Force-Induced Nitric Oxide Promotes Osteogenic Activity during Orthodontic Tooth Movement in Mice

Figure 4

Cyclic tensile force induces NO production and NOS expression to regulate osteogenesis of hPDLSCs. (a) The concentration of NO₂^- secreted by hPDLSCs in the supernatant after CTF application. The concentration of NO₂^- increased significantly after 12 h and 24 h, ; (b, c) NOS expression in hPDLSCs was upregulated as assessed by western blotting (b) and RT-PCR. (c) and . Bars and error bars show mean and standard error. (d) RUNX2, Osterix, and osteopontin mRNA levels were increased in hPDLSCs after loading, measured by qPCR. (e) The western blot of RUNX2 shows the same tendency. (f) To study the effect of different concentrations of NO, we use NOS inhibitor L-NMMA and NO donor sodium nitroprusside (SNP) during cyclic tensile force application. The concentrations of NO₂^- in cell culture supernatant were examined by the Griess Method. Suppressing NOS by L-NMMA inhibited the increase of NO in human PDLSCs after CTF application. SNP increased NO level in the cell culture supernatant. (g) The results of qPCR showed that RUNX2, Osterix, osteopontin, and mRNA expression was decreased when NO production was suppressed during CTF, and they were increased when NO production was promoted during CTF. (h) The western blot of RUNX2 shows the same tendency. , , and . Bars and error bars show mean and standard error.

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