[Effect of light deprivation on homeostasis, life span and development of spontaneous tumors in HER-2/neu transgenic mice].

Twenty five female HER-2/neu transgenic mice (FVB/N), aged 2 months, were surgically deprived of lighting; 30 intact transgenic mice, kept under standard conditions, were in control. Light deprivation was followed by inhibited intake of feed, decreased body mass and delayed age-associated estral disorders, as compared with control. Mean survival rate among experimental mice was higher by 13.5% than in control (p 0.001). Mean life span among the last surviving 10% of the experimental mice was longer than in control by 21.5% while maximum life span--by 21%. Although the number of tumor bearers under 7 months in the study group was twice that in control (p<0.05), they had almost equalized by the end of the experiment. The number of multiple malignancies and the size of tumor and metastases to the lung increased too.