Fig. 1: BMDM-derived osteoclastogenesis increased in the development of rat AP.

a Flow diagram of the construction of apical periodontitis (AP) in rats (n = 9 rats per group). b The representative micro-CT images of alveolar bone (AB) tissues in the rats with AP (n = 3 independent experiments; mean ± SD). The bone resorption fraction was defined as bone resorption surface area (BRS)/bone resorption volume (BRV). c Morphometric imaging showed TRAP staining in the AB tissues of rats with AP. Scale bar indicates 1 mm in the left and scale bar indicates 100 μm in the right. Arrowheads pointed the TRAP-positive surfaces (n = 3 independent experiments). d TRAP-positive multinucleated cells were counted as osteoclast (OC) (n = 3 independent experiments with 3 technical replicates; mean ± SD). e The mRNA levels of nuclear factor of activated T cells (NFATc1), matrix metalloprotein 9 (MMP9), and cathepsin K (CTSK) in the AB tissues of rats were determined (n = 3 independent experiments; mean ± SD). f The protein expression in the AB tissues of rats were determined (n = 3 independent experiments; mean ± SD). g Flow diagram of the induction of osteoclast in vitro (n = 3 mice per group). h Representative pictures of TRAP-stained OC. Scale bar indicates 100 μm (n = 3 independent experiments). i The relative mRNA levels in the process of osteoclastogenesis were determined (n = 3 independent experiments; mean ± SD). j The protein expression in the process of osteoclastogenesis (n = 3 independent experiments). k The expression of protein in the process of osteoclastogenesis were determined (n = 3 independent experiments; mean ± SD). For the AP rat model, the contralateral teeth served as control.The major statistical procedures applied were: Shapro–Wiik test (b, d, e, f, i, j, k), F-test (b, d, k), Repeated measures ANOVA (b, d), Kruskal–Wallis H test and Dunnett-t test (e, f, i, j, k). The statistical test used was two-sided. c (f). Source data are available online for this figure.