Aging effects on circulating adiponectin levels and the expressions of adiponectin and adiponectin receptor 1 in the brains of male rats

Abstract

Summary Background At present, many studies address circulating adiponectin (APN) levels in patients with Alzheimer's disease (AD) and moderate cognitive impairment, but the results of these studies are controversial. We assumed that Alzheimer-like changes in the brain may be accompanied by the changes in APN and its receptor expression in aging process. This study sought to investigate the effects of aging on serum APN levels, APN and AdipoR1 expression in the rat brain. Methods Serum APN levels, Tau protein phosphorylation, APN and its receptor expressions in brain tissue were observed in male Sprague-Dawley rats at the age of 12 weeks (young group), 36 weeks (adult group) and 96 weeks (elder group) (n = 12). Results No significant difference in Tau5 protein expression was detected between those grops (P > 0.05). Phosphorylation of Tau at Ser262 and Ser396 was gradually increased with age in the hippocampus (P 0.05). Serum APN levels gradually reduced with age in rats (P 0.05). With age, AdipoR1 expression graduallyincreased both in the hippocampus and cerebral cortex (P Conclusion Aging can simulate Alzheimer's disease-like degeneration of the brain, with reduced circulating APN levels, decreased expression of APN and increased expression of AdipoR1 in the brains of male rats.