Long-term cytokine and growth factor release from equine platelet-rich fibrin clots obtained with two different centrifugation protocols.

Objectives: To compare the temporal release (over three weeks) of tumor necrosis factor alpha (TNF-α), interleukin 4 (IL-4), IL-1 receptor antagonist (IL-1ra), platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta-1 (TGF-β) from two platelet-rich fibrin (PRF) preparations from equine blood obtained at either 240g/8min or 416g/10min.

Methods: Whole blood from 10 horses was used to obtain PRF clots by two different centrifugation protocols. After 1h of rest, PRF clots were deposited in wells with culture medium, which was changed at 6h, 24h and then every 48h to 21days. Cytokines and GFs were measured by ELISA at 1h (serum supernatants from PRF clots) and all time points of culture medium change. A negative control (plasma) and a positive control (blood lysate) were also included.

Results: There were no relevant differences between the two protocols for the temporal release of proteins. However, a significant (p=0.01) effect of time was noted. All cytokines were detected after 6h of PRF clot culture until day 21. GF were detected at 1h until day 21. The concentrations for these proteins diminished gradually over time. A highly significant (p=0.01) correlation was noticed between all the proteins evaluated.

Conclusions: Leukocytes enmeshed in PRF clots were able to produce cytokines, TGF-β and PDGF-BB. These findings demonstrate a paramount role of leukocytes in wound healing induced or modified by PRF clots in mammals.