Platelet-rich plasma stimulates cell proliferation and enhances matrix gene expression and synthesis in tenocytes from human rotator cuff tendons with degenerative tears.

BACKGROUND Platelet-rich plasma (PRP) contains various growth factors and appears to have a potential to promote tendon healing, but evidence is lacking regarding its effect on human tenocytes from rotator cuff tendons with degenerative tears. HYPOTHESIS Platelet-rich plasma stimulates cell proliferation and enhances matrix gene expression and synthesis in tenocytes isolated from human rotator cuff tendons with degenerative tears. STUDY DESIGN Controlled laboratory study. METHODS Tenocytes were enzymatically isolated and cultured. To evaluate cell proliferation, tenocytes were cultured with 10% (vol/vol) platelet-poor plasma (PPP), PRP activated with calcium, and PRP activated with calcium and thrombin at platelet concentrations of 100, 200, 400, 800, 1000, 2000, 4000, 8000, and 16,000 × 10(3)/µL for 14 days. Cell number was measured at days 7 and 14. To investigate matrix gene expression and synthesis, cells were cultured with a PPP or PRP gel (10% vol/vol) at a platelet concentration of 1000 × 10(3)/µL for 14 days. Quantitative real-time reverse transcriptase polymerase chain reaction was performed to determine the expressions of type I and III collagen, decorin, tenascin-C, and scleraxis, and measurements of total collagen and glycosaminoglycan (GAG) synthesis were conducted at days 7 and 14. RESULTS Platelet-rich plasma significantly increased cell proliferation at days 7 and 14 in a dose-dependent manner, and the addition of thrombin moved up the plateau of proliferation. Platelet-rich plasma significantly induced the gene expression of type I collagen at day 7 but not at day 14, while it significantly promoted that of type III both at days 7 and 14. The ratio of type III/I collagens did not change at days 7 and 14. The expressions of decorin and scleraxis significantly increased at day 14, whereas that of tenascin-C significantly increased at days 7 and 14. Platelet-rich plasma significantly increased total collagen synthesis at days 7 and 14 and GAG synthesis at day 14. CONCLUSION Platelet-rich plasma promoted cell proliferation and enhanced gene expression and the synthesis of tendon matrix in tenocytes from human rotator cuff tendons with degenerative tears. CLINICAL RELEVANCE These findings suggest that PRP might be used as a useful biological tool for regenerative healing of rotator cuff tears by enhancing the proliferation and matrix synthesis of tenocytes from tendons with degenerative tears.