To investigate whether the cartilage regenerative effects of intra-aricular platelet-rich plasma (PRP) are different, according to the severity of osteoarthritis (OA), in a collagenase-induced knee OA rabbit model.
New Zealand white rabbits (N=21) were randomly divided into three groups. Three different doses (0.25 mg, group 1; 0.5 mg, group 2; and 1.0 mg, group 3) of collagenase were injected twice into both knees of each group under an ultrasound guidance. The mean platelet concentration of the PRP fraction was 2,664±970×103/µl and was enriched 8.2-times, compared with the whole blood. PRP (0.3 ml) was injected into the left knee and saline (0.3 ml) into the right knee at 4 weeks, and macroscopic and histological scores of both injected knees were evaluated at 9 weeks after the first collagenase injection.
Macroscopic and histological scores of group 3 were significantly higher than those of group 1 and 2 (p<0.05). Macroscopic and histological scores of the PRP-injected knees were significantly lower than those of the saline-injected knees, in all groups (p<0.05). Differences of gross morphologic and histologic scores between saline- and PRP-injected knees in group 3 were significantly higher than those in group 1 and 2 (p<0.05).
Intra-articular PRP injection influences cartilage regeneration in all severities of rabbit knee OA, and the cartilage regenerative power of PRP injection in moderate knee OA was greater than that in mild or very mild OA. A large preclinical trial is needed to establish the validity of our study.
Citations
Objective: Ultrasound has been therapeutically applied for pain control in rheumatoid arthritis although little physiologic effects of sonication on rheumatoid tissue were known. This investigation was conducted to determine the effects of sonication on the cell proliferation and matrix metalloproteinase (MMP) production of cultured fibroblast like synoviocytes (FLS) derived from synovial tissues of rheumatoid arthritis.
Method: Pulsed ultrasound (1.0 MHZ, 20 msec on, 80 msec off) with varying intensities (0, 0.1, 0.25, 0.5, 0.75, 1.0 W/cm2) was applied to experimental cell groups growing as monolayers in culture plates for varying durations (0, 30, 90, 180 seconds) in the presence and absence of interleukin-1β (IL-1β).
Results: There were no significant differences in thymidine incorporation between 0, 30, 90 and 180 second sonication groups with 0.5 W/cm2 after 1 day and 2 days. There were no significant differences in thymidine incorporation between 0, 0.1, 0.25, 0.5, 0.75, 1.0 W/cm2 sonication groups 1 day and 2 days after 90 second sonication. There were significant increase in MMP-1 (p=0.025) and MMP-3 production (p=0.000) of FLS after sonication in the absence of IL-1β but there were no significant differences in MMP-1 and MMP-3 production in the presence of IL-1β. And MMP-1 and MMP-3 production were increased significantly in the presence of IL-1β but not than in the absence of IL-1β.
Conclusion: While comparisons made between a limited number of FLS cell lines must be open to question, the overall consistency of the findings suggest sonication with nonthermal effect is not the contraindication in rheumatoid arthritis treatment but further study is needed in vivo in animal and in clinical studies.