谷氨酰胺对内毒素血症幼鼠肠道核因子-κB活化及肿瘤坏死因子-α、白细胞介素-6表达的影响

Effect of Glutamine on Activation of Nuclear Factor-κB and Expression of Tumor Necrosis Factor-α,Interleukin-6 in Infant Rats with Endotoxemia

目的检测内毒素血症幼鼠肠道核因子-κB(NF-κB)的活化水平及肠组织TNF-α和IL-6水平,探讨NF-κB活化与肠屏障损伤的关系,并给予谷氨酰胺(Gln)干预,探讨Gln保护肠黏膜屏障的作用机制。方法 18日龄Wistar幼鼠随机分正常对照组(NS组)、内毒素组(LPS组)和Gln干预组(Gln组)。LPS组和Gln组腹腔注射内毒素(5mg.kg-1)建立幼鼠内毒素血症模型,Gln组同时予Gln(2g.kg-1)灌胃,NS组腹腔注射等量9g.L-1盐水。LPS组和Gln组根据建模后处死时间的不同分为2h、6h、12h、24h4个亚组。观察各组动物的肠道标本光镜、电镜下的病理改变,免疫组织化学法检测其肠道NF-κB的表达,ELISA法测定其肠组织匀浆TNF-α和IL-6水平。结果 LPS组幼鼠肠道NF-κB活化水平及肠组织TNF-α、IL-6水平显著高于NS组,各亚组中以2h组为最高(Pa<0.01);与LPS组相同时间点比较,Gln组幼鼠NF-κB活化水平均显著降低(Pa<0.01),肠组织TNF-α和IL-6水平也均显著下降(Pa<0.01),肠道的病理损害亦有所减轻。结论 NF-κB的活化参与LPS介导的肠黏膜损害,而Gln对LPS肠道损伤有保护作用,其机制可能是通过抑制NF-κB活化,减少TNF-α和IL-6所致炎性损伤。

Objective To investigate the protective mechanism of glutamine（Gln）and the relationship between nuclear factor-κB（NF-κB）activation and gut barrier by detecting the activity of NF-κB and the contents of tumor necrosis factor-α（TNF-α）,interleukin-6（IL-6）of gut in infant rats with endotoxemia.Methods Eighteen-day postnatals were randomly divided into normal control group（NS group）,lipopolysaccharide group（LPS group）and Gln group.According to the survival time after injecting lipopolysaccharide,LPS group and Gln group were divided into 2 h,6 h,12 h and 24 h groups.Rats in LPS group and Gln group were injected lipopolysaccharide into abdominal cavity with a dose of 5 mg· kg-1.Rats in Gln group were given Gln（2 g· kg-1）by mouth at the same time.In the NS group,the same dose sodium chloride were injected.The pathologicl changes in the animals intestines were observed by the light microscope and the electron microscope.And the levels of TNF-α,IL-6 were detected by enzyme-linked immunosorbent assay（ELISA）and the activity of NF-κB was detected by immunohistochemistry.Results The activity of NF-κB,levels of TNF-α and IL-6 in LPS group were evidently higher than those in NS group（Pa0.01）,the peak appeared at 2 hours of activity of NF-κB and level of TNF-α,IL-6.Compared with LPS group,the activity of NF-κB,levels of TNF-α and IL-6 in Gln group were significantly decreased（Pa0.01）,and the damage of intestinal mucosa were reduced.Conclusion NF-κB participates in the intestinal damage induced by endotoxemia.Gln has a protective effect on intestine barrier induced by endotoxemia.The mechanism may involve in degrading the activtity of NF-κB and decreasing the production of TNF-α and IL-6.