An experiment was conducted to evaluate the effects ofcobalt radiation inhistomorphology changes in heart, brain, kidney, spleen, lung and liver of Wistar rats weighing 160 to 180 gr. A total of 100 rats were divided into 4 groups with 25 rats each.T1) First group as control group did not receive any radiation, T2) was irradiated with 6Gy, T3) was irradiated with 8Gy, T4) ws irradiated with 14Gy. Results demonstrated dosage dependent changes in different parts of the brain tissue. Histopathological studies of the central nervous system revealed radiation-induced lesions early after exposure with congestion and edema.The renal tissues were subjected to histological processing, and then studied. Histopathological studies revealed glomerular and tubular changes with infiltration of the neutrophils and other leukocytes .More irreversible changes included mesangial matrix and cell number increase in gromeruli. The muscular strings of heart were narrowed and became of atrophic which led to the gap between heart muscular strings (edema) in groups 2 and 3 while, rupture and necrosis can be seen in group 4.Areas of necrotic hepatocytes and cell swelling were seen in G3 and G4. But in the group 4severe congestion was seen. Also pathological study of spleen was showed that necrosis in some parts of the spleen in 3 exposed groups andfibrinoid degeneration in the central splenic vein in group. Studies of the lung revealed radiation-induced Edema, hyperemia can be seen in all the 3 groups and goes up as the dosage increases. Also, the thickening of alveolar walls through penetration of unicellular e.g. lymphocytes and macrophages are observed in animals of groups 3 and 4.
