Immunostaining analysis of protein expression of IGF‐1, MMP‐9, and TNF‐α in different sample groups. (A) IGF‐1 showed significantly elevated expression in response to simvastatin treatment(s) compared to experimental periodontitis (ExP and ExP + PPi) and unmanipulated controls. Unmanipulated controls have limited expression of MMP‐9 and TNF‐α, whereas in ExP groups, MMP‐9 and TNF‐α expression was significantly upregulated. However, SIM treatment remarkably reduced the expression of MMP‐9 and TNF‐α. Each bar value, as stated, represents the size and magnification of the image. (B) Quantification of staining intensity of IGF‐1, MMP‐9, and TNF‐α in different sample groups. Statistical analysis was performed by one‐way ANOVA. Error bars represent 95% CI. ExP = experimental periodontitis; SIM‐PPI = simvastatin‐pyrophosphate. *p < 0.05; **p < 0.01; ***p < 0.001.