血红素氧合酶1在百草枯中毒肾脏中的表达及褪黑素对其的影响

Expression of Heme Oxygenase-1 in Paraquart-Induced Renal Injury and Protective Effects of Melatonin

目的观察百草枯中毒大鼠肾组织中血红素氧合酶-1(HO-1)的表达,探讨其病理生理机制。方法 SD大鼠126只随机分为空白对照组、中毒组和褪黑素组,各42只。中毒组、褪黑素组予以百草枯(25mg/kg)腹腔注射染毒,对照组予以等量生理盐水腹腔注射,15min后褪黑素组予以褪黑素(10mg/kg)腹腔注射,对照组、中毒组予以等量生理盐水腹腔注射。于1、3、6、12h,1、2、3、5d时各组随机取6只处死。苏木精伊红(HE)染色观察各组肾组织病理学变化,采用免疫组识化学和RT-PCR观察肾组织HO-1蛋白和mRNA表达。结果①与对照组相比,中毒组染毒后3h即可见充血、水肿及空泡变性等病理变化,1d达顶峰,病理损伤评分3.30±0.31(P<0.05),其后缓解趋势不明显;而褪黑素组病理变化明显减轻且缓解趋势明显,1d时病理损伤评分2.70±0.26,与中毒组相比差异有统计学意义(P<0.05)。②与对照组相比,中毒组染毒3h在皮质部肾小管上皮细胞的细胞膜及细胞浆HO-1呈阳性表达,免疫组识化学评分(IHS)3.33±1.75,HO-1mRNA表达增强,与对照组相比差异有统计学意义(P<0.05),1d达顶峰,HIS为7.00±2.00,之后减弱,5d仍有阳性表达,但与对照组相比差异无统计学意义(P>0.05);褪黑素组HO-1表达较中毒组明显增强,IHS评分6h～3d差异具有统计学意义(P<0.05),5d不再有统计学意义(P>0.05)。结论 HO-1在百草枯中毒大鼠肾组织中呈高表达,褪黑素能明显改善百草枯中毒肾脏病理损伤,增强HO-1表达可能是其作用途径之一,而氧化损伤可能是百草枯中毒肾损伤病理生理机制之一。

Objective To investigate the expression of heme oxygenase-1（HO-1）in paraquart-induced renal injury in rats and the protective effects of melatonin,and explore possible mechanism of paraquart-induced renal injury.Methods One hundred and twenty-six adult healthy Spragne-Dawley rats were randomly divided into three groups and 42 in each group：control group（A）,paraquart group（B）,and melatonin group（C）.The rats in group B and group C were treated with paraquart（25 mg/kg）intraperitoneally,the rats in group A were treated with the same dose of normal saline.In 15 minutes,the rats in group C were given melatonin intraperitoneally at a dose of 10 mg/（kg·d）and the rats in group A and B were treated intraperitoneally with the same dose of normal saline.Six rats in each group were randomly sacrificed at one,three,12 hours and one,tou,three,five days respectively.Renal histopathological changes were observed under light microscope by HE staining.The protein and mRNA expressions of HO-1 were evaluated by immunohistochemical staining and RT-PCR respectively.Results ①In group B,there were obvious lesions in the renal tubule of cortical part,including edema,congestion and vacuolar degeneration.These pathologic changes gradually reached the peak on the first day and did not relieved till the end of this study,the pathologic injury score was 3.30±0.31,and there was a statistical significance between group B and group A（P〈0.05）.The aforementioned pathological lesion was more palliative in group C,the pathologic injury score was 2.70±0.26 at the first day;Compared with group B,there was a statistical significance.②In group A,there was no or weak expression of HO-1 and HO-1 mRNA.At the third hour,the expression of HO-1 in group B was observed in the membrane and cytoplasm of renal tubular epithelial cell of cortical part.Immunohistochemistry score（IHS）was 3.33±1.75 and the expression of HO-1 mRNA increased,there was a statistical significance between group B and group A（P〈0.05）.It reached the peak on the first day,IHS was 7.00±2.00,but there was no statistical difference between group B and group A on the fifth day（P〉0.05）;Compared with group B,the expression in group C was enhanced obviously,IHS were higher obviously on the six hour till to the third day（P〈0.05）,but there were no statistical differences on the fifth day（P〉0.05）.Conclusion The expression of HO-1 in the paraquart-damaged kidney increases and melatonin surely has an protective effect by increasing the expression of HO-1,which suggests that oxidative injury might be the main mechanism of paraquart-induced renal injury.