| Part One The experimental model of lumbar facet joint degeneration in ovariectomized ratsObjective: To investigate the characteristics and mechanism of FJ cartilage and subchondral bone degeneration after estrogen deficiency in ovariect-omized rats.Methods: Thirty three-month-old female Sprague Dawley(SD)rats were randomly divided into normal group,sham group and OVX group(10 rats in each group).In sham group,the ovaries were exposed by incision,but the wounds were closed by suture without resection,and the ovariectomy(castration)was performed in OVX group.All rats were euthanized 12 weeks after operation.The sections of L4-L5 facet joint of spine were taken and further processed.The histological changes of FJ cartilage were observed by toluidine blue staining and the scores were made according to the microscopic manifestations of this section.Micro CT was used to scan the subchondral bone microstructure of L4-L5 facet joint of spine and analyze its parameters.The serum CTX-1 concentration in the abdominal aorta blood of castrated rats was measured and analyzed by enzyme linked immunosorbent assay(ELISA).Results: After toluidine blue staining,the cartilage surface of Normal group and Sham group was smooth,regular,without cracks and wear;the morphology and arrangement of chondrocytes were normal,without decrease in number;the extracellular matrix of cartilage was stained evenly,without loss of staining.In OVX group,there were obvious degeneration of cartilage,cracks on the surface of joint,some of the cracks were as deep as the middle cartilage,and the number of local chondrocytes decreased significantly.The histological score of OVX group was significantly higher than that of Normal group and Sham group(P < 0.05).Compared with Normal group and Shamgroup,CTX-1 in OVX group increased(P < 0.05).The results of micro CT scanning showed that BMD,BV / TV and TB.Th in OVX group decreased(P< 0.05),but TB.SP increased(P < 0.05)compared with Normal group and Sham group.There was no significant difference in TB.N between the two groups(P > 0.05).Part Two The effect of alendronate on the degeneration of articular cartilage of lumbar facet in ovariectomized ratsObjective: To study the effect of alendronate(ALN)on FJ articular cartilage in ovariectomized rats.Methods: Thirty three-month-old female Sprague Dawley(SD)rats were randomly divided into Sham group,CI group and ALN group(10 rats in each group).Sham group rats were treated with ovariectomy,but without ovariectomy,they were sutured to close the wound,they were treated with sham operation;CI group and ALN group rats were treated with ovariectomy.The rats in CI group were treated by subcutaneous injection of normal saline.ALN group was treated by subcutaneous injection of ALN at a dose of 70 μ g/ kg once a week.All rats were euthanized 12 weeks after treatment.Toluidine blue staining was used to observe the histological changes of L4-L5 FJ cartilage in the spinal column of ovariectomized rats.The expression data of Caspase-3,ADAMTS-4,MMP-13 and AGG in L4-L5 FJ cartilage of castrated rat spine were collected and analyzed by immunohistochemistry.The concentration of comp in serum of castrated rats was analyzed by enzyme linked immunosorbent assay(ELISA).Correlation analysis was used to analyze the correlation between serum COMP concentration and modified Mankin score.Results: Under the microscope after toluidine blue staining,there was no obvious damage to the FJ cartilage of the lumbar vertebrae in the Sham group,the surface of the cartilage was smooth,regular,without cracks and wear;the morphology and arrangement of the chondrocytes were normal,without any decrease in the number;the extracellular matrix of the cartilage was stained evenly,without loss of staining.In CI group,the degeneration of FJ cartilagewas obvious,which was characterized by irregular surface and small fissures.After ALN injection,the degree of cartilage injury,the morphology and arrangement of chondrocytes and the staining of cartilage extracellular matrix in OVX rats were improved.The modified Mankin score of CI group was significantly higher than that of Sham group and ALN group(P < 0.05).There was no significant difference between Sham group and ALN group(P > 0.05).The thickness of FJ cartilage in CI group was significantly smaller than that in Sham group(P < 0.05).Compared with CI group,FJ cartilage in ALN group was significantly thickened(P < 0.001),but there was no significant difference between ALN group and Sham group(P > 0.05).Compared with Sham group,the expression of aggrecan and ADAMTS-4,MMP-13 and Caspase-3 in CI group were significantly lower(P < 0.01),and significantly higher(P < 0.001).Compared with CI group,the expression of ADAMTS-4,MMP-13 and Caspase-3 in ALN group decreased significantly(P < 0.001),and the expression of aggrecan increased significantly(P < 0.05).The serum COMP concentration in CI group was significantly higher than that in Sham group(P < 0.01).There was no significant difference between ALN group and CI group or Sham group(P > 0.05).There was a significant negative correlation between serum COMP and cartilage thickness(r =-0.380,P = 0.038).Part three The effect of alendronate sodium on subchondral degeneration of lumbar facet joint in ovariectomized ratsObjective: To study the effect of alendronate(ALN)on the subchondral bone of lumbar FJ in ovariectomized rats.Methods: Thirty three-month-old female Sprague Dawley(SD)rats were randomly divided into Sham group,CI group and ALN group(10 rats in each group).Sham group rats were treated with ovariectomy,but without ovariectomy,they were sutured to close the wound,they were treated with sham operation;CI group and ALN group rats were treated with ovariectomy.The rats in CI group were treated by subcutaneous injection of normal saline.ALN group was treated by subcutaneous injection of ALN at a dose of 70 μ g /kg once a week.All rats were euthanized 12 weeks after treatment.Micro CT was used to scan the subchondral bone microstructure of L4-L5 facet joint of spine and analyze its parameters.Results: Compared with Sham group,BMD(P < 0.001),BV / TV(P <0.001),TB.Th(P < 0.05)and TB.Sp(P < 0.001)in CI group were significantly lower and higher.Compared with CI group,BMD,BV / TV,TB.Th and TB.SP of ALN group were significantly higher and lower(P < 0.001)Conclusions:1.The animal model of estrogen deficiency made by ovariectomized rats showed that after 12 weeks of ovariectomy,the lumbar FJ of rats degenerated.In degenerative lumbar FJ,both cartilage and subchondral bone showed degeneration.2.ALN can protect FJ cartilage of ovariectomized SD rats,and its mechanism may be related to ALN maintaining cartilage metabolism balance and inhibiting chondrocyte apoptosis.In addition,serum COMP may have the potential to predict FJ OA.3.ALN also has protective effect on FJ subchondral bone in ovariectomized SD rats.The mechanism may be related to ALN reducing the activity of subchondral bone remodeling and decreasing the transformation of subchondral bone. |
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