Effect Of Intra-articular Injection With Doxycycline In The Treatment Of Rabbit Knee Osteoarthritis Model By Plaster Immobilization

Purpose:To investigate the effect of intra-articular injection with doxycycline in the treatment of rabbit knee osteoarthritis model by plaster immobilizationMethods:The 48 white rabbits were devided into 2 groups as random,42 experimental,6 normal control.The experimental animals with left knee immobilized in extension position sacrificed after four weeks,6 (group with left knee immobilized four weeks) were harvested to observe the macroscopic changes of femoral condylar cartilage and pathological changes of cartilage,and confirm the OA model succeed.the other 36 were randomly devided into treatment group, negative control group, model control group,the treatment group were intraarticularly injected 1.33% doxycycline 0.3ml once a day, negative control group were intraarticularly injected physlologic saline 0.3ml once a day, model control group were not injected and all rabbits sacrificed after 4 weeks and 8 weeks,Then the degeneration of articular cartilage, Mankin score, the release of nitricoxide(NO)and the activity of total nitricoxide synthase(NOS) of the joint fluid,MMP-3,uPA experssion and synovial membrane IL-1 experssion..Results:1.compare with the normal control group, the colour of cartilage of group with left knee immobilized four weeks became dark., Mankin score high (P<0.05), high of experssion uPA,MMPs-3 and synovial membrane IL-1 (P<0.05), high concentration NO release and high activity of NOS in the joint fluid (P<0.05)2.compare with the group with left knee immobilized four weeks,the model control group Mankin score high (P<0.05), high of experssion uPA,MMPs-3 and synovial membrane IL-1 (P<0.05), high concentration NO release and high activity of NOS in the joint fluid (P<0.05)3.compare with the model control group, the cartilage of the negative control group Mankin score high (P <0.05), high of experssion uPA,MMPs-3 and synovial membrane IL-1(P<0.05), high concentration NO release and high activity of NOS in the joint fluid (P<0.05),but after 8 weeks,the two groups donot have difference4.compare with the model control group and the negative control group,the cartilage of treatment group is smooth, Mankin score Low (P<0.05), low activities of uPA,MMPs-13 and synovial membrane IL-1 (P<0.05), low concentration NO release and low activity of NOS in the joint fluid (P <0.05)Conclusion: 1.after animal left knee immobilized in extension position 4 weeks,we can obtain satisfactory OA model2.Intraarticularly injection with doxycycline could prevent the worsening of OA models by inhibiting the experssion uPA,MMPs-3 and synovial membrane IL-1, inhibiting the production of NO and activity of iNOS in the joint fluid.