Basal Synthesis of Heat Shock Protein 70 Increases with Age in Rat Kidneys

The heat shock protein (HSP) system is a mechanism of cell defense induced by stress, constitutively expressed during basal conditions and essential to the maintenance of cellular integrity. Acutely induced HSP synthesis decreases with aging, but the effect of age on the basal expression of HSP70 has not been specifically addressed so far. The aim of this work is to study the age-dependent basal concentrations of HSP70 mRNA in rat kidneys. In 8 young (2–3 months), 6 adult (6–11 months) and 6 old male Wistar rats (22–27 months), steady-state concentrations of HSP70 and γ-actin mRNA and of rRNA were measured. Pentosidine was measured by HPLC. The basal, unstimulated HSP70 mRNA is increased in young and old rats compared with adult subjects [young: 182% of adult levels (100–299), old: 167% of adults (142–209); p