Effects of Nitric Oxide on Bone Metabolism

Korean J Bone Metab > Volume 8(1); 2001 > Article

Original Article

Korean Journal of Bone Metabolism 2001;8(1):9-16.

Effects of Nitric Oxide on Bone Metabolism

산화질소가 골 대사에 미치는 영향

박용구,류병규

경희대학교 의과대학 병리학교실

Abstract

Background
Nitric oxide (NO) is the product of deamination of the endogenous substrate LArginine by nitric oxide synthase (NOS). The inducible NOS isoform is activated by lipopolysaccharides and other cytokines. NO has been implicated in bone remodeling and regulates osteoclasts activity. It was hypothesized that NOS mediates bone remodeling.
Methods
We used iNOS knock-out mouse and to study the effects of two NO donors, sodium nitroprusside (SNP) and sodium-nitro-acetylpenicillamine (SNAP), and two NOS inhibitors; L-NG-nitroL-arginine methyl ester (L-NAME), which is a general inhibitor of NOS activity; and aminoguanidine (AG), a selective inhibitor of the inducible NOS isoform. Bone labeling agents were injected twice. Serum alkaline phosphatase (ALP), calcium, phosphorus and tartrate resistant acid phosphatase (TRAP) were measured. Bone volume, mineral apposition rate were measured at the proximal tibia using the standard bone histomorphometry.
Results
ALP was slightly elevated in the groups treated with SNAP and SNP. TRAP activity was slighly decreased in the groups treated with SNP and SNAP, however in the group treated with AG, it was elevated than control iNOS knock-out mouse. Bone volume was slightly decreased in the experimental groups than control. Osteoid thickness was increased in the group treated with AG. Mineral apposition rate was increased in the group treated with SNP. However, all of these parameters were not statistically significant.
Conclusion
In this study, we conclude that NO can effect slightly bone remodeling in the iNOS knock-out mouse through other than iNOS pathway. However more precise molecular and control study are needed for further work.

Key Words: iNOS, Knock-out mouse, Bone histomorphometry