How sodium arsenite improve amyloid β-induced memory deficit?

Area of Science:

• Neuroscience
• Toxicology
• Molecular Biology

Background:

• Arsenic exposure is linked to cognitive deficits, but its molecular mechanisms remain unclear.
• Understanding arsenic's impact on learning and memory is crucial for public health.

Purpose of the Study:

• To investigate the concentration-dependent effects of sodium arsenite on memory in rats.
• To explore the molecular mechanisms underlying arsenic's influence on memory, particularly in the context of beta-amyloid (Aβ) exposure.

Main Methods:

• Male rats were subjected to Pavlovian fear conditioning to assess contextual and tone memory.
• Sodium arsenite (1, 5, 10, 100nM) was administered alone and with Aβ.
• Western blot analysis was used to measure levels of caspase-3, NF-κB, CREB, HO-1, and Nrf2.

Main Results:

• High doses of sodium arsenite significantly impaired memory 9 and 16 days post-administration.
• Low doses of sodium arsenite attenuated Aβ-induced memory deficits after 16 days.
• High arsenic doses increased caspase-3 and NF-κB; low doses activated Nrf2, HO-1, and CREB phosphorylation in the hippocampus.

Conclusions:

• Sodium arsenite exhibits concentration-dependent effects on contextual and tone memory.
• Ultra-low concentrations of sodium arsenite may offer neuroprotection against Aβ-induced memory impairment.
• Neuroprotection is potentially mediated by increased Nrf2, HO-1, CREB phosphorylation, and decreased caspase-3 and NF-κB levels.