Therapeutic Effect of Rat Bone Marrow Injection in Rats Exposed to Lethal Whole Body X-Radiation

Abstract

A single intraven. injn. of normal homologous rat bone marrow into Sprague-Dawley rats after whole body X-ray exposure in the lethal and supralethal range (675-770 r), decreased mortality, and enhanced body wt. recovery, as compared with control irradiated rats. After injn, of 50-100 mg of marrow into rats exposed to 700 or 725 r, 70% survived the 30-day observation period, whereas none of the controls survived. At higher radiation dose levels (750 and 770 r), admn. of larger amts. of bone marrow, e. g., 200 mg./rat, was required for protection. Following 800 r exposure, admn. of bone marrow elicited no observable effect on survival, or on mean survival time even with a dose of 400 mg. marrow/rat. Mean survival time of these animals was approx. 6 days. Forced feeding of aureomycin plus sulfasuxidine to rats for 5 days following exposure to 725 r had no effect on survival; nor did this treatment enhance protective effect of bone marrow. The basis for the relatively greater effectiveness of homologous bone marrow in the mouse, than in the rat, was discussed. It was proposed that predominance of the "intestinal syndrome" (characterized by early deaths) in rats X-irradiated with dosages of the order of 800 r, and higher, may constitute the limiting factor for bone marrow therapy in this species.