Molecular Mechanism Of Osteoarthritis And Changes Of Type Ⅱ Collagen Metabolite Concentration

Osteoarthritis(OA)is a chronic,degenerative bone and joint disease that often occurs in aging animals,also known as degenerative arthritis and proliferative arthritis.It is characterized by progressive degeneration of cartilage and formation at the edge of the cartilage,and remodeling of the subchondral bone.The main clinical manifestations are joint swelling,chronic pain,stiffness and limited mobility.OA is often found in older animals,and the knee joint is the most common place of OA.The diagnosis of OA is usually based on imaging examinations(such as X-ray films)and clinical symptoms in veterinary clinical work.Currently,there are still no biomarkers that can effectively diagnose OA.Previous studies focused on a single marker at a certain point in time,and did not study the trends of these markers with the OA.Therefore,this study carried out in vitro,in vivo and clinical trials,using SD rats and cows as research subjects to study the mechanism of OA cartilage injury and the concentration of PⅡCP,CTX-Ⅱ and C2C organisms during the pathogenesis of OA.It provides a theoretical basis for screening OA molecular markers,and realizes the evaluation and early diagnosis of OA disease,which provides a theoretical basis for dairy cow OA rapid diagnosis technology and increases production performance.The study simulates the occurrence of OA by an in vitro and in vivo method.The in vitro study used 14-24 d young rats for cartilage culture,and the cells were starved before the test to synchronize them.Thereafter,IL-1β was added to chondrocytes at 0h,12 h,24 h and 48 h to induce an inflammatory model.Western-blot method were used detected NF-κb signal pathway and matrix degradation related products,such as MMP-3,MMP-13,i NOS,p65 and p-p65 protein express;Nuclear translocation of p65 were detected immunofluorescence;The concentration of NO was detected biochemical reagents box;the change of type Ⅱ collagen-related molecular markers(CTXⅡ,C2C and PⅡCP)in the cell culture supernatant was detected by ELISA,and the mechanism of cartilage damage during OA and the significant index of initial screening change were explored.The in vivo test was divided into two groups.The sham operation group(Sham group)was sutured only after the joint capsule was opened.The operation group(ACLT group)cut the anterior cruciate ligament after the capsule was opened.The two groups were sampled at 0,2,4,6,8,and 10 weeks after surgery.The right hind limb tibia was used to make histopathology and Safranin O section staining.Serum was uesed detect the concentration of CTX-Ⅱ,C2C,and PⅡCP.After using the Daishan dairy farm cows,they were divided into two groups: normal group and OA group.Serum was used to detect the concentration changes of CTX-Ⅱ,C2C and PⅡCP.The Spearman method was used to analyze the association of markers with severe disease,and the ROC curve was used to analyze the value of markers for the diagnosis of OA.The result found:1.IL-1β can induce activation of the NF-κb pathway,which in turn causes chondrocyte OA.2.,Activation of NF-κb pathway can induce the increase of MMP-3,MMP-13,i NOS expression,and increase the concentration of CTX-Ⅱ and C2C,leading to the destruction of extracellular matrix in chondrocyte OA.3.The cartilage matrix damage increased with time,the concentrations of serum CTX-Ⅱ and C2C also increased,and the cartilage OARSI score changes correlated with the concentration trends of CTX-Ⅱ and C2C in the ACLT model.4.ROC analysis showed that CTX-Ⅱ and C2C were used to diagnose bovine OA with higher AUC values and greater diagnostic value.The results showed that the NF-κb pathway was activated after IL-1β stimulated chondrocytes,and the downstream pathway was induced to induce cartilage damage,resulting in increased degradation of type Ⅱ collagen.Moreover,the concentration of C2C and CTX-Ⅱ in serum of ACLT rats increased with the severity of cartilage damage,which could be used as a potential molecular marker for the diagnosis of OA.In addition,the content of C2C and CTX-Ⅱ in OA bovine serum also increased.For the diagnosis of dairy cows OA value is greater.