THE EFFECT OF DIFFERENT TYPES OF FLUORESCENT LIGHTING ON REPRODUCTION AND TUMOR DEVELOPMENT IN THE C3H MOUSE

Abstract— The effect of three different fluorescent lighting systems on the growth, reproduction, and lifespan of the C₃H/HeN(MTV) mouse has been investigated. The mice were born, weaned, and paired under luminaires containing daylight-simulating (DS; 425 μW/cm²), cool-white (CW; 425μW/cm²) or pink (PK; 234 μW/cm²) fluorescent lights. At the end of the study (19 months), 97% of the females in the DS and CW groups and 100% of females in the PK group had developed mammary tumors. The median times for mammary tumor development were 51 weeks (DS), 47 weeks (CW) and 42 weeks (PK) The median age of the dam at first litter and the median time between the first and second litters were not significantly different for the three lighting conditions. However, there was some evidence that the first litter was significantly delayed in both the CW and PK groups compared to the DS group. There were no significant differences in the total number of litters/dam, the total number of pups/dam, the neonatal mortality of the pups (at birth or weaning), the weights of the pups at weaning or the sex ratios among the three lighting groups. The growth of the male mice was the same under all three lighting conditions. The observed differences in tumor latency and reproduction, between female mice exposed to the DS and CW fluorescent lights, may be related to the different spectral energy distributions of these lighting systems since their irradiances were the same.