Berberine regulates bone metabolism in apical periodontitis by remodelling the extracellular matrix

Abstract Objectives The objectives of this study were to explore the role and related mechanism of berberine in repairing bone destruction in apical periodontics (AP). Materials and Methods AP was established in 14 of 21 male Wistar rats (four weeks of age; 70–80 g) for 3 weeks. The canals were cleaned and administered berberine (2 mg/ml; n = 7) or calcium hydroxide (100 mg/ml; control; n = 7), followed by glass ionomer cement sealing. After 3 weeks, specimen collection followed by micro‐computed tomography (μ‐CT) and histological staining was performed, including haematoxylin and eosin staining, Masson's trichrome staining, tartrate‐resistant acid phosphatase staining, immunohistochemistry and immunofluorescence histochemistry. Results μ‐CT showed that AP lesion volume reduced in the berberine group. Histopathology showed that berberine decreased the activity and number of osteoclasts but increased the expression of proteins related to osteoblast differentiation, including alkaline phosphatase and osterix. The immune cell, T cell, dendritic cell and macrophage counts were significantly decreased in the berberine group. In the berberine group, the expression of extracellular matrix‐degraded proteases, metalloproteinases, was decreased; however, that of extracellular matrix‐stable proteases, lysyl oxidases, was increased. Conclusions Berberine controlled the inflammatory response and regulated bone metabolism in AP by reducing metalloproteinase expression and increasing lysyl oxidases expression.