Study On The Mechanism Of Knee Osteoarthritis Based On Proprioceptive Disorders

1 ObjectiveTo investigate the effects of unilateral L3/L4 spinal dorsal root rhizotomy on the ipsilateral lower limb motor function,articular cartilage and ligamentous receptors in the ligament,and to further verify that the partial sensory disturbance can cause degeneration of articular cartilage.2 MethodsThis study choose 70 healthy SD rats were randomly divided into 3 groups(weight 300-450g):the normal control group(10),the proprioception disorders group(30)and the classic model group(30).Group:(1)The normal control group,natural growth.(2)The proprioception disorders group,the right side of dorsal rhizotomy:select 10%Chloral Hydrate with celiac anaesthesia,then the prone position,with a rubber band is fixed in the rat limbs and L1-L5 centrums were counted,along the midline to the right as the center is about 8cm long incision,under a microscope in addition to bite on the right side of the corresponding part of the laminar and articuli intervertebrales,exposed on the right side of L3/L4 dorsal roots.After posterior rhizotomy layered suture wounds.(3)The classic model group,the modified Hulth model method:cut the right side of the lower limb skin and subcutaneous tissue,The medial collateral ligament and anterior cruciate ligament of SD rats were cut off,and the medial meniscus was completely separated.All rats were forced to walk training for 30 minutes every day after the operation.the sensory evoked potentials(SEP)and electromyogram(EMG)of the rats were measured by BL-420S system respectively at 2/6/10 weeks after operation,and he behavior and muscle strength of the rats were evaluated by modified Tarlov Grading method to assess.After the measurement,the right anterior cruciate ligament was taken out and stained with gold chloride and the articular cartilage of the knee was made into paraffin sections for HE staining.The morphological function of the proprioceptor structure in the ligament was observed under light microscope,and the proximal tibial of Cartilage and sub-chondral bone morphological changes of expression,compared the difference between the three groups.3 Results(1)The changes of the rats motor state:There were no the symptom of dyskinesia in all rats before the scoring,and the wound healed well without any signs of infection.In the classical model group,the motor function of the right hind limb was dyskinesia in different degree at 1 week after operation,according to the modified Tarlov method of hind-limb muscle strength score was lower than that of the proprioception disorders group.At 2 and 6 weeks,the two groups have no statistically significant difference.(2)The changes of the rat's cortex sensory evoked potential(CSEP):In the proprioception disorders group,the latency of SEP was prolonged and the amplitude was decreased in 2 to 6 weeks,and there was significant difference by group comparison(P<0.05).In 2weeks,there was no significant difference in latency and amplitude between the classic model group and the normal control group(P>0.05).There was significant difference by group comparison at 6-10 weeks(P<0.05).(3)The changes of the rat's electromyogram:In the classic model group,the latency of electromyogram was prolonged and the amplitude was decreased in 2 to 6 weeks,and there was significant difference by group comparison(P<0.05).In 2weeks,there was no significant difference in latency and amplitude between the classic model group and the normal control group(P>0.05).There was significant difference by group comparison at 6-10 weeks(P<0.05).In 2weeks,there was no significant difference in latency and amplitude between the proprioception disorders group and the normal control group(P>0.05).With the extension of the time,there was significant difference by group comparison(P<0.05).(4)The changes of cartilage histological observation and modified Mankin score:At 2 weeks,the four-layer structure of the articular cartilage of the tibial superior articular cartilage was complete and the number of chondrocytes was normal.The modified Mankin score of the two groups was higher than the normal group,the difference was statistically significance.At 6 weeks,the superficial layer of the articular cartilage was found to damaged in the proprioceptive disorder group,while in the classical model group,the cartilage mast cell layer was damaged in some regions,and the number of cells decreased.At this time,the two groups of the modified Mankin score difference was statistically significant(P<0.01).At 10 weeks,the four-layer structure of the articular cartilage in the classical model group was damaged and the number of chondrocytes decreased.In the proprioceptive disorder group,the articular cartilage was injured to the middle layer and the number of cells increased.At this time,the two groups of Mankin score difference was statistically significant(P<0.01).Meanwhile,except for the normal control group at different time points,there was significant difference between the two groups(P<0.01).(5)The changes of the Gold chloride staining:In the proprioceptive group,in the anterior cruciate ligament the number of proprioceptors decreased gradually in 2 weeks,6 weeks and 10 weeks,and the bulk receptor decreased,and some structural defects appeared in the proprioceptors(P<0.05),compared with the classical model group and the normal control group,there was significant difference(P<0.05).In the classical model group,there was significant difference(P<0.05)in comparison with the normal control group because of the cut off of the anterior cruciate ligament.4 Conclusion(1)The joint function of knee osteoarthritis is affected by the muscle strength and proprioception function of mutual infulence around the joint knee osteoarthritis may result in the loss of proprioception.(2)The proprioception of the knee joint can lead to the change of the articular artilage and sub-chondral bone,which can lead to the generation of knee osteoarthritis.(3)The loss of proprioception of the knee joint is an important factor to promote the occurrence and development of knee osteoarthritis,but further experimental research is needed.