Experimental study of platelet-rich-fibrin repairing wounds with exposed bone of rats

Abstract

Objective To investigate the effect of Platelet-rich-fibrin (PRF) in repairing wounds with exposed bone of rats. Methods 24 male Sprague-Dawley rats (250-300 g) were divided into 3 groups randomly using random number table, 8 rats in each group. A 1.5 cm×1.5 cm full-thickness wound was excised over the posterior scalp area and all the periosteum overlying the skull was removed. The wounds in the PRF group were covered with PRF clot; the wounds in the fat transplantation group were covered with the same volume of fat granules; the wounds in the control group were covered with the same volume of normal saline. The wound dressing was changed on day 4, 7, and 11, respectively. Quantitative assessment of bone exposure area was performed using Image J software.HE staining and Masson staining were used to evaluate the neovascularization and collagen deposition in wounds.The expression level of growth factors in granulation tissue in wounds was measured by Elisa. Results On day 4, the bone exposure rate was 57.99%±11.29% in the PRF group, 45.92%±9.55% in the fat transplantation group; and 77.73%±5.57% in the control group. On day 7, the bone exposure rates of the three groups were 4.29%±2.28%, 29.52%±6.33% and 36.90%±8.43%, respectively. While on day 11, only the exposed wounds in the PRF group were completely covered by granulation tissue. There were different degrees of bone exposure in the fat transplantation group and the control group, about 10.15%±1.49% and 21.69%±2.40%, respectively. The exposed area of wound bone in the PRF group was significantly smaller than that in the control group at each time point (P<0.01). On day 7 and day 11, the bone exposure ratio of the PRF group was significantly lower than that of the fat transplantation group, while on day 4, the bone exposure ratio of the fat transplantation group was significantly lower than that of the PRF group (P<0.001). HE results showed that the neovascularization density in the PRF group(10.37%±0.49%) was significantly higher than that in the fat transplantation group(4.86%±0.83%)and the control group(2.9%1±0.31%) (P<0.05). Masson staining showed that the collagen fibers in the PRF group were the most abundant. Elisa results showed that growth factor levels in the PRF group were significantly increased on day 11, and the differences were statistically significant compared with the fat transplantation group and the control group(P<0.05). Conclusions PRF as a convenient therapy method can accelerate wound healing of exposed bone, shorten the period of treatment and reduce physical and economic burden of surgery. Key words: Platelet-rich fibrin; Wounds healing; Fat grafting; Granulation tissue