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Effects of Infrared Light on Release of NO and SO in Osteoblasts
Author(s) -
Rabe Jacob B,
Struve Janine A,
Weihrauch Dorothee,
Marshall Scott A,
Ninomiya James T
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.647.9
Subject(s) - chemistry , nitric oxide , hypoxia (environmental) , osteoblast , oxygen tension , biophysics , oxygen , microbiology and biotechnology , biochemistry , biology , in vitro , organic chemistry
Hypoxia surrounds bone fractures as a result of interruption of the intact vasculature. Nitric Oxide (NO) and superoxide (SO) are important signaling molecules in bone formation. Our previous studies showed infrared (IR) light increases osteoblast (OB) proliferation. We hypothesize that the application of IR light alters OB mediators after hypoxia (hyp). We tested this by determining the hyp tolerance of OBs. MC3T3‐E1 cells were exposed to different durations of hyp in a 1% oxygen tension chamber (1h, 2h, 4h, 6h, 8h, 10h, 18h). Media was tested for LDH release. OBs were exposed to IR light (830nm, 4J/cm2) following 6h hyp insult. Measurements of NO and SO using DAF‐DA and DHE, respectively, followed. Fluorescence intensity was analyzed using confocal microscopy. Protein expression of HIF1α and VEGF was determined using immunohistochemistry. 4h hyp cells without glucose showed significant differences of LDH release compared to all other groups. Differences peaked at 8 h. NO and SO levels from cells not exposed to NIR light, were increased after hyp as compared to those of control. Intensity levels of cells exposed to IR were increased for both hyp and control conditions, as compared to those not exposed to the light. HIF 1α and VEGF expression were up in hypoxia and reduced after IR exposure. IR light might be clinically relevant in enhancing the rate or extent of fracture healing.