Protective Effect of β-mercaptoethylamine and Mesenteric Vessel Clamping on Intestine-irradiated Rats

Summary β-mercaptoethylamine (MEA) given intraperitoneally 15 min before x-irradiation or clamping of the mesenteric vessel during x-irradiation of the exteriorized ileum and jejunum in rats reduced mortality, body-weight loss in survivors, and histological damage as compared with irradiated controls. When animals which received 1800 r and MEA were compared on a mortality and histopathological basis with those exposed to 1400 r with no drug treatment, the responses were very similar. Thus, with this method for evaluation, MEA reduced the effect of the x-ray exposure dose by about 20 per cent. MEA and clamping were not effective with x-ray exposure doses of 2200 r and above and 3000 r and above respectively. The combination of the two treatments had a substantial additive protective effect. It resulted in 67 per cent survival at the exposure dose of 3500 r where neither treatment by itself was effective, but became completely ineffective at 4500 r and above.