Published online Dec 18, 2015. doi: 10.5312/wjo.v6.i11.961
Peer-review started: April 11, 2015
First decision: June 24, 2015
Revised: September 8, 2015
Accepted: October 1, 2015
Article in press: October 8, 2015
Published online: December 18, 2015
AIM: To explore the effect of platelet-rich plasma on protein expression patterns of transforming growth factor-beta1 (TGF-β1) in cartilage following autologous osteochondral transplantation (AOT) in a rabbit knee cartilage defect model.
METHODS: Twelve New Zealand white rabbits received bilateral AOT. In each rabbit, one knee was randomized to receive an autologous platelet rich plasma (PRP) injection and the contralateral knee received saline injection. Rabbits were euthanized at 3, 6 and 12 wk post-operatively. Articular cartilage sections were stained with TGF-β1 antibody. Histological regions of interest (ROI) (left, right and center of the autologous grafts interfaces) were evaluated using MetaMorph. Percentage of chondrocytes positive for TGF-β1 was then assessed.
RESULTS: Percentage of chondrocytes positive for TGF-β1 was higher in PRP treated knees for selected ROIs (left; P = 0.03, center; P = 0.05) compared to control and was also higher in the PRP group at each post-operative time point (P = 6.6 × 10-4, 3.1 × 10-4 and 7.3 × 10-3 for 3, 6 and 12 wk, respectively). TGF-β1 expression was higher in chondrocytes of PRP-treated knees (36% ± 29% vs 15% ± 18%) (P = 1.8 × 10-6) overall for each post-operative time point and ROI.
CONCLUSION: Articular cartilage of rabbits treated with AOT and PRP exhibit increased TGF-β1 expression compared to those treated with AOT and saline. Our findings suggest that adjunctive PRP may increase TGF-β1 expression, which may play a role in the chondrogenic effect of PRP in vivo.
Core tip: Despite the prevalence of platelet rich plasma (PRP) in both practice and literature, there is a dearth of data exploring the specific factors crucial to its role as an adjunct to cartilage repair surgeries. Our results suggest that the increased expression pattern of transforming growth factor-beta1 in PRP-treated rabbit femoral condyles, compared to saline treated controls, is associated with enhanced cartilage repair at the graft-host interface following autologous osteochondral transplantation. Our results serve as an initial step in building a body of evidence behind the specific growth factors crucial to cartilage repair and promise to help us understand how formulations of PRP are effective in musculoskeletal healing.