Effect of Gallic Acid on Dementia Type of Alzheimer Disease in Rats: Electrophysiological and Histological Studies

Introduction: To study the effect of gallic acid (GA) on hippocampal long-term potentiation&nbsp;(LTP) and histological changes in animal model of Alzheimer disease (AD) induced by betaamyloid&nbsp;(A&beta;). Methods: Sixty-four adult male Wistar rats (300&plusmn;20 g) were divided into 8 groups: 1) Control&nbsp;(Cont); 2) AD; 3) Sham; 4-7) AD+GA (50, 100, and 200 mg/kg for 10 days, orally) or vehicle,&nbsp;8) Cont+GA100, A&beta; (1&mu;g/&mu;L in each site) was infused into hippocampus bilaterally. Changes of&nbsp;amplitude and slope of LTP induced in hippocampal dentate gyrus (DG) were evaluated by high&nbsp;frequency stimulation (HFS) of perforant path (PP). Results: Data showed that LTP amplitude and area under curve significantly impaired in AD rats&nbsp;(P<0.001), while significantly improved in AD rats treated with GA (P<0.05, P<0.01). Conclusion: Current findings suggest that GA reduces neural damage and brain amyloid&nbsp;neuropathology and improves cognitive function via free radicals scavenging and inhibiting&nbsp;oligomerization of A&beta; but with no effect on healthy rats.