Fundamental Study On The Property Changes Of The Subchondral Bone In The Occurrence And Development Of Spontaneous Osteoarthritis Of Hartley Guinea Pig

Objective: osteoarthritis(OA)is a common chronic disease of bone and joint.It is one of the important causes of joint pain and dysfunction.Articular cartilage is a common disease characterized by cartilage destruction and wear,subchondral bone thickening and sclerosis,osteophyte formation,and synovitis of different degrees and thickening of articular capsule.Subchondral bone and cartilage are the basic structures and functional units of joints.They maintain the structure and function of joints through biological and biomechanical connections.In recent years,the study found that the subchondral bone in osteoarthritis play an important role in the development and changes of the subchondral bone may be the initial factor in the pathogenesis of osteoarthritis,this study aims to investigate the spontaneous osteoarthritis in Hartley guinea pigs(osteoarthritis,OA)disease occurrence and development process,and the relationship between cartilage and the subchondral bone plate properties and articular cartilage degeneration.Method: 42 Dunkin-Hartley(DH)guinea pigs were divided into 7 time points were knee specimens,the experimental animal every sampling time is 6,the natural feeding condition,were killed in 1 month old,2 month old,3 month old,4 month old,6 month old,9 month old and 12 months of age,random selected specimens of knee joint,using safranin O fast green(Safranine O-Fast Green)for histological examination and staining method,and the modified Mankin scoring system to evaluate the degree of cartilage degeneration,changes in bone microstructure of Micro-CT tibial plateau under soft bone scan.Results: histological and modified Mankin score showed that in 1 month old and 2 month old,the joint surface cartilage cells and matrix staining were normal and osteoarthritis began to appear.At the age of 3 months(osteoarthritis,OA)kind of change,and with the growth of months,cartilage degeneration degree increased gradually.At the age of 12 months,reach the moderate degeneration of cartilage.The Micro-CT scans showed that in the 7 time points,subchondral cancellous bone,BV/TV(bone volume / total volume)there was no significant difference between the change of BS/BV(bone surface / bone volume)Tb.Th(the mean trabecular thickness),Tb.N(the average trabecular number),Tb.Sp(trabecular separation)with the increase of the month there were changes have significant difference,and at the age of 4-6 months,changes in these indicators suggest that the emergence of a turning point,gradually osteoporosis performance from the beginning of age appear gradually hardened steering performance.The change of the subchondral bone plate is the appearance of thickening and hardening gradually with the increase of the age of the month.Conclusion: 1.When the DH guinea pigs were in the natural growth state,at the age of 3 months,there was OA like change on the articular surface of the knee joint,and the OA gradually increased with the increase of the age of the month.2.The subchondral bone plate of knee joints gradually thickened and hardened in the progress of OA.3.In the OA process of knee joints,the changes in the subchondral cancellous bone change from the gradual osteoporosis of the beginning to the gradual hardening.