[Inflammation and tendon healing]

Tendons are extracellular matrix rich structures allowing the transmission of forces generated by skeletal muscles to bones in order to produce movements. Some intrinsic characteristics of tendons, namely hypovascularity and hypocellularity, may explain their slow rate of healing. A growing body of evidence suggests that the inflammatory process, essential for pathogen clearance and injury scavenging, may play opposite functions in tendon healing. For instance, inflammation can lead to degradation of intact collagen and to viable cell death, thereby increasing the functional deficit and recovery period. Paradoxically, many cellular and subcellular events occurring during the inflammatory response lead to the release of a plethora of growth factors that trigger the healing phase. Prostaglandins are implicated in the inflammatory process and may also contribute to the primary steps of tendon healing. Prolonged administration of non steroidal anti-inflammatory drugs (NSAIDs) is a common practice following musculoskeletal injuries. However, there is no clear consensus on the effect of NSAIDs on tendon healing. This review presents a contemporary vision of the inflammatory process following tendon injury and examines the roles of the constitutive and inducible COX-derived prostaglandins. The effect of COX inhibitors will be addressed and special attention will be taken to describe COX-independent effects of these pharmacological inhibitors. Together, this review is an attempt to guide readers toward a more conscientious use of NSAIDs following tendon injuries.