D-Galactose-caused life shortening in Drosophila melanogaster and Musca domestica is associated with oxidative stress

D-Galactose causes aging acceleration in different animal models but the mechanism is unclear. In the present study, we investigated the effects of D-galactose on lifespan and oxidative stress biomarkers in the fruit fly (Drosophila melanogaster) and housefly (Musca domestica). D-Galactose was added to drinking water (20mg/ml) for housefly and to culture medium (6.5%) for fruit fly from 24h after emergence. Oxidative stress was estimated by measuring the activity of Cu–Zn-superoxide dismutase (SOD) and the levels of lipid peroxidation products, namely malondialdehyde (MDA) and lipofuscin in housefly brain (male) and in fruit fly (male and female). D-Galactose caused a significant decrease in mean lifespan (by 12.6% of male and 15.9% of female) and maximum lifespan (by 12.9% of male and 17.1% of female) in fruit fly, and also a significant decrease in mean lifespan (by 27.1% of male, 19.8% of female) and maximum lifespan (by 27.1% of male, 21.9% of female) in housefly. MDA and lipofuscin increased with age in fruit fly and in housefly brains while change of the SOD activity showed a biphasic shape with age. D-Galactose caused a significant increase in MDA and lipofuscin and decrease in SOD activity in the age-matched fruit flies and houseflies. These data indicate that D-galactose shortens the lifespan of the two different fly species and that the life shortening effect is associated with an increase in oxidative stress.This revised version was published online in October 2005 with corrections to the Cover Date.