三聚氰胺诱发SD大鼠尿结石初步观察

Preliminary Observation on Rats Urinary Calculus Induced by Melamine

【目的】观察三聚氰胺连续给药20 d诱发SD大鼠尿结石的情况。【方法】60日龄SPF级SD大鼠190只共分为6组,5组给药组每组各34只,分别给予三聚氰胺2.5、2.0、1.5、1.0、0.5 g/kg连续灌胃;空白对照组20只,每天灌胃10 g/L甲基纤维素溶液。采用肉眼和体视显微镜观察大鼠肾脏、输尿管和膀胱形态改变,比较各组肾脏、膀胱的质量和脏器指数,观察大鼠血肌酐（CREA）、尿素氮（BUN）、尿酸（UA）、钙、磷、镁的含量变化。【结果】给药10 d各组大鼠膀胱结石发生率为9%（4/47）,给药20 d各组大鼠膀胱结石发生率为37%（11/30）,输尿管结石发生率为93%（28/30）。给药10 d和20 d各组大鼠肾脏均肿大呈灰黄色,肾内均出现条索状黄色沉淀物,部分肾脏有点状或片状出血灶。给药20 d各组肾内黄色沉淀物开始融合成片状或颗粒状,并在皮质和髓质之间形成黄色弧形光环。给药10 d和20 d各组肾脏质量和脏器指数均显著性升高,给药20 d血CREA、BUN、磷、镁含量升高（P〈0.01）。【结论】使用0.5～2.5 g/kg三聚氰胺连续给药20d,可诱发部分SD大鼠产生膀胱结石和输尿管结石,肾脏出现黄色片状或颗粒状沉淀物。

Objective To observe continuous administration of melamine for 20 days in inducing SD rats urinary calculus.Methods One hundred and ninety SPF SD rats aged 60 days were randomized into 6 groups.Five medication groups（34 rats in each group） received gastric infusion of melamine at the dosage of 2.5g/kg,2.0g/kg,1.5g/kg,1.0g/kg and 0.5g/kg respetivily.A blank control group（N=20） was also set up,given gavage of 10g/L distilled water solution of methylcellulose.The morphological changes of kidneys,ureters and bladders of rats were observed by naked eyes and under stereomicroscope.The body weight,the weight of kidney and bladder and their organ index of each group were compared.Meanwhile,the serum levels of creatinine（CREA）,blood urea nitrogen（BUN）,uric acid（UA）,calcium,phosphorus and magnesium were detected.Results The incidence of rat bladder calculus was 9%（4/47）after administration of melamine for 10 days,and was 37%（11/30）after administration for 20 days.The incidence of ureteral calculus was 93%（28/30）after administration of melamine for 20 days.The kidney was swelling with gray-yellow appearance after administration of melamine for 10 and 20 days.Meanwhile,yellow cord-like precipitates were found in the kidney.Spotty and patchy hemorrhagic foci were shown in some kidneys.The scattered yellow cord-like precipitates in kidneys melted into patch-like or granular precipitates,and a yellow arc light halo appeared between the renal cortex and medulla after administration of melamine for 20 days.The kidney weight and kidney index of rats were increased in the medication groups,and the serum levels of CREA,BUN,phosphorus and magnesium were also increased significantly（P〈0.01 compared with the blank control group）after administration of melamine for 20 days.Conclusion Continuous medication of melamine in the dose range of 0.5～2.5g/kg for 20 days can induce bladder calculus and ureteral calculus in some rats,and the yellow patch-like or granular precipitates are shown in all of the kidneys.