The technique of articular rabbit cartilage roughness measurement and analysis of the effect of PRP in knee osteoarthritis therapy using atomic force microscopy

Hyaline cartilage undergoes degenerative-dystrophic changes with subsequent involvement of the subchondral bone. The purpose of this study was developing a new AFM-based method to articular rabbit cartilage roughness measurement, followed by an investigation of whether platelet-rich plasma therapy of knee osteoarthritis has a positive impact on mechanical properties of rabbit cartilage. The rabbits were randomly divided into two groups: the control group (N=6) and the patients (N=12). Saline (0.5 ml) and 10% surgical talc solution were injected into the right knee of 12 rabbits to induce osteoarthritis. Six rabbits underwent PRP therapy, while the other six did not receive treatment. The mechanical properties and the submicron surface morphology rabbit hyaline cartilage were investigated using atomic force microscopy (AFM). In the group of specimens worn out by induced osteoarthritis, the maximum arithmetic average of absolute values (Ra) change was a 23% increase; the maximum peak height (Rp) increased by over 100%, while the mean spacing between local peaks (S) increased by 26%, compared to healthy rabbit cartilage (p<0.05). In the group of specimens worn out by induced osteoarthritis and cured with PRP therapy, Ra increased by 13%; Rp increased by 33%, while S decreased by 77%, compared to healthy rabbit cartilage (p<0.05). It was found that the mechanical properties of hyaline cartilage deteriorate under the influence of simulated osteoarthritis. The results of PRP treatment in rabbits may constitute a step forward to further relevant studies involving OA patients.