An analysis of the cytokine profile of platelet-rich plasma when combined in vitro with low versus high molecular weight hyaluronic acid

Aims: Platelet-rich plasma (PRP) and hyaluronic acid (HA) are nonoperative treatments for osteoarthritis (OA) of large joints. Clinically, some endorse the use of both methods together for a theoretical synergistic effect therapeutically, with limited evidence. This study aimed to evaluate whether the molecular weight of HA influences the cytokines released from PRP in vitro. Methods: Leucocyte-rich PRP was prepared from venous blood of ten healthy males (aged 18 to 35 years). Three groups were tested: PRP + phosphate-buffered saline (PBS, control), PRP + low molecular weight HA (LMWHA, and PRP + high molecular weight HA (HMWHA). Samples were incubated at 37°C, and the concentrations of insulin-like growth factor binding protein 1 (IGFBP1), interleukin-1β (IL-1β), interleukin-1 receptor antagonist (IL-1RA), IL-6, IL-10, platelet-derived growth factor subunit B (PDGF-BB), transforming growth factor-β (TGF-β1), and tumour necrosis factor-alpha (TNF-α) were measured at two hours (Day 0) and 72 hours (Day 3). Data were analyzed using repeated measures analysis of variance (p < 0.05). A Bonferroni test was performed as a post hoc analysis. Results: PDGF-BB decreased significantly (p < 0.001) from Day 0 to 3 across all groups. This was more pronounced in the presence of HA, regardless of molecular weight. IL-1β rose significantly in HA-treated groups only (p = 0.009). No significant intergroup differences emerged for IGFBP1, IL-6, TGF-β1, or TNF-α at either timepoint. There was a significant increase in both IL-1RA (p = 0.016), and IL-10 (p < 0.001) concentration from Day 0 to 3. There were no significant differences in IL-1RA or IL-10 between the control, LMWHA, and HMWHA groups at Day 0 or 3. Conclusion: The molecular weight of HA did not improve the cytokine profile of PRP in vitro, suggesting that both LMWHA and HMWHA formulations may be comparable when used in combination with PRP, at least in males.