| Part one The experimental study of the role of medial meniscectomy on knee cartilage of DH guinea pigsObjective: To evaluate the histological changes of medial meniscectomy(MNX) induced cartilage degeneration in Dunkin Hartley(DH) guinea pigs, and clarify which phase of OA progression it is represented.Methods: Twelve 3-month-old male DH guinea pigs were randomly divided into two groups(n = 6), Sham group and MNX group, animals were received sham operation or medial meniscectomy, respectively. All animals were sccrificed 12 weeks post operation, then the joints were evaluated by OARSI histological scoring system, OA-related proteins were assessed by immunohistochemical techniques, and serum IL-1β concentrations were tested by ELISA.Results: 1 Bodyweights for animals from both groups were growing through time, there were no statistical significance were observed between groups at any time points. 2 Serum IL-1β concentrations were not found to be significantly different between groups. 3 Joints from MNX group were severely degenerated post operation, the cartilage thicknesses were significantly reduced compared to Sham group(P < 0.05). The results indicate OARSI total scores with CS, PG, CL and OST subsets in MNX group were siginificantly higher than Sham group(P < 0.05). 4 The expression level of AGG in cartilage of MNX group was significantly reduced compared to Sham group, however, the expression level of MMP-13, ADAMTS4 and Caspase-3 were significantly up-regulated(P < 0.05). The ratio of AGG/ADAMTS4 and Col-II/MMP-13 were both significantly lower in MNX group, however, the ratio of Col-II/AGG was significantly higher than Sham group(P < 0.05). Part two The protential effects of PTH(1-34) on degenerated cartilage in MNX induced knee degeneration of DH guinea pigsObjective: Celecoxib(CLX) was introduced as positive control, to study the effects of parathyroid hormone(1-34)(PTH(1-34)) on cartilage degeneration in MNX induced OA model of DH guinea pigs.Methods: Twenty-four 3-month-old male DH guinea pigs were randomly divided into four groups(n = 6), Sham group MNX+NS group, MNX+CLX group and MNX+PTH group, animals were respectively received sham operation for Sham group or medial meniscectomy for MNX groups. Meniscectomized animals began 12 weeks of treatment by subcutaneous injection of PTH(1-34)(24 mg/kg, 5 days/week), oral administration of CLX(20 mg/kg, daily), or normal saline for MNX group. All animals were sccrificed, then the joints were evaluated by OARSI histological scoring system, OA-related proteins were assessed by immunohistochemical techniques, and serum IL-1β concentrations were tested by ELISA.Results: 1 Bodyweights for animals from each group were growing through time, there were no statistical significance were observed between any two groups at any time points. 2 Serum IL-1β concentrations were not found to be significantly different between any two groups. 3 Joints from MNX+NS group were severely degenerated post operation, the cartilage thicknesses were significantly reduced compared to Sham group, however, cartilage thickness in MNX+CLX group was significantly thicker than MNX+NS group, and it is thicker in MNX+PTH group than MNX+CLX group(P < 0.05). The results indicate OARSI total scores with CS and PG subsets in MNX+CLX group and MNX+PTH group were both siginificantly lower than MNX+NS group(P < 0.05). 4 The expression level of AGG in cartilage of MNX+NS group was significantly reduced compared to Sham group, however, the expression level of MMP-13, ADAMTS4, Caspase-3 and Periostin were significantly up-regulated(P < 0.05). The expression level of ADSMTS4 and Periostin in MNX+CLX group were siginificantly lower than MNX+NS group. The expression level of AGG in MNX+PTH group was significant higher than both MNX+NS group and MNX+CLX groups, however, the expression level of ADAMTS4, Caspase-3, MMP-13 and Periostin were significantly lower than MNX+NS group. The ratio of AGG/ADAMTS4 and Col-II/MMP-13 were both significantly lower in MNX group, however, the ratio of Col-II/AGG was significantly higher than Sham group(P < 0.05). The ratio of AGG/ADAMTS4 was significantly higher than MNX+NS group, the ratio of Col-II/MMP-13 was significantly higher than both MNX+NS group and MNX+CLX group, and the ratio of Col-II/AGG was significantly lower than MNX+NS group(P < 0.05). Part three The protential effects of PTH(1-34) on subchondral bone inMNX induced knee degeneration of DH guinea pigsObjective: CLX was introduced as positive control, to study the effects of PTH(1-34) on subchondral bone in MNX induced OA model of DH guinea pigs.Methods: Twenty-four 3-month-old male DH guinea pigs were randomly divided into four groups(n = 6), Sham group MNX+NS group, MNX+CLX group and MNX+PTH group, animals were respectively received sham operation for Sham group or medial meniscectomy for MNX groups. Meniscectomized animals began 12 weeks of treatment by subcutaneous injection of PTH(1-34)(24 mg/kg, 5 days/week), oral administration of CLX(20 mg/kg, daily), or normal saline for MNX group. All animals were sccrificed, then the subchondral bone of load-bearing area of medial tibial plateau were scanned by MicroCT technique, the bone mass and structure were evaluated by the following parameters: bone mineral density(BMD), bone volume ratio(BV/TV), trabecular number(Tb.N), trabecular spacing(Tb.Sp), trabecular thickness(Tb.Th), structure model index(SMI), and degree of anisotropy(DA).Results: The results of bone mass indicate BMD of MNX+NS group was significantly lower than Sham group, however, BMD of MNX+PTH group was significantly higher than MNX+NS group(P < 0.05). The results of morphological parameters indicate BV/TV and Tb.Th in MNX+NS group were significantly reduced compared to Sham group, while Tb.Sp and SMI were significantly increased(P < 0.05). Compared to MNX+NS group, no significant changes were observed in MNX+CLX group, however, those morphological parameters mentioned above were all significantly recoverd at different levels(P < 0.05).Conclusion:1 Medial meniscectomy could result in rapid degeneration of cartilage in medial tibial plateau from operated knee of DH guinea pigs in 12 weeks post operation, the cartilage and subchondral bone changes of this model reflect the pathological changes in early phase of OA.2 Compared with CLX, PTH(1-34) could significantly alleviate the degeneration progress of cartilage more effectively. This may be abscribed to the effects of PTH(1-34) to reduce the expression of apoptosis related protein and ECM degeneration related proteins, and promote the anabolic activities of ECM.3 PTH(1-34) could uniquely increase bone mass accompany by maintaining microarchitecture of subchondral bone, which were not observed in CLX treated animals. Therefore, these effects could contribute to the protective effects of PTH(1-34) on MNX induced knee degeneration of DH guinea pigs. |
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