内源性硫化氢抗氧化作用对乙酸溃疡性结肠炎模型小鼠黏膜损伤的影响

Effect of endogenous hydrogen sulfide on acetic acid-induced ulcerative colitis in mice

目的探讨内源性硫化氢(H_2S)对乙酸诱导的小鼠溃疡性结肠炎的影响。方法健康昆明小鼠40只,随机分为4组:对照组、模型组、硫氢化钠(Na HS)组、DL-炔丙基甘氨酸(PAG)组。小鼠禁食12 h后,模型组、Na HS组及PAG组给予单次8%的乙酸0.15 m L灌肠建立小鼠溃疡性结肠炎模型。灌肠后24 h,Na HS组、PAG组分别腹腔注射H_2S供体Na HS(50μmol/kg)及胱硫醚-γ-裂解酶(CSE)抑制剂PAG(10 mg/kg),并对小鼠的疾病活动指数(disease activity index,DAI)进行评估。3 d后处死小鼠,取结肠组织进行大体和病理学损伤评分,生化法检测病变结肠组织中的丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)及血清H_2S,ELISA法检测结肠组织血红素加氧酶1(HO-1)、醌NADH脱氢酶1(NQO1),Western印迹法检测结肠组织CSE的表达。结果与对照组相比,模型组、Na HS组、PAG组的DAI及大体、病理学损伤评分和病变结肠组织MDA含量均增高(P<0.05),Na HS组较模型组降低(P<0.05),PAG组则高于Na HS组及模型组(P<0.05)。PAG组血清H_2S含量及结肠CSE表达量均低于其他3组(P<0.05)。相较于对照组及Na HS组,模型组血清H_2S含量降低(P<0.05),结肠CSE表达量升高(P<0.05)。模型组结肠组织HO-1、NQO-1、GSH含量和SOD活力均低于对照组(P<0.05),Na HS组则显著高于对照组(P<0.05),PAG组低于Na HS组及模型组(P<0.05)。结论在乙酸诱导的溃疡性结肠炎模型中,H_2S可抑制小鼠的肠黏膜损伤,其机制可能与H_2S上调抗氧化酶有关。

Objective To investigate the effect of endogenous hydrogen sulfide（ H2S） on acetic acidinduced ulcerative colitis in mice. Methods Forty Kunming mice were randomly divided into control group,model group,sodium hydrosulfide（ NaHS） group and DL-propargylglycine（ PAG） group.The ulcerative colitis model was induced by a single enema of 8% acetic acid（ 0.15 mL） after 12 h of fasting. The H2S donor NaHS（ 50 μmol/kg）,Cystathionine-γ-lyase（ CSE） inhibitor PAG（ 10 mg/kg） and normal saline were intraperitoneally injected in mice of NaHS group,PAG group and model group 24 h after modelling,respectively; and the disease activity index（ DAI） score was evaluated.The animals were sacrificed after 3 d,the macroscopic damage score and the pathological damage score of colon lesion tissues were assessed. The malondialdehyde（ MDA）, superoxide dismutase（ SOD） and glutathione（ GSH） in colon lesion tissue and H2S contents in serum were measured with biochemical methods; and the hemeoxygenase-1（ HO-1）,NADH dehydrogenase quinone 1（ NQO-1） in the colon lesions were measured by the ELISA kits. The expressions of the CSE in colon lesion was detected by Western blotting. Results Compared with the control group,the DAI scores,the macroscopic damage score,the pathological damage score,and the content of the MDA in the model group,NaHS group and PAG group were significantly increased（ P〈0. 05）,while those in NaHS group were lower than those in model group（ P〈0. 05）,and those in PAG group were significantly higher than those in NaHS and model groups（ P〈0. 05）. The contents of the serum H2S and the expression of CSE in the colon tissues of PAG group were significantly lower than those in other three groups（ P〈0. 05）. Compared with the control group and NaHS group,the serum H2S level in the model group were decreased（ P〈0. 05）,while expression of the CSE in the colon tissues was increased（ P〈0. 05）. The contents of HO-1,NQO-1,GSH and SOD activity in the model group were significantly lower than those in control group（ P〈0. 05）,while those in NaHS group were significantly higher than those in control group（ P〈0. 05）,and those in PAG group were significantly lower than those in NaHS and control groups（ P〈0. 05）. Conclusion The endogenous H2S can inhibit the intestinal mucosal injury in mice with acetic acid-induced ulcerative colitis,which may be related to its enhancing effect on antioxidant enzyme activity.