硫辛酸在急性百草枯中毒致心肌损伤中保护作用的实验研究

Protective effects of lipoic acid in rats with myocardial injury induced by acute paraquat intoxication

目的:观察抗氧化剂硫辛酸对急性百草枯中毒造成的心肌损伤,心肌组织中NF-κB、NOS、NO及血中心肌酶谱的变化的影响,探讨硫辛酸对百草枯中毒所致心肌损伤的可能保护机制。方法:选择健康雄性Sprage-Dawley大鼠126只,随机分4组:正常对照组(NS)、百草枯中毒组(PQ)、百草枯+还原型谷胱甘肽组(GSH)、百草枯+硫辛酸治疗组(LA)。NS组6只;PQ组和GSH组各24只;LA组72只,再细分3个亚组,即30mg/kg、60mg/kg、100mg/kg亚组,每亚组24只。NS组给予生理盐水灌胃;PQ组给予PQ 50mg/kg灌胃;GSH组给予PQ 50mg/kg灌胃,半小时后给予GSH 200mg/kg/d腹腔注射,连续6d;LA组给予PQ 50mg/kg灌胃半小时后分亚组给予LA 30mg/kg/d、60mg/kg/d、100mg/kg/d腹腔注射,连续6d。于造模成功后1d、3d、5d、7d取大鼠相同部位的心肌组织HE染色,光镜下观察组织学变化;取另外相同部位心肌组织检测NF-κB、NOS、NO水平;腹主动脉取血检测AST、LDH、CK、CKMB水平。结果:①HE染色结果显示PQ组心肌破坏严重,心肌组织严重水肿,出血,点状坏死灶,组织间隙增宽,心肌细胞广泛肿胀、变性。GSH组在进行干预后出现上述情况较同时点的PQ组减轻。LA组在进行干预后出现上述情况较同时点的PQ组及GSH组少,心肌组织损伤轻,主要表现为局部嗜酸性变。随着LA剂量的增加,效果更加显著。②NF-κB水平、NOS的活力、NO水平:LA组与PQ组、GSH组的各相同时点对比均低,P<0.01有统计学意义;LA组各时点与NS组对比均高,P<0.05有统计学意义;随着LA剂量的增加,NF-κB水平、NOS的活力、NO水平进行性下降,各组间比,P<0.05有统计学意义。③AST、LDH、CK、CKMB水平:LA组与PQ组、GSH组的各相同时点对比均低,P<0.01有统计学意义;LA组各时点与NS组对比均高,P<0.05有统计学意义;随着LA剂量的增加,AST、LDH、CK、CKMB水平进行性下降,各组间比,P<0.05有统计学意义。结论:硫辛酸在急性百草枯中毒中能使心肌组织的损伤减轻,其机制可能是通过直接调控NF-κB、NOS、NO的水平,影响心肌组织中自由基和炎症介质的含量,从而减轻心肌水肿、出血和坏死,改善心肌细胞代谢,保护心肌组织。

Objective：To observe what mechanism lipoic acid had on myocardial injury caused by paraquat in- take. Method： 126 mal Sprage-Dawley rats were randomly divided into 4 groups：normal control one（NS, 6 rats）, paraquat poisoning one（PQ, 24 rats）, paraquat ＋ reduced glutathione treatment group one（GSH,24 rats）, and paraquat ＋ lipoic acid treatment group one（LA, 72）. For group LA, we subdivided it into three sub-groups, 30 mg/ kg（24 rats）,60 mg/kg（24 rats）, 100 mg/kg（24 rats）. 0.9% normal saline,50 mg/kg paraquat was given to NS and PQ groups by gavage respectively. 50 mg/kg paraquat was given to GSH group,200 mg/kg GSH by intraperitoneal injection half an hour later, repeat injection GSH for another 5 days. 50 mg/kg paraqua was given to LA groups, then 30 mg/kg, 60 mg/kg, 100 mg/kg LA for three subgroups respectively half an hour later, and repeat injection LA for another 5 days. Each group 6 rats killed randomly,got myocardium samples and abdominal aorta blood at same spot at 1st, 3rd, 5th, 7th day after the model was built successfully, then observe the histological changes through microscope with HE staining and determine the levels of NF-κB, NOS, NO, AST, LDH,CK,CK- MB levels. Result： ① Histological result show that myocardial cell were in edema, hemorrhage, blob-shaped focal necrosis,broadened organizing interval,and was widely swelled, degenerated in PQ group＇s group was less heavily than PQ groups at the same time points. Group LA was the least heavily in these four groups. ②In group LA,the levels of NF-κB,NOS and NO was more lower than PQ and GSH group at the same time points（P〈0.01）. For groups LA,the levels of NF-~cB,NOS and NO was higher than NS group（P〈0.05） ,and with the increasing of LA injection, the activity of these biomarkers were decreasing（P〈0.05）. ③For the levels of AST, LDH,CK,CKMB, it was lower in group LA than PQ and GSH at different time points（P〈0.01） ,but higher than NS groups（P〈0. 05）. With the increasing of LA injection, the activity of these markers were decreasing （P〈0.05）. Conclusion： Lipole acid can reduce myocardial tissue damage caused by acute paraquat poisoning, that may be directly regulate the levels of NF-κB, NOS and NO, and then affect the contents of free radicals and inflammation, then reduce myocardial edema, hemorrhage and necrosis, and improve myocardial cell metabolism.