Favorable vocal fold wound healing induced by platelet-rich plasma injection

Objectives. To introduce a new injection material for vocal fold diseases, which could be readily translated to clinical practice, we investigated the effectiveness of platelet-rich plasma (PRP) injection on the injured vocal fold in terms of histological recovery. Methods. Blood samples were drawn from New Zealand White rabbits and PRP was isolated through centrifugation and separation of the samples. Using a CO₂ laser, we made a linear wound in the 24 vocal fold sides of 12 rabbits and injected each wound with PRP on one vocal fold side and normal saline (NS) on the other. Morphologic analyses were conducted at 2, 4, and 12 weeks after injection, and inflammatory response, collagen deposit, and changes in growth factors were assessed using H&E and masson trichrome (MT) staining and western blot assay. Results. PRP was prepared in approximately 40 minutes. The mean platelet concentration was 1,315,000 platelets/mm³. In morphological analyses, decreased granulation was observed in the PRP-injected vocal folds (P<0.05). However, the irregular surface and atrophic change were not difference. Histological findings revealed significant inflammation and collagen deposition in NS-injected vocal folds, whereas the PRP-injected vocal folds exhibited less (P<0.05). However, the inflammatory reaction and fibrosis were not difference. In western blot assay, increased amounts of growth factors were observed in PRP-injected vocal folds. Conclusion. Injection of injured rabbit vocal folds with PRP led to improved wound healing and fewer signs of scarring as demonstrated by decreased inflammation and collagen deposition. The increased vocal fold regeneration may be due to the growth factors associated with PRP.