Effect of platelet-rich plasma and concentrated growth factor on survival of ultra-diced cartilage grafts in a rabbit model

Objective: The aim of this study is to investigate histopathologically the viability of the ultra-diced cartilage by wrapping it with various autobiological sheaths such as platelet-rich plasma and concentrated growth factor in an experimental animal model. In addition, to determine the effects of both materials on cartilage tissue viability and resorption. Materials and Methods: After the approval of Bezmialem Vakıf University Experimental Animals Ethics Committee, 14 New Zealand rabbits, 12 weeks old, with an average of 3.5 kg, were divided into 3 groups. Twenty cc of venous blood was collected from each rabbit. Then, 10 cc of blood was used to obtain platelet-rich plasma (PRP) and the other 10 cc of blood was used to obtain concentrated growth factor (CGF). Afterwards, a ultra-diced cartilage was prepared from the cartilage taken from each rabbit's ear. This ultra-diced cartilage was divided into three and the first group was utilized plainly, the second group was wrapped with platelet-rich plasma, and the third group was wrapped with concentrated growth factor. These three grafts were placed surgically in the paraspinal region in rabbits. After 3 months, the grafts on the back of the rabbits were removed and taken for histopathological examination. In microscopic examinations, chondrocyte loss, inflammation, fibrosis, cartilage fragmentation and calcified area formations in the lacunae were evaluated semi-quantitatively regarding the histopathological changes in the cartilage tissue. In addition, peripheral cell proliferation in the cartilage tissue, vascularization in the connective tissue, proteoglycan increase in the cartilage tissue matrix and the amount of connective tissue formed between the cartilage tissue pieces were evaluated semi-quantitatively as an indicator of cartilage tissue viability and regeneration. Evaluation parameters range from 0 to 4 (0= 0-1% none, 1= 1-25% minimal, 2= 26-50% moderate, 3= 51-75% moderate-severe, 4= 76-100% severe) was determined under microscopic views. As a result of the measurements, the measurements related to the histopathological changes were grouped among themselves and determined as the "histopathological score", and the measurements related to the tissue viability and regenerative capacity were grouped together and determined as the "regenerative score". Results: In the histopathological score comparison between the groups, statistically significant reductions were observed in the CGF-wrapped ultra-diced cartilage (p<0.0001) and PRP-wrapped ultra-diced cartilage (p<0.0275) groups compared to the ultra-diced cartilage group alone. There was no statistically significant difference in terms of histopathological score between the CGF-wrapped and PRP-wrapped ultra-diced cartilage groups (p<0.1605). In the regenerative score comparison between the groups, statistically significant increases were observed in the CGF-wrapped ultra-diced cartilage (p<0.0001) and PRP-wrapped ultra-diced cartilage (p<0.0159) groups compared to the ultra-diced cartilage group alone. A statistically significant (p<0.0137) regenerative score increase was seen in the CGF-wrapped ultra-diced cartilage group compared to the PRP-wrapped ultra-diced cartilage group. Conclusion: Our study is the first to investigate the ultra-diced cartilage in an experimental animal model. Histological examination has shown that wrapping the ultra-diced cartilage with CGF or PRP increases cartilage viability and reduces cartilage resorption.