Study On The Mechanisms Of Carcinogenesis Of Terephthalic Acid In Vitro

Terephthalic acid (TPA), one of the most commonly used chemicals in industries of cheniical fibers, is mainly used in the production of certain ciystalline polyester resins, films and fibers. TPA has not been used for a long time in our countty, but it has developed veiy rapidly. Early studies on the toxicology of WA conducted at abroad demonstrated that the adverse effects of TPA focused on the urinaiy system, including changes in urinary ion, renal and bladder calculi, even bladder tumor, and it was believed that the tumor was the result of the mechanic stimulation induced by the stones. Recent researches made by scholars at home showed that there was no definite causality between the calculus and tumor, and no original WA was found in the stone components. On the contrary, the nitroso (NO;) and benzene ring replaced at para ?position were found in the stone. Present tests in vitro at home and abroad were confined to whether WA had genotoxic effect or not, and the great majority of scholars preferred that WA was a nongenotoxic compound. Above all, in order to investigate the carcinogenesis of original WA and its metabolites, and to provide theoretic foundation for the further study on possible mechanisms of WA inducing bladder tumor and for setting the hygiene standards of WA, we studied the effects of WA and its metabolite on the cytotoxicity, the cell transformation, the cell gap junction intercellular conmunication (GJIC), and the cell DNA 4 damage ofNlH-3T3 in this study. Part I Study on the Cytotoxicity of Terephthalic Acid to NLII-3T3 Cell In order to study the cytotoxicity of terephthalic acid (WA), MTT assay and technique of electron micrography were peifonned, the Nil-I- 3T3 cell line was selected as target cell. The cells were treated with WA at doses of 156.25,3 12.5,625,1250,and 2500ug/rnl, and the reduction of IVITT was measured at 24,48,72hours, respectively. It was found that WA ranged from 156.25 to 625ug/rnl could irritate cell growth in short time, the cell gn)wth was inhibited with the increase of exposure dose and exposure time. The electron micrography showed that the cell morphology was changed in all treated groups, including cell enlargement, vacuolization, autophagic body and myeloid change, and kaiyokinesis phase was also increased when the treated dose reached 625ug/ml. The cytotoxicity is of some importance in the pathogenesis of bladder tumor resulted from WA.