Experimental Study On Animal Model Of Chondromalacia Patellae Guided By Balance Theory

Objective: To observe the effect of joint static and dynamic balance breaking through axial fatigue movement on patellofemoral articular cartilage in rabbits.The stable model of Chondromalacia Patellae(CP)was verified by pathological score,modified Lequesne MG score,MRI examination and concentration of related serum markers COMP and MMP-9.It provides a stable and reliable model basis for animal experimental study of patella softening.Research method: Firstly,15 mature month-old healthy and clean female New Zealand rabbits were divided into 3 groups according to the random number table method,including cycle group,frequency group and day length group,with 5 rabbits in each group.Three factors and five levels of screening experiment were conducted to build models.During the modeling,the experimental animals were supine and upward,except for the modeling limbs,the other parts were fixed on the rabbit plate with traction belt and adhesive tape,and the hind limbs were fixed on the movable plate of the modeling machine with tie belt,forcing the New Zealand rabbit knee joint to passively flex and extend continuously.The activity parameters of experimental animals were set according to the selected activity factor level.After modeling,the animals were screened for two levels according to modified Lequesne MG score,pathological score,serum COMP concentration and serum MMP-9concentration.Then,according to the screening results,an orthogonal experiment with three factors and two levels considering the interaction was conducted.Sixteen mature female New Zealand rabbits were selected and divided into 8 groups according to the random number table method,with 2 rabbits in each group,for anteraxial fatigue movement of bilateral patella.The optimal combination of factor levels was selected according to modified Lequesne MG score,pathological score,serum COMP concentration and serum MMP-9 concentration.At last,a large number of models were made according to the factor level setting of the optimal combination.Twenty-four mature,healthy,clean female New Zealand rabbits were randomly divided into model group and blank group according to the random number table method.After adaptive feeding,animals in the model group were modeled by axial fatigue movement.Finally,modified Lequesne MG score,Mankin pathological score,NUCLEAR magnetic resonance examination,serum COMP concentration and serum MMP-9 concentration were used to judge the success rate of modeling,and the score difference between blank group and model group was compared to determine whether the joint static and dynamic equilibrium was broken by axial fatigue movement.Whether a stable and reliable animal model of patelomalacia can be constructed.Research result:1 In the three-factor and five-level screening experiment,according to the knee joint grade assessment score of modified Lequesne MG,Mankin’s score,serum COMP content and serum MMP-9 content observed under pathological staining and light microscope,the screening levels of the periodic group were 14 days and 19 days.The screening levels of frequency group were 40 times /min and 60 times /min.The screening results of day length group were 90min/ day and 120min/ day.2 In the orthogonal test with three factors and two levels considering interaction,according to the knee joint grade assessment score of modified Lequesne MG,Mankin’s score,serum COMP content and serum mmp-9 content observed under pathological staining and light microscope,the period of 19 days,the frequency of 60 times /min,and the activity time of 120 min per day,The range of motion of joints,pathological changes of cartilage,content of COMP and m MP-9 in serum were significantly higher than those of other factors.3 In the experiment to verify the success rate of modeling,the knee joint grade evaluation score of the modified Lequesne MG,Mankin’s score observed under pathological staining and light microscope,serum COMP content and serum MMP-9content of the model group were significantly higher than those of the blank group,with statistically significant differences(P > 0.05).On MRI,the patella cartilage and even the femoral patellar surface cartilage were obviously damaged in the model group,while the blank group showed uniform gray bands and no cartilage damage was observed.Research conclusions:1 The influence of the three factors of anteriaxial fatigue on articular cartilage lesions does not necessarily increase with the increase of the level.2 The horizontal screening experiment was conducted based on exercise period =14days,activity frequency =60 times /min,and activity duration =90min/ day.The screening results were exercise period: 14 days,19 days;Activity frequency: 60 times/min,80 times /min;Activity duration: 90min/ day,120min/ day.3 In the orthogonal test considering interaction,the activity period =19 days,activity frequency =60 times /min,and activity duration =120min/ day were the combination of factors that caused the most serious damage of patellofemoral articular cartilage by breaking the balance of joint motion.