[Quantification of papain-induced rat osteoarthritis in relation to time with the Mankin score]. / Siçanlarda papainle olusturulan osteoartritin Mankin skoru ile zamana bagli derecelendirilmesi.

OBJECTIVES: The aim of this study was to evaluate structural changes in relation to time with the use of the Mankin scoring system in papain-induced rat osteoarthritis. METHODS: Osteoarthritis was induced in 21 male Wistar rats by injecting an admixture of 4% papain (10 microl) and its activator 0.03 M cycteine (10 microl) into the right knee joints on the first, fourth, and seventh days. The same volume of sterile saline solution was injected into the left knees as controls. The rats were assigned to three groups equal in number and were sacrificed under high-dose ether anesthesia after one, two, and four weeks of the last papain injection, respectively. The study and control knee joints were removed and histologic changes in cartilage structure were assessed and quantified with the modified Mankin scoring system. RESULTS: Histologically, all papain injected knees exhibited irregularity and fibrillation in the superficial layer, decreased cell count and multilayering in transitional and radial zones, and no pannus formation. The modified Mankin scores were significantly higher compared to the control knees in all the groups (p<0.05), being 4.3+/-0.9, 6.9+/-1.3, and 10.4+/-1.9 in diseased knees, and 2.7+/-0.5, 4.0+/-0.8, and 4.4+/-1.0 in the control knees after one, two, and four weeks of the last papain injection, respectively. There was a significant difference between the Mankin scores of the rats sacrificed after one and four weeks of the last papain injection (p=0.0471). CONCLUSION: Findings observed after four weeks of papain injection seem to be consistent with early osteoarthritic changes. Our results may provide insight into therapeutic strategies for early osteoarthritis.

No beneficial effects of joint distraction on early microscopical changes in osteoarthrotic knees. A study in rabbits.

BACKGROUND: Although promising results have been reported, on the use of joint distraction in osteoarthrotic joints, the mechanism behind the effects has not yet been expland. MATERIAL AND METHODS: 24 rabbits were randomly divided into 4 groups and osteoarthrosis was induced by papain injection. The first group served as control and the others were treated by simple external fixation (group 2), articulated distraction (group 3) or nonarticulated distraction (group 4). RESULTS: Histologically, there was no significant difference between the first, the second and the third groups. However, osteoarthrosis increased in group 4. INTERPRETATION: We conclude that joint distraction has no beneficial effect on the osteoarthrotic cartilage in papain-induced osteoarthrosis, and nonarticulated distraction worsens the results.