Gehan Abdel-Raouf Ahmed
National Research Centre, Egypt
Title: Synaptic membrane alterations and ROS production in aluminum-induced Alzheimer's disease rat model as probed by ATR-IR and EPR techniques
Biography
Biography: Gehan Abdel-Raouf Ahmed
Abstract
In this work we have investigated the alterations in membrane physical properties and peroxidation mediated by AlCl3 in isolated synaptosomes of rat cortical brain tissue after 21, 42 and 65 days. The potential therapeutic role of Lepedium sativum (LS) as a natural anti-inflammatory, antioxidant and as acetylcholinesterase inhibitor in treating AD was also assessed in a curative group. We adopted ATR-IR spectroscopy, electron paramagnetic resonance (EPR) spin labeling and trapping (NADPH oxidase (NOX) activity), MRI, histopathological study, and animal behavior test. The ATR-IR and EPR spectroscopy results revealed that synaptosomal membrane lipids undergo free radical attacks mainly at early stage of AD (21D ) and late 65D, due to Al toxicity. Al alters significantly the phospholipids membrane order, packing, membrane fluidity and polarity. These changes are time dependent. At late AD (42, 65D), the detected increase in synaptic membrane polarity renders the membrane hyperpolarized, that may obstacle the release of synaptic vesicles content into the synaptic cleft. Moreover, AD rats gave the lowest significant (P≤0.05) poking frequency compared to the control while curative group showed a great improvement with no significant changes between control and curative rats. MRI showed lateral ventricles dilation and brain atrophy only in the AD group. Gradual degenerative change was observed in AD cortical neurons with time; neurofibrillary tangles were appeared as magenta colored and looking like flames in the cytoplasm. In curative group, neurons looked more/or less similar to those of control. In conclusion, LS greatly restore membrane integrity and showed a promising curative effect.