A Search for Mitochondrial Damage in Alzheimer's Disease Using Isolated Rat Brain Mitochondria

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that affects regions of the brain that control cognition, memory, language, speech and awareness to one's physical surroundings. The pathological initiation and progression of AD is highly complex and its prevalence is on the rise. In his study, Alzheimer's disease was induced with single injection of amyloid-beta (A beta) peptides (30ng, by stereotaxy) in each hemisphere of the Wistar rat brain. Then memory dysfunction, oxidative stress and apoptosis induced by A beta peptide were investigated on isolated brain mitochondria obtained from infected rat. Our results showed memory impairment in rats after receiving an A beta peptide. We also found significant rise (P<0.05) at ROS formation, mitochondrial membrane depolarization, mitochondria swelling, cytochrome c release and significant decrease in ATP/ADP ratio on mitochondria isolated from brain of these memory impaired rats compared with those of untreated control rat group. Activation of caspase-3 the final mediator of apoptosis in the brain homogenate of the memory impaired rats was another justification for occurrence of neuron loss in the experimental model of AD. Our results suggest that oxidative stress and mitochondria mediated apoptosis in brain neurons play very important role in initiation of AD.