对苯二甲酸诱导大鼠膀胱结石与膀胱癌的研究

为研究对苯二甲酸致癌活性及可能的致癌机理 ,对SD大鼠连续喂饲对苯二甲酸 5 0 0 0、5 0 0、5 0mg kg染毒 90天 ,对照组给予正常饲料。结果显示 ,5 0 0 0、5 0 0mg kg剂量组分别发生 10例 (10 17)和 2例 (2 18)膀胱结石 ,5 0 0 0mg kg组雄性大鼠结石发生比例明显高于雌性 ,其它组未发生结石。 5 0 0 0mg kg组发生 4例膀胱移行细胞癌 (4 17)、5例不典型增生 (5 17)和 7例单纯增生 (7 17) ;5 0 0mg kg组有 10例不典型增生 (10 18)、5例单纯增生 (5 18) ;5 0mg kg组有 10例单纯增生 (10 17) ;对照组仅发生 1例单纯增生 (1 18) ,病变情况与染毒剂量呈明显等级正相关 (Rs=0 6 9) ,但与结石的关系不明显。未发生结石的大鼠也发生上述病理改变 ,高剂量组发生 1例膀胱白斑和 1例鳞状上皮化生 ,未见鳞癌。研究提示在本次实验条件下 ,对苯二甲酸或其代谢产物对SD大鼠可能具有致癌性 ,结石的机械刺激在肿瘤的发生过程中并非起主要作用。

Study on the bladder calculi and bladder cancer induced by terephthalic acid in rats

The carcinogenicity and calculogenesis of terephthalic acid on bladder was investigated. Terephthalic acid at doses of 5000, 500 and 50 mg/kg body weight/d were administrated to SD rats for 90 days consecutively. Control animals received normal feeds. Bladder calculi were induced in 5000 mg/kg (10/17) and 500 mg/kg (2/18) group. Calculi incidence of male rats was higher than that of female rats in 5000 mg/kg dose group. Bladder transitional cell cancer (4/17), atypical hyperplasia (5/17) and single hyperplasia (7/17) could be observed in 5000 mg/kg group. Atypical hyperplasia (10/18) and single hyperplasia (5/18) could be observed in 500 mg/kg group. Single hyperplasia (10/17) could be observed in 50mg/kg group. The controls were normal except 1 case of single hyperplasia (1/18). There was a positive correlation between pathologic changes and dosage, but no significant correlation between pathologic changes and calculi incidence. Those rats without calculi produced some changes too, but no squamous metaplasia and carcinoma happened. The results suggested that under the study conditions, squamous cell carcinogenicity might be induced by terephthalic acid, and the calculi might not be the major factor inducing cancer.