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Effect of polyunsaturated fatty acids and antioxidants on lipid peroxidation in tissue cultures
Abstract:
Lipid peroxidation was measured by the thio-barbituric assay for malondialdehyde (MDA). A small amount of MDA was formed when medial cells from guinea pig aorta were grown in tissue culture. The polyunsaturated fatty acids 8,11,14-eicosatrienoic acid, 5,8,11,14-eicosatetraenoic acid, and 7,10,13,16-docosatetraenoic acid generated significant amounts of MDA in a time-dependent manner when they were added to cultures of medial cells and fibroblasts. MDA or its precursor remained within the cell and did not accumulate in the media. Indomethacin enhanced MDA formation from polyunsaturated fatty acid. Alpha-Tocopherol, alpha-tocopherolquinone, and 2,6-di-tert-butyl-4-methylphenol (BHT) inhibited MDA formation when a polyunsaturated fatty acid was incubated with the pro-oxidant cumene hydroperoxide. Menadione had no effect on MDA formation in the cumene hydroperoxide system. Alpha-Tocopherol and alpha-tocopherolquinone inhibited MDA formation when they were added to cells in culture. Menadione had no effect on MDA formation in tissue culture. Anti-oxidant effects which were time-dependent showed that intracellular MDA was generated from a lipid peroxide precursor during the thiobarbituric acid assay. Relative plating efficiency was measured in medial cells and fibroblasts. Alpha-Tocopherolquinone and alpha-tocopherol enhanced the extent of cell proliferation. Alpha-Tocopherolquinone overcame the inhibitory effect of a polyunsaturated fatty acid on the extent of cell proliferation. Menadione was cytotoxic. Thus antioxidant data support the hypothesis that the extent of cell proliferation is controlled in part by lipid peroxidation.
Insights
Polyunsaturated fatty acids increase malondialdehyde (MDA) in cells, indicating lipid peroxidation. Antioxidants like alpha-tocopherol inhibit this process, suggesting lipid peroxidation controls cell proliferation.
Area of Science:
- Biochemistry
- Cell Biology
- Oxidative Stress
Background:
- Lipid peroxidation, measured by malondialdehyde (MDA) formation, is a key indicator of oxidative damage.
- Polyunsaturated fatty acids (PUFAs) are susceptible to peroxidation and can influence cellular processes.
Purpose of the Study:
- To investigate the generation of MDA from specific PUFAs in cultured aortic medial cells and fibroblasts.
- To examine the effects of antioxidants and other compounds on MDA formation and cell proliferation.
Main Methods:
- Measurement of MDA using the thio-barbituric acid assay.
- Incubation of guinea pig aortic medial cells and fibroblasts with PUFAs.
- Treatment with indomethacin, alpha-tocopherol, alpha-tocopherolquinone, BHT, and menadione.
- Assessment of relative plating efficiency to determine cell proliferation.
Main Results:
- Specific PUFAs (8,11,14-eicosatrienoic acid, 5,8,11,14-eicosatetraenoic acid, 7,10,13,16-docosatetraenoic acid) significantly increased MDA formation in a time-dependent manner.
- MDA or its precursor remained intracellular.
- Indomethacin enhanced MDA formation, while alpha-tocopherol, alpha-tocopherolquinone, and BHT inhibited it.
- Alpha-tocopherol and alpha-tocopherolquinone promoted cell proliferation and counteracted PUFA-induced inhibition, whereas menadione was cytotoxic.
Conclusions:
- Lipid peroxidation, indicated by intracellular MDA generation from PUFAs, plays a role in controlling cell proliferation.
- Antioxidants like alpha-tocopherol and alpha-tocopherolquinone can modulate lipid peroxidation and positively influence cell proliferation.