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DEVELOPMENT OF A NOVEL METHOD FOR ANALYSIS OF TRANSCRIPTIONAL CHANGES IN TRANSITIONAL EPITHELIUM FROM URINARY BLADDERS OF RATS EXPOSED TO DRINKING WATER DISINFECTION BY-PRODUCTS
Citation:
Wolf, D C. AND S D. Hester. DEVELOPMENT OF A NOVEL METHOD FOR ANALYSIS OF TRANSCRIPTIONAL CHANGES IN TRANSITIONAL EPITHELIUM FROM URINARY BLADDERS OF RATS EXPOSED TO DRINKING WATER DISINFECTION BY-PRODUCTS. Presented at Society of Toxicology, Nashville, TN, 03/17-21/2002.
Description:
Development of a Novel Method for Analysis of Transcriptional Changes in Transitional Epithelium from Urinary Bladders of Rats Exposed to Drinking Water Disinfection By- products.
Epidemiologic studies in human populations that drink chemically disinfected drinking water have consistently shown an increase in the risk of urinary bladder cancer. Specifically, increased incidences of transitional cell carcinoma of the urinary bladder is associated with consumption of chlorinated surface waters. The transitional cell epithelium is therefore the target site for chemically-induced toxicity and carcinogenicity in the urinary bladder. After chronic treatment to MX alone or a mixture of DBP's, transitional epithelial cells had marked anisokaryosis and megalokaryocytes associated with focal hyperplasia. To detect and analyze biologic events which contribute to transitional cell carcinoma, we developed a method by which only the target cell population was removed from the urinary bladder of male rats and the RNA isolated for transcriptional analysis using the Clontech TM Rat Atlas 1.2. Twelve male Long-Evans rats, 4 per group, were exposed to a mixture of potassium bromate, 3-chloro-4-
(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), chloroform, and bromodichloromethane (BDCM) administered in drinking water in a mixture of low doses of 0.02, 0.005, 0.4 and 0.07 g/L, or as a mixture of the high doses of 0.4, 0.07 , 1.8 and 0.7 g/L, respectively. In the present study, animals were exposed to deionized water or the mixture solutions for 3 weeks, then euthanized and necropsied. At necropsy the urinary bladder was instilled with 500 microliters of TrizolTM reagent, allowed to set for 7 minutes, then flushed to remove the lining cells. The amount of total RNA extracted per bladder after in situ Trizol treatment ranged from 12 to 363 micrograms. Total RNA was used to perform the cDNA array analysis which was then verified using real-time PCR, (TaqMan TM). Ths method will allow study of the biology of
the transitional epithelium of the urinary bladder and detection of altered gene expression for improved understanding and defining of biologically relevant responses to urinary bladder carcinogens.
This abstract does not reflect EPA policy.