Effect of therapeutic knee-pads for arthritis on transforming growth factor-beta and insulin-like growth factors in joint fluid of rabbits with knee osteoarthritis

Objective:To observe the effect of therapeutic knee-pads for arthritis on transforming growth factor-beta(TGF-β)and insulin-like growth factors(IGF)in joint fluid of rabbits with knee osteoarthritis(KOA),and to explore the possible mechanism of therapeutic knee-pads for arthritis in the treatment of KOA.Methods:Fifty-four Japanese white rabbits were randomly divided into 6 groups,10 cases in normal group,9 cases in model group,9 cases in control group,9 cases in experimental group 1,8 cases in experimental group 2 and 9 cases in experimental group 3.The rabbits were operated on the right knee-joint to build models of knee osteoarthritis using the modified Hulth method in model group,control group,experimental group 1,experimental group 2 and experimental group 3.After modeling,rabbits in normal group and model group were administrated with conventional feeding without intervention;rabbits in control group were administrated with microwave apparatus treatment;rabbits in experimental group 1 were administrated with therapeutic knee-pads for arthritis in the-mode of density wave;rabbits in experimental group 2 were administrated with therapeutic knee-pads for arthritis in the mode of thermotherapy;rabbits in experimental group 3 were administrated with therapeutic knee-pads for arthritis in the mode of density wave and thermotherapy.The macrostructure of knee joints of the rabbits in the 6 groups were observed through the X-ray pictures of their both knees photographed in the anteroposterior position at the 16th week after modeling.Meanwhile,the contents of TGF-β and IGF in the fluid of modeling joints were measured through radioimmunoassay.Results:①X-ray picture:Such situations as normal medial and lateral knee joint gap,smooth joint surface,intact regular edges of joint and uniform subchondral bone were found in normal group.Obvious narrow medial knee joint gap,deformed surface of joint,phanic osteophyma on the edge of joint and obviously increased density of subchondral bone were found in model group.The changes of knee joint of patients in control group lay somewhere between those of experimental group 1 and experimental group 3.The changes of knee joint of patients in experimental group 1 were same as those of model group basically.The changes of knee joint of patients in experimental group 2 lay somewhere between those of experimental group 1 and experimental group 3.Narrow medial knee joint gap,deformed surface of joint,unconspicuous osteophyma on the edge of the joint and increased density of subchondral bone were found in experimental group 3.②TGF-beta content:There was statistical difference in TGF-beta contents among the 6 groups(F=23.757,P=0.000).TGF-beta contents of normal group were lower than those of model group,control group,experimental group 1,experimental group 2 and experimental group 3 respectively(P=0.000,P=0.000,P=0.000,P=0.000,P=0.000).TGF-beta contents of model group were lower than those of control group,experimental group 2 and experimental group 3 respectively(P=0.000,P=0.000,P=0.000).TGF-beta contents of experimental group 1 were lower than those of control group,experimental group 2 and experimental group 3 respectively(P=0.028,P=0.007,P=0.002).There was no statistical difference between any other couple groups.③IGF content:there was statistical difference in IGF contents among the 6 groups(F=9.074,P=0.000).TGF-beta contents of normal group were lower than those of model group,control group,experimental group 1,experimental group 2 and experimental group 3 respectively(P=0.040,P=0.000,P=0.027,P=0.000,P=0.000).TGF-beta contents of model group were lower than those of control group,experimental group 2 and experimental group 3 respectively(P=0.012,P=0.004,P=0.000).TGF-beta contents of experimental group 1 were lower than those of control group,experimental group 2 and experimental group 3 respectively(P=0.026,P=0.010,P=0.001).There was no statistical difference between any other couple groups.Conclusion:The mechanism of therapeutic knee-pads for arthritis in the treatment of KOA maybe rely on the raise of expression levels of TGF-β and IGF in articular synovium and articular cartilage,and on the promotion of cartilage cells proliferation and differentiation and synthesis of extracellular matrix as well on the restraination of inflammatory reaction in the synovium on the purpose of slowing down the regression of articular cartilage and improving its repair.