Not Only Melatonin but also Caffeic Acid Phenethyl Ester Protects Kidneys against Aging-related Oxidative Damage in Sprague Dawley Rats

Microscopic features and antioxidant status of kidneys of young, old, and caffeic acid phenethyl ester (CAPE) and melatonin administered old Sprague Dawley rats were evaluated. Aging-related tubular and glomerular changes were evident. The most prominent tubular alterations were massive vacuole formation, mitochondrial degeneration, and lysosome accumulation. Mean tissue malondialdehyde (MDA) level was increased, mean tissue superoxide dismutase (SOD), catalase (CAT) (p<.001), and glutathione peroxidase (GPx) activities (p<.05), and total glutathione (GSH) level were decreased in old animals. Melatonin significantly reduced tissue MDA levels (p<.005), but increased tissue SOD (p<.001), CAT, and GPx activities (p<.05), and GSH levels (p<.005) in old animals. CAPE also significantly reduced tissue MDA levels (p<.005), but increased tissue SOD (p<.05), CAT (p<.005), GPx activities, and GSH levels (p<.001) in old rats. Mean tissue MDA levels of melatonin and CAPE-administered rats were even lower than those of young rats (p<.05). In conclusion, tubular and glomerular structures and tissue antioxidant enzyme activities were very well preserved in CAPE and melatonin-administered rats.