Protective effect of dipyridamole against lethality and lipid peroxidation in liver and spleen of the ddY mouse after whole-body irradiation

Abstract

The effects of dipyridamole on radiation damage in the mouse were investigated. Dipyridamole (i.p. 2 mg/ mouse), administered 1 h before exposure, protected against gamma-irradiation. Pretreatment significantly decreased the death rate at 30 days from 89 to 33% (p < 0.001) after 9 Gy wholebody irradiation. LD 50 at 30 days was increased from 6. 67 to 7.65 Gy in the dipyridamole pretreated group. The level of thiobarbituric acid reactive substances (TBARS) in the liver and spleen, a measure of free radical initiated lipid peroxidation, increased 155, 193, 195, and 236% of control (without irradiation) in liver, and 132, 146, 168, and 276% of control (without irradiation) in spleen on days 2, 4, 7, and 10 after 9 Gy of whole-body irradiation respectively. The TBARS levels in both liver and spleen 2 days after irradiation were reduced to 73 7 and 60 19% respectively after dipyridamole treatment (2 mg/mouse, i.p. injection 1 h before exposure). In electron microscopic studies, mitochondria and endoplasmic reticulum in the irradiated mouse liver were swollen, but otherwise appeared normal after dipyridamole treatment. These results suggest that dipyridamole has a protective effect on animal survival 30 days after 60Co gamma-irradiation and inhibits lipid peroxidationwhich is thought to play a part in the radiation injury in mouse liver and spleen.