Expression Of Matrix Gla Protein In Hartley Guinea Pig Model Of Spontaneous Knee Osteoarthritis And Its Relationship With Histological Progress Of OA

Objective: Osteoarthritis(OA)is a common chronic degenerative heterogeneous disease of joints in middle-aged and elderly people.At present,the cause of osteoarthritis is not completely clear,and it is related to many factors.Nowadays,the diagnosis and evaluation of OA are mainly based on the clinical symptoms and imaging manifestations of patients.Matrix Gla Protein(MGP)is a vitamin K-dependent protein.Recent studies have found that MGP plays an important role in the regulation of cartilage mineralization.The purpose of this study was to investigate the expression of MGP in articular cartilage and its relationship with the histological progression of articular cartilage degeneration in Hartley guinea pig model of spontaneous osteoarthrosis.To explore whether MGP can be used as a new biomarker of OA,and to lay an experimental theoretical foundation for understanding the potential pathogenesis of OA.Methods: Twenty-five Dunkin-Hartley(DH)guinea pigs were randomly assigned to five groups.Under the condition of natural adaptive feeding,they were killed at the age of 1 month,3 months,6 months,9 months and 12 months respectively.The knee joint specimens were randomly selected to observe the joint appearance and synovium of different age groups.Safranine O-Fast Green staining was used to observe the degeneration of articular cartilage in guinea pigs,and the modified Mankin system was used to evaluate the degeneration.Matrix Gla Protein(MGP)in articular cartilage of guinea pigs was detected by immunohistochemistry.Image-Proplus 6.0 was used to analyze the integraled optical density of MGP expression,and SPSS20.0 was used to analyze the data.Result: 1.Safranine O-Fast Green Staining and specimen observation showed that the surface of articular cartilage of DH guinea pigs in baseline group was smooth,chondrocyte and matrix staining were normal.The articular cartilage of 3-month-old DH guinea pigs began to show mild OA-like changes.With the increase of age,the degree of articular cartilage degeneration gradually increased,and the modified Mankin score increased significantly.The 12-month-old specimens showed severe cartilage degeneration.2.Immunohistochemical experiments proofed that the expression of MGP in articular cartilage increased significantly with the increase of age of guinea pigs(P < 0.05).IOD in BL group was 605.26(±352.81).IOD in 3-month-old group was 5352.00(±771.81);IOD in 6-month-old group was 8801.27(±1687.98);IOD in 9-month-old group was 13446.74(±3321.75);IOD in 12-month-old group was 16088.82(±2670.73).The experimental group expressed MGP significantly higher than BL group.There was no difference in MGP expression between 9-month-old group and 12-month-old group in moderate severe OA(P > O.05).3.The expression level of MGP in articular cartilage of DH guinea pigs was positively correlated with the modified Mankin score(r = 0.961,P < 0.01).Conclusion:1.There was mild degeneration of articular cartilage in DH guinea pigs at 3 months of natural growth.with the increase of month age,OA gradually aggravated.2.The expression of MGP in articular cartilage is related to the occurrence and development of spontaneous OA in DH guinea pigs,and is positively correlated with the progress of OA.