THE EFFECTS OF VINBLASTINE IN ASSESSMENT OF THE INFLUENCE OF AGE ON PROLIFERATIVE ACTIVITY OF MURINE PALATE AND FOOTPAD EPITHELIUM

Data concerning changes in the rate of cell proliferation of stratifie d epithelia with increasing age are conflicting. In the present study young (3-month-old) and old (22-month-old) C57Bl/6NNia male mice were injected intraperitoneally with 2, 3, 4 or 8 mg vinblastine sulfate/kg body weight and killed after 1.5, 3,4.5 or 6 h. The number of arreste d metaphase figures per 1000 basal cells was counted in histological s ections. Data were analysed using a multivariate analysis of variance. There was a significant difference between the accumulation of mitoti c figures in footpad epidermis and palate epithelium and both tissues contained an increased number of mitotic figures with increasing perio ds of accumulation at all dose levels. In the footpad epidermis neithe r the age of the animal nor the dose of vinblastine had a significant effect on the number of mitotic figures. In contrast, for palate epith elium the accumulation of mitotic figures was significantly less in th e old mice compared with the young mice and at a dose of vinblastine o f 2 mg/kg compared with the higher doses. There was a statistically si gnificant interaction between the dose of vinblastine and its period o f action. It was concluded that the different tissues manifest a diffe rential sensitivity to vinblastine and that only palate epithelium sho wed a significant reduction in proliferative activity with age.