4-Hydroxynonenal disrupts zinc export in primary rat cortical cells

Accumulating evidence implicates oxidative stress in the pathogenesis of several neurodegenerative disorders including Alzheimer's disease (AD). Increased lipid peroxidation, decreased levels of polyunsaturated fatty acids, and increased levels of 4-hydroxynonenal (HNE) have been demonstrated in AD brain. Proteins responsible for zinc export are localized on the plasma membrane and may be vulnerable to damage from lipid peroxidation. To test this hypothesis, cultured primary rat cortical neurons were incubated with ⁶⁵Zn for 1 h and then treated with HNE (0-35 μM) for 4 h. Levels of ⁶⁵Zn in aliquots of medium were measured at 1, 2, 4 h following treatment with HNE and intracellular ⁶⁵Zn measured after 4 h using liquid scintillation counting. The amount of ⁶⁵Zn in medium did not differ significantly. However, a statistically significant (p < 0.05) increase of ⁶⁵Zn was observed inside cortical neurons after treatment with 20 μM HNE for 4 hours. These data suggest that HNE may impair a protein essential for zinc export leading to increased levels of intracellular zinc.