Leukocyte-Rich Platelet-Rich Plasma Has Better Stimulating Effects on Tenocyte Proliferation Compared With Leukocyte-Poor Platelet-Rich Plasma

Background: Rotator cuff (RC) tendinopathy is one of the most common causes of shoulder pain. Platelet-rich plasma (PRP) has been frequently used in clinical scenarios, but its efficacy remains inconsistent. Purpose: To investigate the different responses of human tenocytes from torn RCs to leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) in a 2-chamber coculture device. Study Design: Controlled laboratory study. Methods: PRP was prepared using different platelet and leukocyte concentrations according to 5 groups: (1) LR-PRP with 5000 platelets/mu L, (2) LR-PRP with 10,000 platelets/mu L, (3) LP-PRP with 5000 platelets/mu L, (4) LP-PRP with 10,000 platelets/mu L, and (5) control with only culture medium supplementation and without PRP stimulation. Platelet-derived growth factor-AB (PDGF-AB) and transforming growth factor-beta 1 (TGF-beta 1) were measured in LR-PRP and LP-PRP via enzyme-linked immunosorbent assay. Microscopy, water-soluble tetrazolium salt assay, and quantitative real-time polymerase chain reaction were used to investigate the morphology, proliferation, and gene expression of RC tenocytes exposed to different PRP formulations. Data were collected from at least 3 independent measurements. The results were analyzed via 1-way analysis of variance, followed by the post hoc Bonferroni test. Results: The ratio of leukocytes to 5000 platelets/mu L was 29.5 times higher in LR-PRP than in LP-PRP (P < .05). In the 5000 platelets/mu L groups, the levels of TGF-beta 1 and PDGF-AB were both significantly higher in LR-PRP versus LP-PRP (TGF-beta 1: 367.0 +/- 16.5 vs 308.6 +/- 30.3 pg/mL, respectively [P = .043]; PDGF-AB: 172.1 +/- 1.8 vs 94.1 +/- 4.2 pg/mL, respectively [P < .001]). Compared with the control group, RC tenocyte proliferation was 1.42 +/- 0.01 and 1.41 +/- 0.03 times higher in the LR-PRP groups with 5000 platelets/mu L and 10,000 platelets/mu L, respectively (P < .05). The expression of tenocyte-related genes was higher in tenocytes cultured in LR-PRP. Conclusion: Both the LR-PRP groups with 5000 platelets/mu L and 10,000 platelets/mu L induced more growth factor release and increased RC tenocyte proliferation than did the LP-PRP groups.