百草枯中毒大鼠肾组织细胞间黏附分子-1表达及褪黑素的作用

The expressions of intercellular adhesion molecule-1 in renal tissue of rats with paraquat poisoning and the effect of melatonin

目的观察百草枯（PQ）中毒大鼠肾组织中细胞间黏附分子-1（ICAM-1）的表达及褪黑素（MT）的作用。方法健康成年SD大鼠90只随机分对照组、染毒组及MT治疗组，每组30只。染毒组及MT治疗组一次性给予50mg／kgPQ灌胃染毒后，MT治疗组立即给予MT 10mg／kg腹腔注射，1次／d；染毒组每日给予等量生理盐水腹腔注射。每组分别于染毒后1、3、5、7、14d各取6只大鼠，观察各组肾组织病理及超微组织结构变化，免疫组化法检测大鼠肾组织中ICAM-1的表达。结果染毒组1d时肾小管上皮细胞水肿，空泡变性，随时间延长而加重；5d时达顶峰，肾小管上皮细胞重度水肿、坏死。肾小球改变相对轻微，仅为肾小球扩张充血。与染毒组相比，MT治疗组病理变化明显减轻且减轻趋势明显。染毒组肾小管上皮细胞内线粒体肿胀、嵴消失，线粒体膜破裂；MT治疗组肾小管上皮细胞内线粒体肿胀减轻。染毒组ICAM-1主要表达在肾小管上皮细胞，染毒组1、3、5、7、14d大鼠肾组织免疫组化评分分别为0．1561±0．0295、0．2572±0．0259、0．3028±0．0153、0．2083±0．0227、0．1309±0．0059，明显高于对照组，差异均有统计学意义（P〈0.01）；MT治疗组1、3、5、7、14d免疫组化评分分别为0．1259±0．0061、0．2109±0．0280、0．2679±0．0233、0．1771±0．0186、0．0791±0．0135，均明显低于染毒组，差异均有统计学意义（P〈0．01）。结论ICAM-1参与了PQ中毒大鼠肾损伤的发病过程；MT对PQ中毒肾组织有保护作用，可能是通过抑制ICAM-1起作用。

Objective To study the mechanism of paraquat （PQ）-induced renal injury in rats,the expression changes of ICAM-1 to assess the protective effect of Melatonin in PQ poisoning. Methods Ninety adult healthy Sprague-Dawley （SD） rats were divided into three groups at random.Control group： 30 rats ; Poisoned group：30 rats;Melatonin group： 30 rats. Control group and Poisoned group were treated intragastrically with 1 ml of PQ （50 mg/kg） diluted with normal saline. Control groupwere treated with the same dose of normal saline as Poisoned group and Melatonin group. Melatonin group were given 1 ml of Melatonin at a dose of 10 mg/kg diluted with normal saline （once daily, intraperitoneally） Control and Poisoned group were treated with the same dose of normal saline （once daily, intraperitoneally） as Melatonin group. Pathology of renal tissue were oberserved by HE staining, and electron microscope. The histopathological changes and the expression of ICAM-1 were observed with mmunohistochemistry （IHC）. Results （1） There were no obvious pathological changes in Control group. Poisoned group Renal glomerulus had hyperemia and distension.Renal tubule epithelial cell had edema and vacuolar degeneration and renal tubule lumina was narrowing on day 1, There were serious edema exudation and necrosis on day 5,which gradually lessened furthermore ;Compared with Poisoned group,the aforementioned pathological lesion was more palliative in Melatenin group. （2） No obvious abnomal changes in ultrastructure of renal tissues in Control group. There were swelling of mitochondrion and rupture of renal tubule epithelial cell and endoplasmic reticulum had extension, lysosome was muh and had much phagocytosis in Poisoned group. （3）There was a very weak expression of ICAM-1 in Control group, while in Poisoned group, there was already a significant higher expression of ICAM-1 of renal tubule on day 1 after PQ poisoning, Immunohistochemistry score （IHS） of Poisoned group on day 1,3,5,7,14 were （0.1561±0.0295, 0.2572±0.0259, 0.3028±0.0153,0.2083±0.0227, 0.9309±0.0059）, compared with Control group （P〈0.01）; Melatonin group were （0.1259±0.0061,0.2109±0.0280,0.2679±0.0233,0.1771±0.0186,0.0791±0.0135）, compared with Control group （P〈0.01）, compared with Poisoned group （P〈0.05） ; Conclusion ICAM-1 was involved in the procedures of renal injury;MT surely had a protective effect,which might be mediated by ICAM-1 in the paraquat-induced renal injury ,but its regulation path still need a further exploration.