Biodegradable Gelatin Hydrogels Incorporating Fibroblast Growth Factor 2 Promote Healing of Horizontal Tears in Rabbit Meniscus

PurposeThe purpose of this study was to investigate the in vivo effects of gelatin hydrogels (GHs) incorporating fibroblast growth factor 2 (FGF-2) on meniscus repair in a rabbit model.MethodsFGF-2 was biologically stabilized by incorporation into GHs. This system enables FGF-2 to be released with its biologic activity intact. A total of 64 skeletally mature female Japanese white rabbits were used. A horizontal tear was made in the medial meniscus, and these tears were divided into 4 groups: GH-FGF, GH–no FGF, FGF (FGF-2 alone), and no treatment. The meniscus was evaluated histologically at 2, 4, 8, and 12 weeks after surgery. Cell density and the percentages of proliferating cell nuclear antigen–positive cells and terminal deoxynucleotidyl transferase–mediated dUTP nick-end labeling–positive cells were measured, and a scoring system ranging from 5 points (complete healing) to 0 points (no evidence of healing) was used.ResultsCell density was significantly higher in the GH-FGF group than in the other 3 groups at 2, 4, 8, and 12 weeks (P < .01). The percentage of proliferating cell nuclear antigen–positive cells was significantly higher whereas the percentage of terminal deoxynucleotidyl transferase–mediated dUTP nick-end labeling–positive cells was significantly lower in the GH-FGF group at 2 and 4 weeks after surgery (P < .05). At 4, 8, and 12 weeks after surgery, healing scores were significantly higher in the GH-FGF group (2.5 points, 2.7 points, and 3.0 points, respectively) than in the GH–no FGF group (1.3 points, 1.4 points, and 2.0 points, respectively) (P < .05).ConclusionsGHs incorporating FGF-2 significantly stimulated proliferation and inhibited the death of meniscal cells until 4 weeks, thereby increasing meniscal cell density and enhancing meniscal repair in a rabbit model.Clinical RelevanceGHs incorporating FGF-2 are able to enhance the healing of meniscal injury.