Pharmacological Evaluation of Aescin for Neuroprotection in Intracerebroventricular Streptozotocin Model of Alzheimer’s Disease in Experimental Rats

<i>Alzheimer's disease (AD) is a neurological disorder that results in the loss of memory and cognitive functions linked to redox disbalance, neuroinflammation, neurotransmitters changes, and the accumulation of amyloid-beta (1-42) plaques in AD. In this study, rats were administered with intracerebroventricular (ICV) streptozotocin (STZ) to produce AD-like symptoms in rats. ICV-STZ bilaterally, 3 mg/kg, was infused on days 1 and 3 with the help of Hamilton syringe by fixing cannula at the target position of rat brain using coordinates -2 mm (anteriposterior), 1.6 mm Mediolateral (ML), and 1.5 mm (dorsoventral). Learning and spatial memory were checked using Morris water maze and elevated plus maze apparatus. In ICV-STZ, rats lost their spatial and learning memory, increased level of prooxidant like Lipid peroxidation (LPO), nitrite and reduced glutathione (GSH), catalase, and superoxide dismutase (SOD) level. The increased level acetylcholinesterase (AChE) catalyzed acetylcholine (ACh) concentration indicates cholinergic neuron degeneration. Furthermore, we found raised inflammatory markers and altered neurotransmitters level after ICV-STZ. Administration of aescin (10, 20, and 30 mg/kg, p.o.) dose-dependently ameliorated the behavioral alteration and inhibited inflammatory markers like tumor necrosis factor-alpha, interleukin-6 (IL-6), and IL-1β. Furthermore, aescin restored antioxidants like GSH, SOD, and catalase and reduced the nitrite and lipid peroxidation level. AChE enzyme causes degradation of ACh, and its level was declined after treatment with aescin. Aescin also restored GABA, norepinephrine, and serotonin level in the brain with prevention of raised glutamate level. Moreover, the histopathological study confirmed neuronal pathogenesis, and aescin significantly achieved neuroprotective effect via preventing neuroinflammation, balancing redox potential, and inhibiting AChE enzyme.</i>