Ultrastructure and growth factor content of equine platelet-rich fibrin gels

To compare fiber diameter, pore area, compressive stiffness, gelation properties, and selected growth factor content of platelet-rich fibrin gels (PRFGs) and conventional fibrin gels (FGs).

PRFGs and conventional FGs prepared from the blood of 10 healthy horses.

Autologous fibrinogen was used to form conventional FGs. The PRFGs were formed from autologous platelet-rich plasma of various platelet concentrations (100 × 10³ platelets/μL, 250 × 10³ platelets/μL, 500 × 10³ platelets/μL, and 1,000 × 10³ platelets/μL). All gels contained an identical fibrinogen concentration (20 mg/mL). Fiber diameter and pore area were evaluated with scanning electron microscopy. Maximum gelation rate was assessed with spectrophotometry, and gel stiffness was determined by measuring the compressive modulus. Gel weights were measured serially over 14 days as an index of contraction (volume loss). Platelet-derived growth factor-BB and transforming growth factor-β1 concentrations were quantified with ELISAs.

Fiber diameters were significantly larger and mean pore areas were significantly smaller in PRFGs than in conventional FGs. Gel weight decreased significantly over time, differed significantly between PRFGs and conventional FGs, and was significantly correlated with platelet concentration. Platelet-derived growth factor-BB and transforming growth factor-β1 concentrations were highest in gels and releasates derived from 1,000 × 10³ platelets/μL.

The inclusion of platelets in FGs altered the architecture and increased the growth factor content of the resulting scaffold. Platelets may represent a useful means of modifying these gels for applications in veterinary and human regenerative medicine.