Agomelatine Ameliorates Cognitive and Behavioral Deficits in Aβ-Induced Alzheimer's Disease-like Rat Model

Background and Objectives: Alzheimer's disease (AD) has become a serious health problem. Agomelatine (Ago) is a neuroprotective antidepressant. This study aimed to assess how Ago influences behavioral outcomes in AD-like rat model. Materials and Methods: Forty-eight Wistar albino rats were allocated into four groups: Control (C), Alzheimer's disease-like model (AD), Alzheimer's disease-like model treated with Ago (ADAgo), and Ago alone (Ago). Physiological saline was injected intrahippocampally in C and Ago animals, whereas Aβ peptide was delivered similarly in AD and ADAgo rats. On day 15, 0.9% NaCl was administered to the C and AD groups, and Agomelatine (1 mg/kg/day) was infused into ADAgo and Ago rats via osmotic pumps for 30 days. Behavioral functions were evaluated using Open Field (OF), Forced Swim (FST), and Morris Water Maze (MWM) tests. Brain tissues were examined histopathologically. Neuritin, Nestin, DCX, NeuN, BDNF, MASH1, MT1, and MT2 transcripts were quantified by real-time PCR. Statistical analyses were performed in R 4.3.1, with p < 0.05 deemed significant. Results: In the FST, swimming, climbing, immobility time, and mobility percentage differed significantly among groups (p < 0.05). In the MWM, AD rats exhibited impaired learning and memory that was ameliorated by Ago treatment (p < 0.05). DCX expression decreased in AD rats but was elevated by Ago (p < 0.05). Nestin levels differed significantly between control and AD animals; MT1 expression varied between control and AD cohorts; and MT2 transcript levels were significantly lower in AD, ADAgo, and Ago groups compared to C (all p < 0.05). Conclusions: Ago exhibits antidepressant-like activity in this experimental AD model and may enhance cognitive function via mechanisms beyond synaptic plasticity and neurogenesis.