The Influence On Cartilage Repair Of Joint Distraction Height And Distraction Time In Rabbit Knee Osteoarthritis Models

Objective:To observe the influence on cartilage repair of joint distraction height and distrac--tion time in Rabbit Knee osteoarthritis Models.Methods:1.50 New Zealand white rabbits(male and female),5-6 months old,were randomized into two groups(the model group 43 rabbits,blank control group(group A)7rabbits).A model of rabbit knee osteoarthritis was made using joint injection of 4%papain hydrolytic saline solution.The blank control group was injected with saline.After6 weeks,1 rabbit of each group(the model group and blank control group)was sacrificed to prove the success of model at random.2.Then,42 rabbits of the model group were randomized into four groups: model control group(6 rabbits,group B),distraction height group(18 rabbits),distraction time group(18 rabbits).The distraction height group including normal Joint Space Width(JSW)group(6 rabbits,group C),1.5×JSW group(6rabbits,group D)and 2.0 ×JSW group(6 rabbits,group E).The distraction height group including 6 weeks group(6 rabbits),8 weeks group(6 rabbits),10 weeks group(6 rabbits).3.After prove the success of model.In distraction height group and distraction time group,joint distraction was carried out by the operation of Ilizarov External Fixator(3/4).Group A and group B did not do special treatment.At six weeks after joint distraction,animals of group A,group B and distraction height group were sacrificed for gross observation and macroscopically analyzed using ICRS system,HE staining,safranin O staining histologically analyzed using Mankin scoring system,and immunohistochemicalstaining of IL-1?,MMP-13,in order to observe cartilage repair.At 6,8,10 weeks after surgery,animals of distraction time group were sacrificed for gross observation and macroscopically analyzed using ICRS system,HE staining,safranin O staining histologically analyzed using Mankin scoring system,and immunohistochemical staining of IL-1?,MMP-13,in order to observe cartilage repair.4.The effects of distraction height on cartilage repair were obtained by analyzing the experimental results of group A,group B,group C,group D and E.The effects of distraction time on cartilage repair were obtained by analyzing the experimental results of group A,6 weeks group,8 weeks group and 10 weeks group.Results:1.The Effects of different distraction height on the repair of articular cartilage:(1)The articular cartilage of the group A was smooth and intact.In the group B,the defect of articular cartilage was obvious.The defect area of the group C showed regeneration of cartilage,only the defect area wasn,t complete filling.The constituent of regeneration was mainly filled with fibrous tissue and chondrocytes that only can be seen in the deep.In group D,the regenerated cartilage was completely filled the defect area and higher than the nomal organization.Histological observation was transparent cartilage,and multiple homologous cell groups were observed.The regenerated cartilage of group E was completely filled in defect area,histological observation was transparent cartilage,and all layers of cells were disordered.The ICRS score and Mankin score of C,D,E group was statistically significant compared with group B(P<0.001),in which D,E group was statistically significant compared with group C(P<0.001).There was no significant differences between group D,E(P>0.05).Group C,D,E was statistical significance compared with group A(P<0.01).(2)The cumulative optical density value of IL-1? and MMP-13 in cartilage tissue was analyzed by Image Pro Plus 6.0.The cumulative optical density value of group C,D,E was lower than that in group B(P<0.001),in which group C was higher than group D,E(P<0.001).There was no significant differences betweengroup D,E(P>0.05).The cumulative optical density value of group C,D,E was higher than that of group A(P<0.001).2.The Effects of different distraction time on the repair of articular cartilage: The articular cartilage of the group A was smooth and intact.The defect area of the 6 weeks group showed regeneration of cartilage.The regenerated cartilage was soft and cartilage surface could visible crack.Histological observation of shallow layer was filled with fibrous tissue.And the deep of the cartilage was filled with disordered chondrocyte.In the 8 weeks group,cartilage regeneration was observed in the defect area,the cartilage surface was not smooth,and the histological observation showed that the deep chondrocytes were in irregular arrangement.In 10 weeks,cartilage regeneration was observed in the defect area,and histological observation showed the rules of deep chondrocyte arrangement.(1)The ICRS score of 6 weeks group,8 weeks group,10 weeks group showed a trend of increase with the extended of distraction time,But there was no statistically significant difference(P>0.05).The ICRS score of 6 weeks group,8 weeks group,10 weeks group was statistically significant compared with group A(P<0.001).(2)The Mankin score of 6 weeks group,8 weeks group,10 weeks group showed a trend of decrease with the extended of distraction time,But there was no statistically significant difference(P>0.05).The Mankin score of 6 weeks group,8 weeks group,10 weeks group was statistically significant compared with group A(P<0.001).(3)The cumulative optical density value of IL-1? and MMP-13 in cartilage tissue was analyzed by Image Pro Plus 6.0.The cumulative optical density value of 6 weeks group,8 weeks group and 10 weeks group showed a trend of decrease with the extended of distraction time,But there was no statistically significant difference(P>0.05).The three experimental cumulative optical density value were higher than in group A(P<0.001).Conclusion:1.Distraction height:The results showed that the regeneration of cartilage could be better achieved by 1.5×JSW and 2.0×JSW group than the normal JSW group.2.Distraction time: In the joint traction of rabbit knee osteoarthritis.If the joint distraction height is 1.0*JSW,the cartilage repair of 6 weeks group,8 weeks group,10 weeks group showed a trend of improve with the extended of distraction time,But there was no statistically significant difference.