Alzheimer's disease (AD) is the most common form of dementia and is associated with disruptions in biological rhythms regulated by clock genes within the suprachiasmatic nucleus (SCN). Altered expression of these genes may contribute to disease progression and symptom severity. Resveratrol (Res), a polyphenolic compound with antioxidant and neuroprotective properties, has been reported to alleviate AD-related impairments. This study aimed to examine the effects of Res on the expression of the clock genes Bmal1, Per1, and p53 in the SCN of a scopolamine-induced AD rat model. Thirty-six male Wistar rats were randomly assigned to four groups: control (Cont), AD, AD+ethanol (AD + Eth), and AD+Resveratrol (AD + Res). AD was induced by intraperitoneal injection of scopolamine, and histopathological confirmation was performed using Congo red staining. The mRNA expression levels of Bmal1, Per1, and p53 in the SCN were quantified by qRT-PCR, and neuronal density was assessed using Nissl staining. The expression of Bmal1 and Per1 was significantly decreased in the AD and the AD + Eth groups compared with the control group. Resveratrol treatment significantly upregulated these genes relative to both the AD and the AD + Eth groups. In contrast, p53 expression was markedly elevated in all AD-related groups, while Res significantly reduced its expression in the AD + Res group. Nissl staining showed a reduction in neuronal density in the SCN of AD rats, which was partially restored by Res. Res improved spatial learning and memory and partially restored Per1 and Bmal1 expression in the SCN, but a causal relationship was not tested.
