Matrine attenuates heterotopic ossification by suppressing TGF-β induced mesenchymal stromal cell migration and osteogenic differentiation

Heterotopic ossification (HO) is a debilitating disease characterized by extraskeletal bone formation. Active TGF-β recruits mesenchymal stromal cells (MSCs), which contribute to trauma-induced HO. Inhibiting TGF-β induced MSC migration and osteogenic differentiation could be a promising treatment for HO. Matrine is an alkaloid from the genus Sophora that can suppress pancreatic and hepatic fibrosis by regulating TGF-β/Smad signaling. We conducted this study to evaluate the effects of matrine on HO and explore the mechanisms, we carried out this study. Achilles tendon puncture was performed in C57BL/6J male mice to establish the HO model. Following treatment with matrine for 3, 6, 9, and 15 weeks, mice were sacrificed and tendons were collected. In vivo, micro-CT, hematoxylin and eosin staining, CD73 and CD90 immunofluorescence, and osteocalcin staining were used to evaluate the development of HO. In vitro, a transwell migration assay was used to evaluate MSC migration. Immunohistochemistry, immunofluorescence and western blotting were used to evaluate the TGF-β/Smad2/3 pathway. Real-time PCR was conducted to analyze the transcription of alkaline phosphatase (Alp), runt-related transcription factor-2 (Runx2), osteocalcin (Ocn), osteopontin (Opn), and type I collagen (Col1). ALP activity and alizarin red staining were used to assess MSC osteogenic differentiation. In vivo, matrine significantly reduced ossification and inhibited HO progression. In vitro, matrine significantly suppressed MSC migration, ALP activity, and mineralization of MSCs. Mechanistically, matrine inhibited TGF-β induced Smad2/3 phosphorylation and transcription of Runx2, Alp, and Ocn after osteoinduction. Matrine inhibited HO by suppressing the migration and osteogenic differentiation of TGF-β-induced-MSCsin mice.