TY - JOUR
T1 - Molecular mechanism of nitric oxide-induced osteoblast apoptosis
AU - Chen, Ruei-Ming
AU - Chen, Ta-Liang
AU - Chiu, Wen-Ta
AU - Chang, Chia Chen
N1 - Funding Information:
This study was supported by grants NSC91-2314-B-038-031 and NSC92-2314-B-038-010 from the National Science Council, Taipei, Taiwan, ROC.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005/3
Y1 - 2005/3
N2 - Nitric oxide (NO) can regulate osteoblast activities. Our previous study showed that NO induced osteoblast apoptosis [Chen RM, Liu HC, Lin YL, Jean WC, Chen JS, Wang JH. Nitric oxide induces osteoblast apoptosis through the de novo synthesis of Bax protein. J Orthop Res 2002;20:295-302]. This study was further aimed to evaluate the mechanism of NO-induced osteoblast apoptosis from the viewpoints of mitochondrial functions, intracellular oxidative stress, and the anti-apoptotic Bcl-2 protein using neonatal rat calvarial osteoblasts as the experimental model. Exposure of osteoblasts to sodium nitroprusside (SNP), an NO donor, significantly increased amounts of lactate dehydrogenase in the culture medium, and decreased cell viability in concentration- and time-dependent manners. Administration of SNP in osteoblasts time-dependently led to DNA fragmentation. The mitochondrial membrane potential was significantly reduced following SNP administration. SNP decreased complex I NADH dehydrogenase activity in a time-dependent manner. Levels of cellular adenosine triphosphate (ATP) were suppressed by SNP. In parallel with the mitochondrial dysfunction, SNP time-dependently increased levels of intracellular reactive oxygen species. Immunoblotting analysis revealed that SNP reduced Bcl-2 protein levels. Exposure to lipopolysaccharide (LPS) and IFN-γ significant increased endogenous nitrite production. In parallel with the increase in endogenous NO, administration of LPS and IFN-γ suppressed cell viability, mitochondrial membrane potential, and ATP synthesis. Results of this study show that NO released from SNP can induce osteoblast insults and apoptosis, and the mechanism may involve the modulation of mitochondrial functions, intracellular reactive oxygen species, and Bcl-2 protein.
AB - Nitric oxide (NO) can regulate osteoblast activities. Our previous study showed that NO induced osteoblast apoptosis [Chen RM, Liu HC, Lin YL, Jean WC, Chen JS, Wang JH. Nitric oxide induces osteoblast apoptosis through the de novo synthesis of Bax protein. J Orthop Res 2002;20:295-302]. This study was further aimed to evaluate the mechanism of NO-induced osteoblast apoptosis from the viewpoints of mitochondrial functions, intracellular oxidative stress, and the anti-apoptotic Bcl-2 protein using neonatal rat calvarial osteoblasts as the experimental model. Exposure of osteoblasts to sodium nitroprusside (SNP), an NO donor, significantly increased amounts of lactate dehydrogenase in the culture medium, and decreased cell viability in concentration- and time-dependent manners. Administration of SNP in osteoblasts time-dependently led to DNA fragmentation. The mitochondrial membrane potential was significantly reduced following SNP administration. SNP decreased complex I NADH dehydrogenase activity in a time-dependent manner. Levels of cellular adenosine triphosphate (ATP) were suppressed by SNP. In parallel with the mitochondrial dysfunction, SNP time-dependently increased levels of intracellular reactive oxygen species. Immunoblotting analysis revealed that SNP reduced Bcl-2 protein levels. Exposure to lipopolysaccharide (LPS) and IFN-γ significant increased endogenous nitrite production. In parallel with the increase in endogenous NO, administration of LPS and IFN-γ suppressed cell viability, mitochondrial membrane potential, and ATP synthesis. Results of this study show that NO released from SNP can induce osteoblast insults and apoptosis, and the mechanism may involve the modulation of mitochondrial functions, intracellular reactive oxygen species, and Bcl-2 protein.
KW - Apoptosis
KW - Bcl-2 protein
KW - Mitochondrial functions
KW - Nitric oxide
KW - Osteoblasts
KW - Reactive oxygen species
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U2 - 10.1016/j.orthres.2004.08.011
DO - 10.1016/j.orthres.2004.08.011
M3 - Article
C2 - 15734263
AN - SCOPUS:14244250783
SN - 0736-0266
VL - 23
SP - 462
EP - 468
JO - Journal of Orthopaedic Research
JF - Journal of Orthopaedic Research
IS - 2
ER -