DIFFERENCE IN SUSCEPTIBILITY TO BENZENE AMONG RABBIT, HAMSTER, RAT AND MOUSE

In experiments on benzene poisoning various species of animals are used, and the susceptibility to benzene differs from species to species. The special qualities of experimental animals must be well characterized in order to compare experimental results and to plan future experiments. Four species of animals (rabbits, hamsters, rats, and mice) were used in the present experiment. Benzene in an olive oil mixture was injected subcutaneously into the backs of the animals for five successive days. The animals were sacrified on the sixth day of the experiment. By measuring body weight, hemoglobin content, erythrocyte count, leucocyte count, spleen weight, and thymus weight of all experimental animals, the difference in susceptibility to benzene was shown obviously. 1) In mice, a marked drop in weight of spleen and thymus, and a considerable decrease in hemoglobin content were observed. In rats, body weight, weight of spleen and thymus, and leucocyte count decreased markedly, and thrombocytosis was observed. Male hamsters usually showed decrease in thymus and body weight and thrombocytosis. Rabbits showed a great decrease in weight of spleen and thymus, and a marked leucopenia and drop in body weight. 2) Rats were the most susceptible to benzene; hamsters, the least. 3) Difference in susceptibility to benzene was observed between male and female animals. Male hamsters and male mice were more susceptible than females, but on the other hand, female rats and female rabbits were more susceptible than males