Matrine Effectively Modulates the MMP9/NF-κB Signaling Pathway and Inhibits Macrophage Polarization in Peri-Implantitis

Objective: The macrophage polarization is predominantly involved in the progression of peri-implantitis. However, the matrine has been shown to potentially inhibit M1 macrophage polarization. Therefore, this study aimed to explore the in vivo effects of matrine on M1 macrophage polarization in peri-implantitis.Methods: RAW264.7 cells were treated with lipopolysaccharide (LPS) and then incubated with different concentrations (0, 20, 50 mu M) of matrine. The cells were transfected with si-matrix metallopeptidase 9 (si-MMP9) and si-nuclear factor-kappa B (si-NF-kappa B). Furthermore, Sprague-Dawley (SD) rats were used to establish peri-implantitis models by surgically implanting titanium alloy screws into the left upper first molar. The rats were divided into four groups, each containing five rates: a control group, a model group, a saline group, and a matrine group. The rats in the matrine group were administered matrine (100 mg/kg) every day for four weeks. However, in the saline group, the rats were injected with an equivalent dose of physiological saline. After this treatment, the rats were anesthetized with 4% to 5% isoflurane, and their maxillae were dissected. The levels of matrix metallopeptidase 9 (MMP9) and nuclear factor-kappa B (NF-kappa B), both at the mRNA and protein levels, were determined in cell lines as well as in rat models using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting methods. Furthermore, the level of inflammatory factors was also evaluated. The cellular viability and apoptosis were analyzed using cell counting kit-8 (CCK-8) assay and flow cytometry. Additionally, macrophage polarization was observed by immunofluorescence, and the inflammatory factor infiltration was assessed using histopathological examination.Results: It was observed that LPS successfully induced M1 macrophages (p < 0.001), while matrine significantly reduced the activity of M1 macrophages (p < 0.001). Moreover, matrine also induced apoptosis (p < 0.001) and promoted the polarization of M2 macrophages (p < 0.001), thereby inhibiting the expression of inflammatory factors tumor necrosis factor (TNF)-alpha (p < 0.001), interleukin (IL)-1 beta (p < 0.001), IL-6 (p < 0.001), and increasing the levels of IL-10 (p < 0.001) and transforming growth factor (TGF)-beta (p < 0.001) by decreasing the levels of MMP9 (p < 0.01) and NF-kappa B (p < 0.01). Additionally, the rat model of peri-implantitis was successfully constructed. Matrine treatment significantly inhibited inflammatory infiltration (p < 0.01) and successfully inhibited the polarization of M1 macrophages (p < 0.001) by regulating the MMP9/NF-kappa B signaling pathway.Conclusion: Matrine effectively decreases the inflammatory infiltration in peri-implantitis by regulating the MMP9/NF-kappa B sig-naling pathway, inhibiting M1 macrophage polarization and inducing M2 phenotype.