烫伤大鼠内毒素的组织分布特点及意义

The time course and tissue distribution of endotoxin in rats after thermal injury

目的观察烫伤后肠源性内毒素的组织分布特点及其与器官功能损害的关系。方法采用大鼠35%Ⅲ度烫伤模型,分别于伤前,伤后12,24,48,72h 活杀动物。留取组织或血标本,分别检测组织内毒素的含量及器官功能指标。结果烫伤后肝、脾、肺组织内毒素含量明显增高,其中以肝组织升高幅度最大。同时,伤后血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、心肌型肌酸激酶同工酶(CK-MB)水平及肺组织髓过氧化物酶(MPO)活性均显著增高(P<0.01),且一直持续至伤后24h;而小肠组织二胺氧化酶(DAO)活性呈持续降低趋势。相关分析表明,肺、肾组织内毒素含量分别与肺组织 MPO 活性及血清肌酐(Cr)水平呈显著正相关(P<0.05)。结论烫伤早期肠道内毒素移位并聚积于局部组织中,且持续较长时间,组织内毒素在诱导器官功能损害中可能具有重要意义。

Objective To observe the time course and tissue distribution of endotoxin,and to eval- uate the potential role of local endotoxin in mediating multiple organ damage following bums.Methods Wistar rats were subjected to a 35 percent full-thickness scald injury.They were grouped according to time of sacrifice:no burn,and 12,24,48,72 hours postburn.Tissue specimens from liver,kidneys,lungs and in- testine were aseptically harvested to determine tissue endotoxin levels.In addition,blood samples were ob- tained for measurement of organ function parameters.Results It was found that endotoxin levels in liver, spleen and lungs increased markedly after thermal injury,with the highest level in liver.Meanwhile,serum GPT,COT,CK-MB levels,and pulmonary myeloperoxidase(MPO)activities markedly elevated after scald injury,reaching a maximum between 12 and 24 hours.Intestinal diamine oxidase(DAO)activities tended to decrease at various time points postburn.In addition,there were highly positive correlations between pulmonary endotoxin levels and MPO activities,and also between renal endotoxin levels and serum Cr val- ues.Conclusion Burn injury per se can result in gut-derived endotoxin translocation which is mainly dis- tributed to the liver,spleen and lungs.Endotoxin accumulated in local sites may play an important role in mediating multiple organ damage secondary to major burns.