Terephthalic Acid Induced Bladder Lesion

Terephthalic acid (TPA), one of the most commonly produced chemicals in the world, had been extensively used for the synthesis of certain crystalline polyester resins, films, and fibers. With the increasing of the TPA production, there is great number of occupational workers. The manifestation of the toxicity for baby ctenopharyngodon idellus and the induction of bladder stone, epithelial cell proliferation and ultimately carcinomas raise increasingly conern regarding TPA as a nongenotoxicity chemical. To elucidate the mechanisn of TPA induced bladder lesion and provide more information for rationally evaluating the potential risks of TPA, we studied the effects of TPA on rat bladders after 90-day TPA exposure and also investigated the relationships among bladder stone, bladder hyperplasia and the chemical itself.Part I. Induction of Bladder Lesion by Terephthalic Acid andIts MechanismObjective: To provide more information for rationally evaluating the potential risks of terephthalic acid (TPA), we studied the effects of TPA on rat bladders after 90-day TPA exposure.Methods: Sprague-Dawley rats were randomly divided into five groups at doses of 0%, 0.04%, 0.2%, 1% and 5%TPA respectively for 90-day subchronic feeding study. Urine, serum, brain, liver, lung, kidney, bladder and other tissues were collected and analyzed.Results: TPA decreased urinary pH and increased the contents of Ca2+, Zn2+, Mg2+, Na+ and K+ in urine. 24hr urinary volume was significantly increased in male rats in 1% and 5%TPA group. Urinary white sediment was found in both male and female rats. The formation in male rats seemed to be more susceptible than that of female. Alpha 2u-globulin (AUG) levels in serum and urine of male rats were significantly increased with a dose-dependent manner. 15 cases (14/52 in male rats and 1/23 in female) of hyperplasia (simple or atypical) were determined in 5%TPA group, of which 3 cases of male rats did not accompany with bladder stone or calculus. Urinary white sediments were found in the cases of both bladder stones and hyperplasia.Conclusion: The appearance of white sediment resulted from elevated urine AUG is the basis of the formation of TPA induced bladder stone, which is also associated with TPA induced bladder epithelial cell proliferation. It can act as an early biomarker for detecting the potential toxic effect of TPA.