Radioprotection of the intestinal mucosa of rats by probucol

Probucol is a lipid-regulating drug that also has antioxidant properties. T his study was designed to test the possibility that probucol could provide radioprotection of the intestine when administered either intralumenally or systemically. Tissue damage was evaluated histologically by quantifying th e number of crypts per circumference and the mucosal height. Animals were s acrificed 5 days after 11 Gy of X irradiation. In one series of experiments , a loop of mid small bowel was exteriorized operatively and compartmentali zed into segments, each filled with probucol or saline. Intralumenal admini stration of probucol prior to irradiation led to a significantly greater nu mber of crypts per circumference and mucosal height compared to saline-fill ed irradiated controls. In another series of experiments, five groups of ra ts were irradiated: (1) probucol in the small bowel lumen, (2) intravenous probucol, (3) probucol by gavage, (4) probucol added to standard rat chow a nd (5) saline control. In the rats given probucol intravenously prior to X irradiation, crypt numbers and mucosal height were significantly enhanced. Probucol given by gavage also resulted in protection. Rats fed a diet conta ining probucol showed no significant protection. Topical administration was more effective than systemic. Probucol protects the intestinal mucosa from acute radiation damage when given topically, intravenously or by gavage, b ut does not do so when given as a dietary supplement. (C) 1999 by Radiation Research Society.