目的 研究硒(Se)对肺炎支原体(MP)感染大鼠血清中环氧合酶(COX-2)、肿瘤坏死因子-α(TNF-α)的影响.方法 45只SD雄性大鼠,随机分为5组:空白对照组、模型对照组、实验A组(灌喂亚硒酸钠溶液,硒含量0.1 mg/kg)、实验B组(灌喂亚硒酸钠溶液,硒含量0.2 mg/kg)、实验C组(灌喂亚硒酸钠溶液,硒含量0.4 mg/kg),每组9只,不同浓度亚硒酸钠饲养12周后,模型对照组、实验A组、实验B组、实验C组大鼠均予MP菌液1×106 CFU/mL缓慢滴入大鼠鼻腔,共3 d,采用酶联免疫吸附试验(ELISA)方法检测MP干预后第3、7、14天大鼠血清中COX-2、TNF-α水平,并对肺组织炎症浸润程度进行评分.结果 MP感染后3、7、14 d,补充硒元素的实验A、B、C组肺组织炎性反应程度明显减轻,肺组织病理评分明显小于模型对照组,差异均有统计学意义(F=37.13、72.23、64.41,P均<0.001),实验组的炎性浸润及肺组织病理评分高峰时间大约出现在第7天,较模型对照组第14天明显缩短.MP感染第3、7、14天,实验A组、实验B组、实验C组血清谷胱甘肽过氧化物酶(GSH-Px)含量均明显高于模型对照组,差异有统计学意义(F=196.01、264.27、3 354.50,P均<0.05).与空白对照组比较,MP感染会引起血清中COX-2升高,MP接种干预第3、14天,实验A组、实验 B 组、实验 C 组血清中 COX-2 浓度明显低于模型对照组,差异均有统计学意义(F=1 321.80、875.70,P均<0.001);与空白对照组比较,MP感染会引起血清中TNF-α升高,MP接种干预第3、7、14天,实验A组、实验B组、实验C组血清中TNF-α的浓度明显低于模型对照组,差异均有统计学意义(F=955.68、7 408.61、87.18,P均<0.001).结论 Se可能参与调节MP感染后肺部的免疫炎症反应,下调MP感染后COX-2、TNF-α炎症因子的表达,减轻MP感染后肺部的炎症损伤.
Effects of selenium on the rats infected with Mycoplasma pneumoniae
Objective To observe the effects of selenium(Se)on the levels of cyclooxygenase-2(COX-2)and tumor necrosis factor-a(TNF-α)in serum of rats infected with Mycoplasma pneumoniae(MP).Methods A total of 45 SD male rats were randomly divided into 5 groups(n=9):blank control group,model control group,experiment group A(sodium selenite solution was fed with a selenium content of 0.1 mg/kg),experiment group B(sodium selenite solution was fed with a selenium content of 0.2 mg/kg),experiment group C(sodium selenite solution was fed with a selenium content of 0.4 mg/kg).After 12 weeks of feeding with different concentrations of sodium selenite,rats in model control group,experiment group A,experiment group B,and experiment group C were given MP bacteria solution 1×106 CFU/mL slowly into the nasal cavity for 3 days.Enzyme-linked immunosorbent assay(ELISA)was used to detect the levels of COX-2 and TNF-α in serum of rats at the 3rd,7th and 14th days after MP intervention,and the degree of inflammatory infiltration in lung tissue was scored.Results At the 3rd,7th and 14th days of MP intervention,the degree of inflammatory reaction in the lung tissue of the selenium supplementation groups were significantly reduced,and the pathological score of the lung tissue was significantly lower than that of the model control group(F=37.13,72.23,64.41;all P<0.001).The most severe degree of inflammatory infiltration and the maximum pathological score of lung tissue appeared on the 7th day,which was significantly shorter than that of the model control group on the 14th day.At the 3rd,7th and 14th days of MP intervention,the concentrations of glutathione peroxidase(GSH-Px)in serum of experiment group A,experiment group B,experiment group C were significantly higher than those of model control group(F=196.01,264.27,3 354.50;all P<0.05).Compared with the blank control group,MP infection could cause the increase of COX-2 in serum.At the 3rd,14th days of MP intervention,the concentrations of COX-2 in serum of experiment group A,experiment group B,experiment group C were significantly lower than those of model control group(F=1 321.80,875.70;all P<0.001).Compared with the blank control group,MP infection could cause the increase of TNF-α level in serum.On the 3rd,7th and 14th days of MP intervention,the concentrations of TNF-α in serum of experiment group A,experiment group B,experiment group C were significantly lower than those of model control group(F=955.68,7 408.61,87.18;all P<0.001).Conclusion Se might be involved in regulating the immune inflammatory response in the lungs after MP infection,which might down-regulate the expression of COX-2 and TNF-α inflammatory factors after MP infection,and reducing the immune inflammatory injury in the lungs after MP infection.
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