Abstract
Effect of 4-hydroxynonenal (HNE), a long-chain alpha, beta unsaturated aldehyde product, generated by the oxidation of ω-6 polyunsaturated fatty acids on the sensitivity of selected neurotransmitter receptors was studied in PC-12 cells. Cytotoxicity profiling was carried out at varying concentrations of HNE (0.1–50
μM) for 30
min to 24
h. Trypan blue dye exclusion, MTT, LDH release and neutral red uptake (NRU) assays were carried out to assess the cytotoxicity of HNE. Cytotoxic response was found to be significant at 2
h of exposure. Cytotoxicity of HNE at 50
μM was exerted even at 90
min. HNE 10–50
μM was found to be cytotoxic, whereas, 2–5
μM causes physiological stress only and 1–0.1
μM non-cytotoxic. Effect on dopamine, cholinergic, serotonin and benzodiazepine receptors was studied at varying concentrations of HNE (1, 10, 25 and 50
μM for 1–8
h). A significant decrease in binding of
3H-QNB,
3H-Fluinitrazepam and
3H-Ketanserin, known to label cholinergic (muscarinic), benzodiazepine and serotonin (5HT
2A) receptors respectively was observed at 1
h exposure of PC-12 cells to HNE at 25 and 50
μM concentrations. The decrease in the binding of
3H-Spiperone, known to label dopamine (DA-D
2) receptors was evident at 4h of exposure of PC-12 cells to HNE. The decrease in the binding with DA-D
2 receptors continued till 8h. Effect on the binding of
3H-Fluinitrazepam and
3H-Ketanserin appeared to be maximum at 25 and 50
μM concentrations of HNE for 4
h and 8
h. The PC-12 cells appear to be vulnerable to cytotoxic concentrations of HNE. Experimental HNE exposure provides an intriguing model of toxicant–cell interactions involving neurotransmitter receptors in HNE neurotoxicity.