Inflammatory and angiogenic mRNA levels are altered in a supraspinatus tendon overuse animal model.

Shoulder overuse injuries, especially those to the supraspinatus tendon of the rotator cuff, are common musculoskeletal disorders. Unfortunately, little is known about the disease etiology and pathogenesis. The objective of this study was to determine the levels of specific inflammatory and angiogenic markers in a rat supraspinatus tendon overuse injury model. We hypothesized that inflammation would not be present early in the overuse protocol. Conversely, we hypothesized that the overuse protocol would result in increased angiogenesis early. Increases in five-lipoxygenase activating protein, cyclooxygenase-2, vascular endothelial growth factor, and von Willebrand factor were evaluated by use of reverse transcription-polymerase chain reaction from 1 day through 16 weeks of treadmill running (overuse protocol). These results provide important information on the role of angiogenesis and inflammation in the disease process. Future studies will further evaluate the mechanisms of the disease process as well as potential targeted treatment modalities.