High-field MRI Manifestations Of Knee Osteoarthritis And Its Correlation With Cartilage Damage Factors

As the largest and most complex joint of the human body,the knee joint plays an important role in movement,weight bearing,load transfer,and provision of force couples for calf movement.It is classified as a pulley joint and consists of the patella,the lower end of the femur and the upper end of the tibia.The knee joint has fewer forms of exercise,mainly doing flexion and extension exercises,but in the semi-flexion position,it can do rotation exercises.Because the structure of the knee joint is too complex and delicate,and it is located at the connecting part of the lower limbs,it bears a lot of force,thus easy to cause dislocation or fracture.Especially in competitive activities,ligament or meniscus injuries are also more common.In addition to trauma,knee diseases in the elderly are more common in degenerative diseases,such as osteoarthritis(OA),rheumatoid arthritis(RA)caused by articular cartilage destruction,joint deformities.Among them,osteoarthritis is a more common type of disease.However,among the elderly over 60 years old,more than half of the population has osteoarthritis imaging changes,and nearly half of them will have typical clinical manifestations.The incidence of osteoarthritis is increasing year by year,and its disability rate is high,exceeding 50%,which seriously affects the quality of life of patients and brings heavy social and economic burdens.Although most patients with osteoarthritis have advanced to the advanced stage of the disease at the time of clinical diagnosis,and the chances of reversing the disease are very limited at this time,from the perspective of the entire course of osteoarthritis,it usually takes more than ten years from asymptomatic to symptomatic.Therefore,it provides a long time window for clinical intervention,which may change its course.The etiology of osteoarthritis is multifaceted,and it is strongly related to risk factors such as mechanical overload,obesity,and joint damage.Therefore,early diagnosis and early treatment of joint damage and degeneration can be used to reduce the risk of osteoarthritis,and the characterization of the pre-disease state of osteoarthritis will be the key to supporting the transition from late disease remission to early prevention.Therefore,early detection and early treatment are the only effective intervention measures.This topic mainly starts with the study of m agnetic resonance and biomarkers,looking for the characteristics of early changes in osteoarthritis,and providing a theoretical basis for the diagnosis and treatment of osteoarthritis.This study can be divided into the following five aspects:the morphological characteristics of the rabbit knee osteoarthritis model at different development stages;the changes and significance of blood routine,CRP and erythrocyte sedimentation rate in the rabbit knee osteoarthritis model;the inflammation in the serum and knee joint fluid of the model rabbit;the expression of inflammatory factors/anti-inflammatory factors in peripheral blood and synovial fluid during the pathological changes of rabbit knee osteoarthritis model;the expression and significance of COL2,MMP3,MMP13 and TIMP-1 protein in knee cartilage tissue;the diagnostic value of 3.0T MRI in the classification of knee osteoarthritis cartilage injury.1)Morphological characteristics of rabbit knee osteoarthritis model at different stages of developmentObserve the imaging data of the rabbit knee osteoarthritis model at different stages of the disease course(1-3 months)under 9.4T MRI,and compare it with the gross specimens of the same period to evaluate the accuracy of MRI classification.And explore related sensitive indicators to provide a theoretical basis for the diagnosis of osteoarthritis under ultra-high field intensity magnetic resonance.The results indicate that the two diagnostic methods are highly consistent;Magnetic resonance has the advantage of quantitative assessment of cartilage tissue.Before the morphological changes of articular cartilage appear,magnetic resonance can measure related data changes,such as cartilage signal values,which can detect cartilage lesions early and improve the positive predictive value of graded diagnosis,and provide experimental basis for clinical promotion.2)Changes and signficance of blood routine,CRP and erythrocyte sedimentation rate in rabbit knee osteoarthritis modelPurpose and methods:The pathogenesis of osteoarthritis is relatively complicated,and most of them are the result of a series of internal and external factors.Clinical diagnosis is mostly based on imaging,but early patients are likely to miss the diagnosis.It is hoped that the detection rate can be improved by combining common clinical examination methods.Blood routine,CRP and erythrocyte sedimentation rate tests are the most widely used clinical blood test techniques,which can more accurately reflect the physiological activities and pathological changes of the body,and play an important role in the diagnosis and prognosis of the disease.This experiment intends to observe the above indicators in the changes in animal models of knee osteoarthritis in different periods provide a reference for the early diagnosis of osteoarthritis.The results indicate that NLR,PLR,ESR,and CRP were positively correlated with the grading of magnetic resonance cartilage damage;the LMR were negatively correlated,and differences are statistically significant(P<0.05).It shows that it is related to the severity of osteoarthritis,and it can be used to assist the MRI diagnosis of osteoarthritis.3)Expression of inflammatory factors/anti-inflammatory factors in peripheral blood and synovial fluid during the pathological changes of rabbit knee osteoarthritis modelThe pathological change basis of osteoarthritis involves the whole joints and surrounding auxiliary structures.As early as the initial stage of the disease,there are different degrees of inflammation.The anti-inflamatory anabolic process is driven by a variety of mediating factors,and its key role is attributed to the mutual influence of the cytokine network.The most important groups to regulate this disease mainly include inflammatory cytokines(such as IL-1?,TNF-?,IL-6,IL-15,IL-17A and IL-18,etc.)and anti-inflammatory cytokines with antagonistic effects(such as IL-4,IL-10 and IL-13,etc.).This experiment intends to observe the expression of inflammatory cytokines IL-1?,IL-6,IL-17,TNF-? and IL-10 in serum and knee joint fluid of rabbit models of knee osteoarthritis in different periods.Explore its early pathogenesis and provide reference for the early diagnosis of osteoarthritis.The results indicate that the expression of IL-1 ?,IL-6,IL-17 and TNF-? were positively correlated with magnetic resonance grading,and the differences were statistically significant(P<0.05).IL-10 was negatively correlated with MRI grade,but there was no statistically significant difference(P>0.05).4)Expression and significance of COL2,MMP3,MMP13 and TIMP-1 protein in cartilage tissue of knee jointMatrix metalloproteinases(MMPs)can degrade extracellular matrix type ?collagen(COL2)and chondrogenic glycans,while tissue inhibitor of metalloproteinase-1(TIMP-1)can inhibit its activity,so its expression imbalance plays a key role in the pathogenesis of osteoarthritis.This experiment intends to observe the expression of COL2,MMP3,MMP13 and TIMP-1 protein in the cartilage tissue of the knee osteoarthritis rabbit model at different stages to explore the mechanism of early knee osteoarthritis.The results indicate that the type ? collagen of each model was obviously lost,and the longer the model building time,the more the loss.Compared with the normal control group,the expression levels of MMP-3 and MMP-13 protein increased significantly with the prolongation of the modeling time.Although the level of TIMP-1 increased significantly,it was less than that of MMP.Tissue metabolism is still out of control.5)The diagnostic value of 3.0T MRI in the classification of knee osteoarthritis cartilage injuryAt present,most of the graded diagnosis of knee osteoarthritis is subjectively evaluated and lacks quantitative standards,which brings certain difficulties to the diagnosis.In order to solve this problem,this study chooses easily quantifiable indicators,such as cartilage thickness,cartilage volume,and signal value,analyzes their application value in the classification of cartilage damage by observing their change characteristics under MRI.The results indicate that the grading results of MRI for knee osteoarthritis cartilage damage are highly consistent with arthroscopy,and the accuracy rate is high.Referencing indicators such as cartilage thickness,cartilage volume and signal value in MRI classification can effectively improve the diagnosis rate,especially for early knee osteoarthritis,which provides an effective basis for clinical classification and prevention and is worthy of application and promotion.