Abstract
In order to investigate the effects of toluene exposure on blood and organs of rats with respect to the concentration and the duration, the following experiments were made. Donryu strain male rats were used as the experimental animals. The exposure with low concentrations, i.e. 100 ppm or 200 ppm toluene vapour, was 8 hours a day, 6 days a week, for one year. Examinations were carried out with respect to peripheral blood, liver function, and testes. And the weight of various organs was measured. The exposure with high concentrations was carried out at 2000 ppm toluene vapour for 10, 18 or 43 weeks. And various organs were weighed and examined histopathologically after the exposure. The results of the examination of peripheral blood and liver function are: (1) In 100 ppm and 200 ppm groups appearance ratio of Mommsen's toxic granules tends to increase in linear proportion to the exposed concentration of toluene. (2) In 200 ppm group Leucoindex (N/L <no. of neutrophils against no. of lymphocytes>ratio) tends to decrease. (3) No change in erythrocyte counts and leucocyte counts and (4) No change in serum total protein and choline-esterase activity (Table 2). As to the weight of organs in 2000 ppm group, those of liver and kidneys increased each time after the exposure and those of adrenals increased only at the early stage. The weight of thymus and spleen tended decrease from the beginning and had decreased remarkably at the 43rd week of exposure (Fig.1). In 100 ppm and 200 ppm groups, the weight of testes decreased markedly, while that of liver tended to decrease anyhow, and that of heart increased (Fig.2). As to the histopathological findings, many hyaline droplets were found in the renal tubules in 2000 ppm group. The longer the duration, the more and the larger the hyaline droplets (Photo. 1 and 2). The histopathological findings of the testes in 100 ppm, 200 ppm and the control groups were: degeneration of germinal cells in four animals (33%) of 200 ppm group (Photo. 3, 4, 5 and 6).
