ベンゼン・ガス吸入によるマウス生態反応の系統差について

抄録

Strain difference of responses to acute and long-term benzene inhalations was investigated in male mice of CFW and ddN lines. Observed responses included mortality and lethal time by acute exposure to higher concentrations of benzene, and changes in leucocyte counts and hemoglobin levels after repeated inhalations of lower concentrations. Experiments and results are as follows. 1) Groups of mice aged 5, 7 and 10 weeks for both strains were exposed to 1.5% benzene and mortalities were observed. Mice of 5 and 7 weeks of age did not show any significant strain difference in mortalities. In 10 weeks old mice, however, mortality of ddN was significantly higher than that af CFW. When these data were so arranged that comparison of strains could be made at the same body weight levels instead of the age classes, a significant difference in mortality was found only in the heaviest group of mice, ddN being higher than CFW. 2) Mice of the both strains were exposed, at 10 weeks of age, to 3% and 2% benzene and lethal time was determined for each animal. Mean lethal time of ddN was shorter than that of CFW in both concentrations and the difference was statistically significant in the case of 2%. Variances of lethal time were significantly smaller in ddN than in CFW. 3) After 20-days exposure to 200 ppm benzene, leucopenia was found only in ddN, and a decrease of hemoglobin concentration, on the contrary, was observed in CFW and not in ddN. From these results, it was concluded that the susceptibility of adult mice to the inhaled benzene of higher concentrations was greater in ddN than in CFW, and its variance was smaller in ddN than in CFW. And, consequently, it was noted that ddN was more suited for studying acute response, such as mortality or lethal time, to benzene inhalation in mice.