Introduction: Matrix metalloproteinases (MMPs) are involved in physiological events such as restructuring of the tissue, morphogenesis, wound healing and normal developmental process. Use of diclofenac sodium following rotator cuff repair can disrupt healing of tendon through acting on MMPs.
Materials and methods: Supraspinatus tendons of rats (n = 84) were detached from their insertion on humerus, and repaired to anatomic footprint. Rats were divided into study group (n = 42) and control group (n = 42). Study group received a dose of 1 mg/kg daily diclofenac sodium subcutaneously. The rats were killed at weeks 1, 3 and 6, and seven rats from each groups were included in biomechanical and immunohistological examinations. Immunohistological staining of MMP-2, MMP-3 and MMP13 were used.
Results: Maximum load was reduced in the study group at the end of week 1 (8.76 vs. 5.28 N) (p = 0.01). MMP-3 level was statistically significantly lower in the study group at the end of week 1. MMP-13 level and stiffness decreased towards week 6 in the study group while in the control group the level of MMP-2 decreased towards week 6.
Conclusion: Diclofenac has an impact on the levels of MMP-2, MMP-3 and MMP-13, which are needed for normal healing process, and it can also lead to disruption of tendon healing.