Histopathological and biomechanical effects of papaverine application in rotator cuff tendinopathy treatment: An experimental rat model study.

OBJECTIVE: This study aimed to evaluate the histopathological and biomechanical effects of intraperitoneal (systemic) and locally applied Papaverine on tendon healing in a rat rotator cuff model in which collagenase - induced tendinopathy was induced. METHODS: Twenty-four adult male Sprague-Dawley rats were randomly allocated into three groups: Group 1 (control), Group 2 (local papav erine application), and Group 3 (intraperitoneal papaverine application). Supraspinatus tendinopathy was induced by surgical injection of Type I collagenase. Group 2 received local papaverine at the surgical site, while Group 3 received systemic intraperitoneal papaverine. On day 30, the rats were sacrificed, and shoulder tissues were harvested for histopathological and biomechanical analysis. RESULTS: Histopathological evaluation revealed no significant differences among the groups regarding fiber structure, cellularity, or vascularity (P > .05). In contrast, biomechanical analysis demonstrated that the local papaverine group showed statistically significant superiority over the other groups in tendon breaking force, elongation, and durability (P < .0001). CONCLUSION: Local application of papaverine improved the biomechanical durability of tendon tissue, although no significant histopatho logical differences were observed. These findings suggest that papaverine may contribute to regenerative processes and could serve as a supportive agent in the treatment of rotator cuff tendinopathy. However, further studies are required to confirm its clinical applicability.   Cite this article as: Çelebi ME, Meydaneri S, Çakmak O. Histopathological and biomechanical effects of papaverine application in rotator cuff tendinopathy treatment: An experimental rat model study. Acta Orthop Traumatol Turc., 2025;59(6):428-433.