P2‐155: NEUROMODULATORY ROLE OF CHEBULINIC ACID IN THE DEVELOPMENT OF β AMYLOID OLIGOMER‐INDUCED EXPERIMENTAL DEMENTIA IN RATS

Abstract

Alzheimer's disease (AD) is the most common cause of dementia in the elderly. The main hallmarks of this disease include progressive cognitive dysfunction and an accumulation of soluble oligomers of β-amyloid (Aβ) 1–42 peptide. Chebulinic acid (ChA) has been reported to possess neuroprotective potential in various neurodegenerative models such as anxiety and depression. In the current study, the ChA was challenged against intracerebroventricular (ICV)- β-amyloid (Aβ) -induced neurotoxicity to determine its therapeutic potential in dementia. β-amyloid (Aβ) was infused bilaterally (3nmol/3 μL/icv) on day 1st and 3rd after surgery. ChA (25, 50 and 100 mg/kg/p.o) was administered from 7th day onwards up to 21st day following 1st ICV- β-amyloid (Aβ) infusion. Spatial and non-spatial memory was evaluated and terminally the animals were sacrificed and hipoocampal brain regions were used to identify biochemical and histopathologicsal alterations. Ventricular administration of β-amyloid (Aβ) in rats caused impairment in learning and memory indicating cognitive dysfunctions. The observed cognitive dysfunctions was also associated with significant alterations in hippocampal biochemistry, including elevation in oxidative stress, found to significantly shorten the latency time on the MWM and ORT which was associated with increase in oxidative stress (lipid peroxidation and nitrite), compromised antioxidant defense (reduced glutathione), neurotransmitter alteration (AChE, dopamine, noradrenaline, 5-hydoxytryptamine, Gama amino butyric acid and glutamate) and elevation in neuroinflammatory cytokine (IL-1 β, IL-6 and TNF- α) levels. The number of apoptotic neurons was increased in hippocampus tissue after ICV- Aβ administration. The histopathological studies in the brain of rats also supported that ChA markedly reduced the ICV- Aβ -induced histopathological changes and well preserved the normal histological architecture of the hippocampus. The study demonstrates the effectiveness of ChA, as a powerful antioxidant, anti-inflammatory and neuromodulatory in preventing the all these detrimental effects induced by Aβ. ChA treatment significantly prevented the ICV- Aβ -induced memory deficit by attenuating the hippocampal neuronal loss, neuroinflammation and compromised antioxidant defense and cholinergic deficit in rats. Thus, ChA may have a therapeutic value for the treatment of AD.