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Vitamin E inhibits PGE2 and O2- production in rat peritoneal macrophages
1Department of Biochemistry, School of Dentistry, Hokkaido University, Sapporo, Japan.
Abstract:
In order to examine the possible role of vitamin E on the modulation of macrophages, we investigated the effect of vitamin E on O2- and PGE2 production in macrophages. The production of both PGE2 and O2- in rat peritoneal macrophages was dose-dependently stimulated by the addition of PMA and calcium ionophore A23187. However, the macrophages obtained after intraperitoneal injection of vitamin E for six successive days showed less PGE2 and O2- production when stimulated with PMA or A23187 as compared to those of control macrophages. O2- production in control macrophages stimulated with 139 nM PMA and 1 microM A23187 as 4.2 +/- 0.3 and 3.0 +/- 0.2 nmol/min per 10(6) cells, respectively. On the other hand, O2- production by the macrophages from vitamin E-treated rats was 1.5 +/- 0.4 nmol/min per 10(6) cells when stimulated with the PMA, and was not detectable when stimulated with A23187. As for the production of PGE2, control macrophages produced 2.59 +/- 0.70 ng/30 min per 10(6) cells when stimulated with PMA and 8.96 +/- 3.26 ng/30 min per 10(6) cells with the A23187, whereas PGE2 production by the macrophages from vitamin E-treated rats was reduced to 12-20% of the control. By analyzing alpha-tocopherol content and intracellular concentration of calcium ion [( Ca2+]i) in the macrophages isolated from control and vitamin E-treated rats, vitamin E treatment augmented alpha-tocopherol content (384.7 +/- 76.1 vs. 1.2 +/- 0.4 ng/10(6) cells) and decreased free [Ca2+]i when stimulated with A23187 (652 +/- 14 vs. 1201 +/- 223 nM).
Insights
Vitamin E supplementation reduces inflammatory responses in rat macrophages by decreasing superoxide (O2-) and prostaglandin E2 (PGE2) production. This effect is linked to increased alpha-tocopherol and reduced intracellular calcium levels.
Area of Science:
- Immunology
- Nutritional Science
- Cell Biology
Background:
- Macrophages play a crucial role in immune responses.
- Prostaglandin E2 (PGE2) and superoxide (O2-) are key inflammatory mediators produced by macrophages.
- Vitamin E is an antioxidant with potential immunomodulatory effects.
Purpose of the Study:
- To investigate the effect of vitamin E on O2- and PGE2 production in rat peritoneal macrophages.
- To elucidate the role of vitamin E in modulating macrophage inflammatory activity.
Main Methods:
- Rats were treated intraperitoneally with vitamin E for six consecutive days.
- Macrophages were isolated and stimulated with phorbol 12-myristate 13-acetate (PMA) or calcium ionophore A23187.
- O2- and PGE2 production levels were measured.
- Alpha-tocopherol content and intracellular calcium ion concentration ([Ca2+]i) were analyzed.
Main Results:
- Vitamin E treatment significantly reduced O2- production stimulated by PMA and A23187.
- PGE2 production was decreased to 12-20% of control levels in vitamin E-treated macrophages.
- Vitamin E supplementation increased macrophage alpha-tocopherol content.
- Intracellular calcium ion concentration ([Ca2+]i) was decreased in vitamin E-treated macrophages upon stimulation with A23187.
Conclusions:
- Vitamin E modulates macrophage inflammatory responses by suppressing O2- and PGE2 production.
- The observed effects may be mediated by increased intracellular alpha-tocopherol and reduced intracellular calcium levels.
- Vitamin E demonstrates potential as an immunomodulatory agent in inflammatory conditions.