Regenerative effects of hyperbaric oxygen therapy and platelet-rich plasma on the osteochondral defects of rats

Abstract

Objectives: This study aims to investigate the effects of hyperbaric oxygen (HBO) therapy and platelet-rich plasma (PRP) on the regeneration of osteochondral defects of the rats, and the synergistic effect of this combined treatment.

Materials and methods: This randomized, controlled, and interventional animal study was conducted between May 2014 and August 2014 Osteochondral regeneration was evaluated in four treatment groups (control, PRP, HBO, and HBO+PRP groups) at the 30th day after iatrogenic injury. Thirty-two female Wistar albino rats (weighing 248-305 g) underwent arthrotomy and osteochondral surgery on left knees. The regenerations of defects were then examined histologically by the modified version of O'Driscoll score.

Results: Groups that were treated with either HBO or PRP alone regenerated significantly better than the control group (p=0.01), while no significant difference was found between the HBO- and PRP-treated groups (p>0.05). The defects in group 4 (treated with both HBO and PRP) regenerated significantly better than the control group, the HBO-treated group alone, and the PRP-treated group alone (p=0.01).

Conclusion: The results of this study showed a synergistic effect of HBO and PRP on knee cartilage regeneration. However, the possible underlying mechanisms should be the subject of future researches. The aggregation and activation of growth factors released from platelets whose activation is increased in the hyperbaric environment may explain this effect. This may result in a better regeneration than the effect of PRP or HBO alone.

Figure 1. (a) Defect is filled with fibrous tissue with incomplete surface epithelial development. Irregularity is remarkable (40x magnification, hematoxylin-eosin [H-E] staining, control group). (b) Defect contains fibrous tissue and cartilage tissue, and there is very little formation of cartilage and new bone at base. Surface appears to be more clearly closed and surface epithelium is regularly proliferated (40x magnification, H-E staining, hyperbaric oxygen [HBO] and platelet-rich plasma [PRP] groups). (c) Depth of defect is considerably reduced with cartilage from edges and base and new bone productions, as well as regular state of surface (40x magnification, H-E staining, HBO plus PRP group).