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Autoregulation of Quartz-induced iNOS by iNOS-derived Hydrogen Peroxide in Rat2 Fibroblast
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Kyoung Ah Kim, Hae Yun Nam, Je Hyeok Mun, Jin Sook Jeong, Young Lim, Chee Kyung Chung
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Korean Journal of Occupational and Environmental Medicine 2001;13(4):385-392. Published online December 31, 2001
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DOI: https://doi.org/10.35371/kjoem.2001.13.4.385
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 Abstract
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- OBJECTIVES
This study was performed in order to investigate the molecular mechanism regulating nitric oxide synthase(NOS) induced by alpha-quartz in Rat2 fibroblast.
METHODS
alpha-quartz-induced nitric oxide(NO) and H2O2 formation and alpha- quartz-induced iNOS protein expression in Rat2 fibroblast were monitored. With iNOS inhibitor(L-N6- (1-iminoethyl)lysine hydrochloride, L-NIL) or antioxidant(catalase), we observed NO and H2O2 formation and iNOS protein expression in Rat2 fibroblast stimulated with alpha-quartz.
RESULTS
alpha-quartz stimulated iNOS-induced NO and H2O2 formation in Rat2 fibroblast. L-NIL inhibited H2O2 formation and iNOS protein expression by alpha-quartz in Rat2 fibroblast. Pretreatment with catalase blocked the autoinhibitory pathway of iNOS by iNOSinduced H2O2, therefore H2O2 and NO production and iNOS protein expression were increased in Rat2 fibrobalst stimulated with alpha-quartz CONCLUSIONS: alpha-quartz-induced iNOS stimulated H2O2 formation in Rat2 fibroblast. INOS-induced H2O2 by alpha-quartz plays an important role in the autoinhibition pathway for regulating the iNOS function in Rat2 fibroblast
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Autoproliferation of Fibroblast by Exposure to Crystalline Silica - Evaluation by H2O2 and PDGF-AA and TGF beta
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Byoung Young Ahn, Kyoung Ah Kim, Je Hyeok Mun, Jin Sook Jeong, Eun Kyung Kim, Young Lim
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Korean Journal of Occupational and Environmental Medicine 2000;12(2):209-217. Published online June 30, 2000
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DOI: https://doi.org/10.35371/kjoem.2000.12.2.209
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Abstract
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- OBJECTIVES
The aim of this study is to find out the activity of autoproliferation of ratfibroblast exposed to crystalline silica and the role of mediators secreted from rat fibroblast.
METHODS
The effect of alpha-quartz on production of growth factor (platelet-derived growth factor-AA and transforming growth factor beta)from rat fibroblasts were evaluated by ELISA and immunocytochemical analysis.
Gene expression of these growth factors in rat fibrobast exposed to crystalline silica was evaluated by RT-PCR.
Furthermore, fibroblast proliferation by culture supernatant of rat fibroblast was assayed by the neutral red test.
RESULTS
The amounts of H2O2 and growth factors synthesized in rat fibroblasts were significantly increased by the stimulation of crystalline silica(alpha-quartz), which showed the dose-dependent manner to the concentration of alpha-quartz with the maximum response at the dosage of 100 microgram/cm2. The result of RT-PCR demonstrated that alpha-quartz induced gene expression of PDGF-AA and TGFbeta in rat fibroblast. We also found that supernatant of alpha-quartz-cocultured rat fibroblast induced a significant proliferation of fibroblast.
CONCLUSION
Crystalline silica directly induce functional change in fibroblast such as increased release of reactive oxygen species and growth factors. The products of these functional change promote fibroblast proliferation via autocrine loop.
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