Effect of light and dark dosing time on biological response to environmental chemicals in mice

未观察到暴露于BaP的小鼠外周血网状细胞（mnret）微核诱导频率在光照和暗剂量时间之间的任何差异。而在ZT15（暗期）时，治疗组肝脏中Fasn等脂质代谢相关基因的表达显著升高。另一方面，ENU在ZT15处理小鼠的mnret显著高于ZT3（光期）处理小鼠。治疗组骨髓细胞中p53相关基因Cyclin G1的表达在ZT3时高于ZT15时。光照期可能促进DNA修复。这些结果表明，对化学物质的毒性敏感性在光相和暗相之间是不同的。

Any differences in the frequencies of micronucleus induction in peripheral blood reticulocytes(MNRETs) of mice exposed to BaP between light and dark dosing times were not observed. However, the expression of lipid metabolism related genes such as Fasn in liver was dramatically increased in treatment group at ZT15(darkphase). On the other hand, MNRETs of mice treated with ENU at ZT15 were significantly higher than those in mice treated at ZT3 (light phase). The expression of p53-responsible genes such as Cyclin G1 in the bone marrow cells was higher in treatment group at ZT3 than that at ZT15. DNA repair might be promoted at light phase. These results suggest that toxic sensitivity to chemicals is different between the light and dark phase.