Protection of Mice Against X-Irradiation by Spleen Homogenates Administered After Exposure.

Abstract

The mortality of adult LAf1 mice, exposed to whole-body X-irradlatlon in doses of 650, 700 and 800 r, was either prevented or reduced markedly following a single intraperitoneal injn. of spleen homogenate (in [image]/15 phosphate buffer at pH 7.2) administered either 1 hr. or as long as 45 hrs. after radiation exposure. The equivalent of 1 to 2 spleens was injd. into each irradiated mouse. The protective factor was present in homogenates from spleens of young mice (1-3 wks. old), and to a smaller degree in homogenates of spleens from adult mice. Of 15 mice exposed to 700 r, each of which received the equivalent of 1.3 spleens, 14 were alive at 30 days , whereas only 1 out of 10 of the control group survived. Similarly, of 14 mice exposed to 800 r, and injected with the equivalent of 1.8 spleens, 11 survived, whereas none of 11 control animals survived. The posti-irradiation protection afforded by spleen homogenate injn. was reflected in minimized wt. losses observed in the spleen-homogenate-treated mice as compared with the control animals.