Methylene blue improves streptozotocin-induced memory deficit by restoring mitochondrial function in rats

Area of Science:

• Neuroscience
• Biochemistry
• Pharmacology

Background:

• Alzheimer's disease (AD) pathogenesis involves mitochondrial dysfunction, oxidative stress, and energy deficits in the hippocampus.
• Methylene blue (MB) is recognized for neuroprotective effects by enhancing mitochondrial function in neurodegenerative diseases.

Purpose of the Study:

• To investigate the efficacy of Methylene blue (MB) in ameliorating streptozotocin (STZ)-induced Alzheimer's-like dementia in a rat model.
• To determine if MB can mitigate mitochondrial dysfunction, oxidative stress, and ATP decline associated with AD.

Main Methods:

• Rats received bilateral STZ intracerebroventricular injections followed by daily MB administration (0.5mg/kg) for 7 days.
• Evaluated memory using passive avoidance tests, assessed neuronal survival and degeneration in the hippocampus (CA1 region).
• Measured oxidative stress markers (MDA, 4-HNE) and assessed mitochondrial energy metabolism (CCO activity, ATP production).

Main Results:

• MB treatment significantly improved memory deficits in STZ-induced rats.
• Preserved neuron survival and reduced degeneration in the hippocampus CA1 region.
• MB suppressed malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) levels, indicating reduced oxidative stress.
• Enhanced mitochondrial cytochrome c oxidase (CCO) activity and increased ATP synthesis were observed with MB treatment.

Conclusions:

• Methylene blue (MB) demonstrates significant therapeutic potential against Alzheimer's disease (AD) progression.
• MB effectively counteracts STZ-induced memory impairment by reducing oxidative stress and restoring mitochondrial energy metabolism.
• MB may serve as a promising agent for targeting oxidative damage and ATP synthesis failure in AD therapy.