An In Vitro Investigation Into the Effects of Repetitive Motion and Nonsteroidal Antiinflammatory Medication on Human Tendon Fibroblasts

Abstract

Soft tissue injuries due to repetitive motion are common sports injuries and are often treated with antiinflamma tory therapies. We investigated the in vitro effects of repetitive motion and nonsteroidal antiinflammatory medication on human tendon fibroblasts. In addition, we studied the effects related to the presence of inflam matory cells. Repetitive motion was associated with an increased release of prostaglandin E2 and increased deoxyribonucleic acid (DNA) and protein synthesis. The presence of nonsteroidal antiinflammatory medication decreased prostaglandin E2 release and DNA synthe sis but increased protein synthesis. Contact with mac rophages caused a marked additional increase in pros taglandin E2 and a concomitant increase in DNA synthesis. Release of interleukin-6 by the macrophages also suggested that this cytokine plays a role in the re sponse to repetitive motion. Our results can aid in the search for a more scientific approach to the treatment of soft tissue injuries associated with repetitive motion. They suggest that nonsteroidal antiinflammatory medi cation may have potentially negative effects during the proliferative phase of a healing since it was associated with decreased DNA synthesis. However, it may be beneficial in the maturation and remodeling phase since it stimulated protein synthesis.