Activated platelet rich plasma modulates the proliferation, apoptosis and matrix synthesis driven by growth factors in osteoarthritic chondrocytes: an in vitro study

Introduction Activated platelet‐rich plasma (aPRP) reduces inflammation and promotes regeneration in osteoarthritic knee joints. It may exert therapeutic effects on osteoarthritic chondrocytes (OACs) compared with healthy chondrocytes (HCs) by promoting cell proliferation, reducing autophagy‐related vesicles and inhibiting apoptosis through modulation of intracellular signaling pathways. The aim of this study was therefore to evaluate cell viability, apoptotic fate, extracellular matrix protein expression (collagen type II (COL2A1) and aggrecan (ACAN)), autophagy‐related vesicle production, and growth factor profiles, including TGF‐β and PDGF-BB, in HCs and OACs. Methods Mechanically aPRP‐S and PRP‐G using mini-beads, leukocyte-rich L‐PRP, leukocyte-poor P‐PRP and platelet-rich in growth factors (PRGF) were co-cultured with HCs and OACs for real-time proliferation analysis, apoptosis by flow cytometry, autophagy and related intracellular markers through immunofluorescent labeling, and the secretome profile by ELISA, aligned with their effective dose (ED50) and optimal ED50 time point. Results aPRPs at 2.7% in 2 h and PRGF at 1.8% in 3 h induced proliferation of OACs. PRGF reduced the apoptotic cell ratios of OACs. aPRPs and PRGF promoted COL2A1 and ACAN protein synthesis. Discussion The induction of proliferation of the OACs is a promising result that can be translated to clinical applications. aPRPs may have a stimulatory role in OACs. This role can be dose and preparation protocol dependent. aPRPs and PRGF can be preferred to stimulate COL2A1 synthesis and reduce apoptotic cell ratios in cultured OACs.