Dysregulation of Drp1 and Mfn2 is associated with reduced PSD-95, synaptophysin, and BDNF expression in a rat model of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline, synaptic dysfunction, and mitochondrial abnormalities. Mitochondrial dynamics, especially the balance between fusion and fission processes regulated by proteins like mitofusin 2 (Mfn2) and dynamin-related protein 1 (Drp1), play critical roles in neuronal health. However, the relationship between mitochondrial dynamics and synaptic integrity, and cognitive deficits remains incompletely understood. This study aimed to investigate the alterations in Mfn2 and Drp1 expression and their association with synaptic protein levels and also behavioral outcomes in a rat model of AD. Thirty adult male Wistar rats were randomly assigned to control and AD groups. AD was induced through bilateral hippocampal injection of Aβ1-42. Behavioral assessments including the Morris Water Maze, Novel Object Recognition, and Y-maze were conducted to evaluate spatial learning and memory. On day 21 post-induction, gene expression of Drp1, Mfn2, PSD-95, synaptophysin, BDNF, Bax, and Bcl2 in the hippocampus and cortex was measured using real-time PCR. Oxidative stress markers (MDA, SOD, CAT) and inflammatory cytokines (NF-κB, IL-1β) were evaluated in serum using ELISA kits. Results showed significant downregulation of Mfn2 and synaptic proteins, with increased Drp1 and Bax expression in AD rats. These molecular changes were accompanied with increase of oxidative and inflammatory markers and altered cognitive performance. In conclusion, the findings suggest that disrupted mitochondrial dynamics contribute to synaptic loss and cognitive decline in AD. Targeting mitochondrial function and neuroinflammation may represent potential therapeutic targets for AD management.