# Effect of Reduced Centrifugation Time on Leukocyte, Platelet, and Growth Factor Levels in Platelet-Rich Fibrin (PRF) Prepared Using Low-Speed Relative Centrifugal Force (RCF): An Ex Vivo Study

## TL;DR

Shortening centrifugation time from 8 to 4 minutes improves the concentration of leukocytes, platelets, and growth factors in PRF, potentially enhancing its regenerative properties for periodontal applications.

## Contribution

The study demonstrates that reducing centrifugation time improves cellular and growth factor yields in PRF, offering a more efficient protocol for clinical use.

## Key findings

- Reducing centrifugation time to 4 minutes significantly increased leukocyte and platelet concentrations.
- VEGF levels showed a near-significant rise, while TGF-β exhibited a non-significant upward trend.
- The shorter protocol suggests improved cellular retention and growth factor release.

## Abstract

Background: Platelet-rich fibrin (PRF), a second-generation autologous biomaterial, enhances periodontal regeneration through its fibrin matrix, which is enriched with leukocytes, platelets, and growth factors such as vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-β). Centrifugation parameters critically influence the regenerative composition of PRF, with low-speed relative centrifugal force (RCF) protocols improving both cellular and molecular yields. However, the impact of centrifugation time remains underexplored. This study investigates whether reducing centrifugation time from 8 to 4 minutes at 44 g (600 rpm) optimizes PRF’s regenerative profile for periodontal applications.

Methods: Peripheral blood from 10 healthy male volunteers (aged 20-30 years) reporting to a tertiary care center was processed into fluid PRF using two protocols: 8-minute and 4-minute centrifugation at 600 rpm. Leukocyte and platelet concentrations were quantified via flow cytometry, while VEGF and TGF-β levels were measured using enzyme-linked immunosorbent assay (ELISA) at 1 and 24 hours post-clotting. The Wilcoxon signed-rank test assessed differences between protocols (p ≤ 0.05).

Results: Reducing centrifugation time to 4 minutes significantly increased leukocyte (median: 0.04-0.07 ×10³ cells/µL, p = 0.008) and platelet (median: 578-691 ×10³ cells/µL, p = 0.005) concentrations. VEGF levels showed a near-significant rise (median: 4.19-6.10 pg/mL, p = 0.051), while TGF-β exhibited a non-significant upward trend (median: 35.57-36.43 ng/mL, p = 0.594). These enhancements suggest improved cellular retention and growth factor release.

Conclusion: A 4-minute centrifugation at 600 rpm suggests improved cellular retention and trends toward higher growth factor concentrations by enhancing leukocyte, platelet, and VEGF concentrations, with a modest TGF-β increase. This protocol offers potential biochemical enhancement with improved chair-side efficiency, warranting further clinical validation.