三聚氰胺对仔鼠肾脏组织结构和超氧化物歧化酶、过氧化氢酶活性及丙二醛含量的影响

Effects of melamine on histological structure and activities of superoxide dismutase,catalase and content of maleic dialdehyde in kidney of filial mice

目的观察三聚氰胺灌胃后仔鼠肾重、肾脏组织结构和超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量的变化,探讨三聚氰胺对仔鼠肾脏发育的影响。方法对160只昆明小鼠(出生7d)分别以0.3、0.8、1.3g/(kg.d)剂量的三聚氰胺和等量的生理盐水灌胃,分别于灌胃6、12、18、24、30d称量检测仔鼠肾脏的变化,用比色法测定肾脏SOD、CAT活性和MDA含量的变化,用光学显微镜观察肾脏组织结构的变化。结果灌胃18～30d后,实验组部分仔鼠肾脏水肿,颜色呈土黄色,肾重高于对照组。0.3g/(kg.d)和0.8g/(kg.d)组仔鼠肾SOD、CAT活性先升高后降低;MDA含量则先降低后升高;1.3g/(kg.d)组仔鼠肾SOD和CAT活性逐渐降低,始终低于对照组;MDA含量呈上升趋势,且始终高于对照组。随着灌胃天数的增多,实验组仔鼠肾脏皮质和髓质都有不同程度的变化,出现肾小管和集合管上皮细胞肿胀、空泡化、坏死;毛细血管扩张、充血;肾小管和集合管管腔和胞质内出现胶体样物质;肾小球肿胀、充血,肾小囊腔狭窄,肾小囊腔内出现红染性胶体样物质;细胞核染色质凝聚,细胞核降解。三聚氰胺对肾组织的影响存在剂量-时间效应。结论三聚氰胺影响仔鼠肾脏组织结构发育,这可能与肾脏抗氧化酶活性降低和丙二醛含量升高有一定的关系。

Objective To investigate the changes of kidney weight and histological structure, activities of superoxide dismutase（SOD） ,catalase（CAT） and content of maleie dialdehyde（MDA） in kidney after the developing filial mice received intragastric administration of melamine, and to evaluate the effects of melamine on kidney development of filial mice. Methods Totally 160 filial mice at the seventh day respectively received 0.3,0.8 and 1.3g/（kg＇d） doses of melamine in the three experimental groups by intragastric administration, while the control group were given the same amount of saline. The samples were harvested at day 6,12,18,24 and 30 respectively. The shape and weight of kidneys were determinded,and the activities of SOD, CAT as well as content of MDA were detected by eolorimetry. In addition, the changes of the renal lesions were observerd by optical microscope in all groups. Results At day 18-30 after the administration of melamine, kidneys of some experimental filial mice were swelling with reddish brown appearance, and the body weights were significantly higher than those of the control group. In 0. 3g/（kg.d） and 0. 8g/（ kg ~ d） group,SOD and CAT activities in kidney increased and were higher than that of the control group in the early time, then decreased and were significantly lower than that of the control group after 24 days, while MDA content in kidney decreased and lower than that of the control group in the early time,then increased and much higher than that of the control group after 24 days. In 1.3g/ （kg.d） group, SOD and CAT activities in kidney were always significantly lower than that of the control group, and MDA content was always much higher than that of the control group. With the extension of administration days, cortex and medulla of kidney of experimental filial mice appeared with some difference. The epithelial cells of renal tubule and collecting duct were swelling, vacuolization and necrosis; expansion and hemorrhage of capillary; colloid-like material appeared in the tubular and cytoplasm of renal tubular and collecting duct ; renal glomerular was swelling and congestion, and the glomerular capsule was narrow with red staining of colloid-like material; chromatin condensation and nuclear degradation. Melamine caused a dose and time-dependent effect on histological changes of kidney. Conclusion Melamine has effects on the development of organizational structure of kidney ,which might be correlated with the activities of SOD and CAT decreased and the content of MDA increased in kidney of filial mice.