N-acetylcysteine slows down ageing and increases the life span of Drosophila melanogaster.

Ageing can be defined as the time-dependent decline of physiological functions of an organism. The molecular causes for the ageing process are multiple, involving both genetic and environmental factors. It has been proposed that antioxidants may positively influence the ageing process, protecting the organism against free radical-induced damage. Here we show that the antioxidant N-acetylcysteine (NAC) has a life-extending effect on Drosophila melanogaster. Dietary uptake of NAC results in a dose-dependent increase in median and maximum life span. Flies fed on 1 mg/ml NAC food live 16.6% longer; at 10 mg/ml, life span increases by 26.6%. We have examined the effect of NAC treatment on protein and RNA levels: we observe an NAC-dependent increase in absolute amounts of total RNA and ribosomal RNA, but no differences in protein levels. The NAC effect on longevity may involve differential expression of specific mRNA genes, as suggested by RNA finger-printing experiments.