[abstract] HYPERBARIC OXYGEN REDUCES MACROPHAGE PROLIFERATION IN VITRO

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[abstract] HYPERBARIC OXYGEN REDUCES MACROPHAGE PROLIFERATION IN VITRO

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Title: [abstract] HYPERBARIC OXYGEN REDUCES MACROPHAGE PROLIFERATION IN VITRO
Author: Kalns, JE; Krock, LP; Piepmeier, EH
Abstract: BACKGROUND: Free radicals are mediators of tissue injury inflicted by macrophages during inflammation. Since the production of free radicals including nitric oxide and peroxynitrite is dependent on availability of oxygen, we hypothesized that HBO may restore the ability of hypoxic macrophages to produce free radicals. This hypothesis was tested in vitro using a macrophage cell line and cytokines to simulate the molecular cues present during inflammation. METHODS: The macrophage-like murine cell line RAW 264.7 was maintained under normoxic (21percent O2, 5percent CO2, balance N2) or hypoxic 1percent O2, 5percent CO2, balance N2) conditions for two days then activated with 5ug/ml lipopolysaccharide plus 100U/ml interferon-y. After 24 or 48h, cell numbers, nitrite concentration and cellular accumulation of 3-nitrotyrosine (3-NT), an indicator of peroxynitrite exposure, were determined. RESULTS: Activated hypoxic cells accumulated 67percent and 95percent less NO2 and 3-NT respectively, than normoxic cells. HBO (1.5h, 3.0 ATA 100percent O2) reduced hypoxic and normoxic cell numbers at 48h by 20percent but had no effect on activated cells. Hypoxic cells returned to normoxic conditions after activation accumulated 12percent less 3-NT and 35percent less NO2 at 48h than cells maintained constantly under normoxic conditions, suggesting that macrophages rapidly recover the ability to make free radicals when normoxic conditions are restored. HBO had no effect on cell number, NO2 or 3-NT accumulation in activated hypoxic or normoxic cells. CONCLUSIONS: HBO reduces macrophage proliferation when inflammatory molecular cues are absent. Hypoxic macrophages returned to normoxic conditions recover the ability to produce free radicals within 24h. Clinically relevant HBO exposure does not restore the ability of hypoxic macrophages to produce free radicals.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: http://archive.rubicon-foundation.org/698
Date: 1998

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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