Effect of Route of Trihalomethanes (THM) Administration on Renal Toxicity in Male Rat

Single non-lethal doses of chloroform $(CHCL_3)$ dichlorobromomethane $(CHCL_2Br)$, dibromochloromethane $(CHCIBr_2)$, or bromoform $(CHBr_3)$ were administered to male rats. Routes of exposure including single intraperitional (ip) and subcutaneous (sc) injection were used in order to permit comparison of severity of THM effects and renal toxicity was assessed at varied times following treatment. On an equimolar basis, sc administration of $CHBr_3$ (either 12 or 3 mmoles/kg) is more effective at increasing KW/BW than ip $CHCI_3$ treatment. Plasma urea nitrogen (BUN) following ip THM injections are markedly increased with all four THM at 24 hours post treatment. BUN response to $CHCL_2Br$ and $CHCIBr_3$-effected BUN levels have essentially returned to those of vehicle control. THM sc treatment results in a BUN response similar to that seen following ip treatment, with only the time course being different. With the exception of $CHCL_3$, sc and ip-treatments appear to be equally effective in evoking absolute BUN elevations. These results suggest that THM administration induce renal toxicity dependent upon the route or exposure.