Omega-3 and Omega-6 Fatty Acids Kill Thymocytes and Increase Membrane Fluidity
Aparna Prasad1, Mari Åhs§2, Alexey Goncharov1, David O. Carpenter*, 1
1 Department of Environmental Health Sciences, School of Public Health, University at Albany, Rensselaer, NY 12144, USA
2 Institute for Health and the Environment, University at Albany, Rensselaer, NY 12144, USA
Omega-3 but not omega-6 fatty acids are thought to promote cardiovascular health by increasing membrane fluidity.
The actions of acute application of omega-3 [docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic (EPA, 20:5n-3) and α-linolenic acid (ALA, 18:3n-3)] and omega-6 [docosatetraenoic acid (DTA, 22:4n-6), arachidonic acid (ARA, 20:5n-6) and linoleic acid (LNA, 18:2n-6)] fatty acids on plasma membrane fluidity and cytotoxicity were investigated using mouse thymocytes. Membrane fluidity was assessed by determining fluorescence polarization of 1, 6-diphenyl-1, 3, 5-hexatriene (DPH) and cell death was assessed by using propidium iodide (PI).
Membrane fluidity in omega-3 treated cells was significantly increased in the order of DHA>EPA>ALA, but DTA and ARA also increased fluidity and were even more potent. Both omega-3 and omega-6 fatty acids were acutely cytotoxic to thymocytes at concentrations that altered membrane fluidity, and omega-6 fatty acids caused more cell death than omega-3s.
The omega-6 fatty acids, DTA and ARA, are more potent than long chain omega-3 fatty acids in causing an increase in membrane fluidity in thymocytes.
Our results suggest that the beneficial effects of fish consumption are unlikely to be secondary to a selective action of omega-3 fatty acids on membrane fluidity.
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* Address correspondence to this author at the Institute for Health and the Environment, University at Albany, 5 University Place, A 217, Rensselaer, NY 12144, USA; Tel: 518-525-2660; Fax: 518-525-2665;
E-mail: firstname.lastname@example.org§Current Address: Linköping University School of Medicine, Linköping,