| Objective:To observe the effect of Abaloparatide on subchondral bone and cartilage of knee in rats,and to explore the mechanism of Abaloapratide delaying the progression of Knee Osteoarthritis.Methods:24 3-month-old male SD rats weighing 280±20g were divided into sham operation group,Osteoarthritis group,and ABL group,8 rats pervgroup.The OA model was established by ACLT in the Osteoarthritis group,and the ABL group,and joint capsule was sutured in sham operation group.ABL group received subcutaneous injection of Abaloparatide solution,25μg/kg,25μg/ m L,7 times a week for 12 weeks from one week after surgery.The model group was subcutaneously injected with 1ml/kg normal saline for the same time and the sham group were fed without intervention.After 12 weeks of intervention,all rats were sacrificed.Blood samples were collected from the orbit.We detected serum levels of TNF-α,IL-1β and IL-6 by ELISA.We stained left knee joints of rats with HE and saffrin-solid green staining to observe the full-thickness structure and cell morphology of cartilage,and Mankin score was performed.Micro CT was used to observe the three-dimensional morphology of tibial subchondral bone of right knee and its histomorphometric parameters.The relative expression levels of MMP-13,Wnt5 a,Wnt10b and β-catenin in the right femoral condyle of rats were detected by Western blot.Results:1.ELISA: compared with sham operation group,the levels of serum TNF-α,IL-1β and IL-6 in osteoarthritis group increased,but there was no significant difference(p > 0.05,p > 0.05,p > 0.05).Compared with osteoarthritis group,the levels of serum TNF-α,IL-1β and IL-6 in ABL group decreased,but there was no significant difference(P > 0.05,P > 0.05,P > 0.05).2.Histopathology: Compared with the sham operation group,the mankin score of rats in osteoarthritis group was higher and the difference was statistically significant(P < 0.01),and cartilage defects and osteophytes were formed in sections.Compared with osteoarthritis group,the mankin score of rats in ABL group was lower and the difference was statistically significant(P < 0.05),with less cartilage damage and clearer tissue structure.3.Bone morphological measurement parameters: Compared with sham operation group,BV,BV/TV,Tb.N,BMD in osteoarthritis group decreased and the difference was statistically significant(P < 0.05,P <0.001,P < 0.01,P < 0.001),while Tb.Th,Tb.Sp increased,among which TB.Compared with osteoarthritis group,BV,BV/TV,Tb.N,Tb.Th,BMD in ABL group increased with statistical differences(p < 0.001,p < 0.001,p < 0.001,p < 0.05,p < 0.001),while Tb.Sp decreased with differences.4.Micro-CT 2D and 3D imaging: There was no obvious widening of trabecular space in two-dimensional plain scan sham operation group.In some areas of osteoarthritis group,trabecular space was obviously widened and bone sclerosis was observed.In ABL group,the trabecular space was widened and distributed sparsely.The bone surface of sham operation group was smooth.In osteoarthritis group,three-dimensional imaging showed bone defect,uneven cartilage surface and a large number of osteophytes around tibial plateau.In ABL group,some bone surfaces were rough,no obvious defects were found,and osteophytes were visible at the edges.5.Western blot: Compared with sham operation group,the expression of MMP-13 in the right femoral condyle of osteoarthritis group was significantly higher and the difference was statistically significant(P < 0.01),while the expression of Wnt5 a,Wnt10b and β-Catenin had no significant difference(P > 0.05,P > 0.05,P > 0.05).In ABL group,the expressions of Wnt5 a,Wnt10b and β-Catenin in right femoral condyle increased significantly(p < 0.05,p < 0.001,p < 0.001),while the expression of MMP-13 decreased significantly(p < 0.05).Conclusion: 1)Abaloparatide can improve the subchondral bone microstructure of ACLT rats,inhibit cartilage degeneration and delay the progression of knee osteoarthritis.Wnt/β-catein pathway may be involved in this process. |
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