,对照组(C组,n=5):尾静脉注射生理盐水,同时腹腔注射1％二甲基亚砜(DMSO)；LPS组(L组,n=15)和不同剂量雷公藤甲素组(TP1～3组,n=15):尾静脉注射LPS 5 mg/kg,同时腹腔分别注射1％ DMSO和雷公藤甲素25、50、100μg/kg.于给药前1h和给药后1、3、6、12 h时行动脉血气分析；给药后12 h时心脏采血后处死大鼠,取肺组织,收集支气管肺泡灌洗液(BALF),采用ELISA法测定血清和BALF中TNF-α浓度；测定肺组织湿重(W)和干重(D),计算W/D比；光镜下观察肺组织病理学结果,并进行弥漫性肺泡损伤评分(DAD评分)；采用荧光定量PCR法测定肺组织Toll样变体4(TLR4) mRNA表达；采用Western blot法测定肺组织TLR4蛋白表达.结果 与C组相比,L组和TP1～3组给药后3、6和12 h时PaO2下降,DAD评分及W/D比升高,L组、TP1组和TP2组血清和BALF中TNF-α浓度升高,肺组织TLR4 mRNA及其蛋白表达上调,TP3组血清和BALF中TNF-α浓度降低,肺组织TLR4mRNA及其蛋白表达下调(P＜0.05).与L组和TP1组相比,TP2组和TP3组给药后6和12 h时PaO2升高,DAD评分、W/D比、血清和BALF中TNF-α浓度降低,肺组织TLR4 mRNA及其蛋白表达下调(P＜0.05).与TP2组相比,TP3组血清和BALF中TNF-α浓度降低,肺组织TLR4 mRNA及其蛋白表达下调(P＜0.05).L组和TP1组间、TP2组和TP3组间血气指标、DAD评分及W/D比较差异无统计学意义(P＞0.05).TP1～3组肺组织病理学损伤较L组减轻.结论 雷公藤甲素可减轻LPS诱发的大鼠急性肺损伤,且与剂量有关,其机制与抑制TLR4表达的上调,减少TNF-α的释放有关.

Effects of triptolide on lipopolysaccharide-induced acute lung injury in rats

Objective To investigate the effects of triptolide on lipopolysaccharide (LPS)-induced acute lung injury in rats.Methods Sixty-five male SD rats weighing 200-250 g were randomly divided into 5 groups: control group (group C,n =5),LPS group (group L,n =15),different doses of triptolide groups (groups TP1-3,n =15).In group C normal saline was injected iv and 1％ DMSO injected intraperitoneally(ip).In group L LPS 5 mg/kg was injected iv and 1％ DMSO injected ip.In groups TP1-3 LPS 5 mg/kg was injected iv and triptolide 25,50 and 100 μg/kg was injected ip respectively.Blood samples were collected at 1 h before administration and 1,3,6 and 12 h after administration for blood gas analysis.The animals were sacrificed at 12 h after administration.TNF-α concentrations in serum and bronchoalveolar lavage fluid (BALF) were determined by ELISA.The lungs were removed for microscopic examination,evaluation of diffuse alveolar damage (DAD) score and determination of W/D lung weight ratio and the expression of Toll-like receptor4 (TLR4) protein and mRNA.Results Compared with group C,PaO2 was significantly decreased at 3,6 and 12 h after administration,DAD score and W/D lung weight ratio were increased in groups L and TP1-3,TNF-α concentrations in serum and BLAF were increased,expression of TLR4 mRNA and protein was up-regulated in groups L,TP1 and TP2,whlie TNF-α concentrations in serum and BLAF were significantly decreased,expression of TLR4 mRNA and protein was down-regulated in group TP3 ( P ＜ 0.05).Compared with groups L and TP1,PaO2 was significantly increased at 6 and 12 h after administration,DAD score,W/D lung weight ratio and TNF-α concentrations in serum and BLAF were decreased,expression of TLR4 mRNA and protein was down-regulated in groups TP2 and TP3 ( P ＜ 0.05).There was no siginificant difference in blood gas parameters,DAD score and W/D lung weight ratio between group L and group TP1 and between group TP2 and TP3 ( P ＞ 0.05).Compared with group TP2,TNF-α concentrations in serum and BLAF were significantly decreased,expression of TLR4 mRNA and protein was down-regulated in group TP3 (P ＜ 0.05).The lung pathologic injury was reduced in groups TP1-3 as compared with group L.Conclusion Triptolide can attenuate acute lung injury induced by LPS in a dose-dependent manner in rats,and the inhibition of up-regulation of TLR4 expression and release of TNF-α may be involved in the mechanism.