内毒素/脂多糖对烫伤大鼠休克期肝脏脂肪代谢的影响

The influence of lipopolysaccharide on adipose metabolism in liver during shock stage of scalded rats

目的观察内毒素/脂多糖(LPS)对烫伤大鼠休克期肝脏脂肪代谢的影响。方法采用30%TBSAⅢ度烫伤大鼠模型,随机分为单纯烫伤组(烫伤组)和烫伤后LPS攻击组(攻击组),另设假烫对照组(对照组),每组20只。攻击组大鼠于烫伤后2h腹腔注射LPS,3.0mg/kg.伤后24、48h分别检测3组大鼠血浆LPS、肿瘤坏死因子(TNF)α、游离脂肪酸(FFA)含量和肝组织内腺苷三磷酸(ATP)、甘油三酯(TG)及丙二醛(MDA)含量,并进行肝组织形态学观察。结果对照组大鼠假烫后24、48h,血浆FFA水平分别为(0.4±0.3)、(0.5±0.3)mmol/L,烫伤组分别为(0.9±0.3)、(1.2±0.5)mmol/L,攻击组大鼠伤后增加至(2.3±0.3)、(2.5±0.4)mmol/L,后两组之间比较差异有统计学意义(P<0.01).伤后48h,烫伤组和攻击组的肝组织TG含量分别为(242±27)mmol/g和(530±30)mmol/g,ATP含量分别为(6.0±2.4)μmol/g和(1.7±0.5)μmol/g,组间比较差异有统计学意义(P<0.01).组织形态学检查见,烫伤组大鼠肝细胞脂肪变性和线粒体损伤程度明显轻于攻击组,对照组肝细胞形态正常。结论烧伤后早期LPS打击可引发脂源性能量利用障碍,并加剧肝脏脂肪变性。

Objective To investigate the influence of lipopolysaccharide （LPS） on adipose metabolism in liver during shock stage of scalded rats. Methods Sixty adult Wistar rats were inflicted with 30% TBSA full thickness scald and were randomly divided into 3 groups： i.e. sham group （control, n = 20） , simple scald group [ （ n=20） and LPS group （ n=20, with intra-peritoneal injection of 3.0 mg/kg LPS at 2 postscald hour （PSH） ]. The contents of LPS, tumor necrosis factor α （TNF-α） , free fatty acids （FFA） in plasma and adensine triphophate （ATP） , triglyceride （ TG ） , malonaldehyde （ MDA ） in liver in each group were determined at 24 and 48 PSH. The histological changes in hepatic tissue in each group were also observed. Results The plasma contents of FFA in LPS group at 24 and 48 PSH were 2.3 ± 0.3 mmol/L and 2.5 ±0.4 mmol/L, respectively, which were obviously higher than those in control（0.4 ± 0.3 mmol/L, 0.5 ±0.3 mmol./L） and scald（0.9 ±0.3,1.2 ±0.5 mmol/L, P 〈0.01） groups. Meanwhile, there was obvious difference in the contents of TG and ATP in liver between LPS group（TG： 530 ± 30 mmol/g, ATP： 1.7 ±0.5μmol/g） and scald group （TG： 242 ±27 mmol/g,ATP：6.0 ±2.4μmol/g, P 〈0.01）. Pathological examination revealed that adipose denaturalization and injury to mltochondria in hepatocytes in scald group were significantly milder than those in LPS group. The morphology of hepatocyte in control group appeared normal. Conclusion LPS challenge to burn subjects could induce impairment in utilizing fat derived energy, and it would aggravate adipose denaturalization in the liver.