Effect of Trans-cinnamic Acid on Cognitive Deficit, Cell Density of CA1/CA3 Regions, and Cholinergic Activity of Hippocampus in Trimethylettin Model of Alzheimer's Disease

Introduction: Trimethyltin (TMT) intoxication is associated with damage to the cholinergic system in the hippocampus. The aim of this study was to evaluate the effect of trans-cinnamic acid on cognitive deficit and cell damage in CA1/CA3 regions of the hippocampus, as well as measure the activity of acetyl choline esterase (AChE) in the hippocampus of a rat model of Alzheimer’s disease (AD). Material & Methods: In this experimental study, 40 adult male Wistar rats were randomly divided into four groups: control, TMT+Saline, TMT+CIN20, and TMT+CIN40. The AD model was induced by intraperitoneal injection of 8 mg/kg TMT body weight, and 72 h after TMT administration, doses of 20 and 40 mg of trans-cinnamic acid were gavaged daily for four weeks. Subsequently, working memory, passive avoidance learning, neuronal density in hippocampal CA1 and CA3 regions, and AChE enzyme activity were measured in this study. (Ethic Code: IR.IAU.SHIRAZ.REC.1400.014) Findings: There was a significant increase in CA1/CA3 neuronal density, percentage of motor frequency, and improved passive avoidance memory in the groups receiving trans-cinnamic acid, compared to the group receiving normal saline. Moreover, AChE enzyme activity in the hippocampus, especially in the TMT+CIN40 group, increased significantly, compared to the TMT+Saline group. Discussion & Conclusion: It seems that trans-cinnamic acid with AChE inhibitory effects improves cognitive decline and hippocampal cell damage in the TMT model of AD.