Tetrandrine inhibits the occurrence and development of frozen shoulder by inhibiting inflammation, angiogenesis, and fibrosis

Frozen shoulders (FS) is a major clinical concern, where chronic synovial inflammation, abnormal angiogenesis, and fibrosis represent the critical pathologies in the glenohumeral capsule. However, no pharmacotherapy has been introduced to treat this pathology. Tetrandrine (TET) has been proposed as a treatment for many diseases due to its strong anti-inflammatory, anti-angiogenic, and anti-fibrotic effects. To study the anti-inflammatory, anti-angiogenic, and anti-fibrotic effects of TET on FS, and identify whether TET can prevent the development of FS in rats. A controlled laboratory study. Forty-eight male Sprague-Dawley (SD) rats were randomly divided into control, TET, and FS groups. The TET group was intraperitoneally injected with TET every 2 days. TET and saline treatment were started on the day of FS surgery. After 8 weeks, the animals were sacrificed, and samples were collected for X-ray examination, glenohumeral range of motion (ROM) evaluation, histology and immunohistochemistry analysis, transmission electron microscopy (TEM) observation, and profibrogenic factors as well as proinflammatory cytokines measurements. No significant difference in shoulder ROM was observed between the TET and control groups, but a significant difference was noted between these groups and the FS group (P