Gender- and region-dependent changes of redox biomarkers in the brain of successfully aging LOU/C rats

The LOU/C (LOU) rat is an obesity resistant strain with higher longevity and healthspan than common rats. The management of oxidative stress being important to successful aging, we characterized this process in the aging LOU rat. Male/female LOU rats were euthanized at 4, 20, and 29 months. Macrodissected hippocampus, striatum, parietal cortex, cerebellum were assayed for tissue concentrations of glutathione (GSH), gamma-glutamyl-cysteine-synthetase (γ-GCS), total thiols, protein carbonyls, mRNAs of clusterin and the known protective enzymes thioredoxine-1 (TRX-1), glutaredoxine-1 (GLRX-1), superoxide dismutase-1 (SOD-1). Brain levels of GSH, γ-GCS, total thiols remained constant with age, except for GSH and γ-GCS which decreases in females. Clusterin, TRX-1, GLRX-1, SOD-1 mRNA levels were maintained or increased in the hippocampus with age. Age-dependency of the markers differed between sexes, with SOD-1 and TRX-1 decreases out of hippocampus in females. Since antioxidants were reported to decrease with age in the brain of Wistar rats, maintenance of GSH levels and of protective enzymes mRNA levels in the LOU rat brain could contribute to the preservation of cognitive functions in old age. Altogether, the successful aging of LOU rats may, at least in part, involve the conservation of functional antioxidant mechanisms in the brain, supporting the oxidative stress theory of aging.