The Repairing Effect To Condylar Cartilage Of Temporomandibular Joint Osteoarthrosis With Sodium Hyaluronate In An Animal Study

PurposeInjection with sodium hyaluronate into the temporomandibular joint articular cavity is clinically common minimally invasive treatment in the temporomandibular joint osteoarthrosis(TMJOA), the dog is the research object, the dog TMJOA model was successfully built by one-time articular cavity injection with collagenase, then condylar cartilage histopathologic change was observed after the sodium hyaluronate articular cavity injections treatment, further treatment function with hyaluronic acid sodium in TMJOA was discussed, this will provide the basis in the clinical research.Methods6mongrel dogs were adulthood, weight of15-18kg, no obvious mouth jaws system diseases, every dog was injected with1%collagenase lml (400U/mg) into the left side of the temporomandibular joint cavity after onset of anesthesia. After the injection in1,2,3,4,5, and6weeks, every dog was put into death, the complete joints were taken out and fixed in10%neutral formalin for24hours.Then Specimens were put into10%EDTA decalcification for2weeks (replaced once every two days decalcification solution).Unitil a pin that can easily pierce it. Fixed, decalcified, embedded tissue sections, stained with HE and Safranin O, investigate histilogical changes of condylar cartilage, so as to construct the TMJOA model. the bilateral TMJOA model were constructed in the other6same specifications dogsl, in1,2,3weeks after the construction, medical sodium hyaluronate0.5ml (10mg/ml, molecular weight:84000) were injected into the left TMJ cavity, the right TMJ were injected with saline0.5ml as control. After dogs were raised for four weeks.then were put into death and bilateral TMJ materials were decalcified, embedded tissue sections, stained with HE and Safranin O, investigate histilogical changes of condylar cartilage.ResultsThe collagen fiber hydrolysis in the surface, the loss of the proteoglycan, the coarse cartilage surface and gradually appearing of articular cartilage peeling, crumbling, formation of cartilage fissure, the exposed bone, rough texture, even bone hyperplasia and osteophyte were observed in1,2,3,4,5, and6weeks after the injection of collagen enzyme in6dogs of Animal model group, so as TMJOA dog model were successfully established.The other6dogs in the treatment group after establishing bilateral TMJOA were treated with sodium hyaluronate for3weeks, we found that articular damage in the sodium hyaluronate side is light, because the cartilage has a clear hierarchy, pathological changes just limited to surface; While damage in the Physiological saline side articular is serious, such as coarse cartilage surface, disordered fiber cartilage, the interruption of fibrocartilage continuity were observed, some area appeared that the fibrocartilage was fallen off, and replaced by fibrous tissue, some specimen even appeared the bone fracture and osteophyte. Histologic evaluation scores were get according to the improved system Mankin to joint osteoarthrosis, the SPSS19.0statistical software was used for the data analysis. The score of Sodium hyaluronate side:3.17±0.75for (n=6), The score of physiological saline side:7.83±1.67(n=6). there was significant differences on both sides by the t test in the independent sample data (P<0.01). The contrast of Safranin O dyeing shows, lateral cartilage in sodium hyaluronates side was dyed more uniform and the color is more deep, while some area of the other side was not dyed in the articular cartilage matrix.Conclusions1. Dog TMJOA model can be successfully established through the one-time injection with collagen enzyme into TMJ articular cavity, pathological changes underwent the collagen fiber hydrolysis in the surface, the coarse cartilage surface, and gradually appearing of articular cartilage peeling, crumbling, formation of cartilage fissure, the exposed bone, rough texture, even bone hyperplasia and osteophyte. The whole process accompanied with the loss of the proteoglycan in the cartilage matrix. Above the pathological changes of the process TMJOA model are in agreement with the changes in other TMJOA animal model and the change in human TMJOA by endoscope and hyphology methods. 2. Exogenous sodium hyaluronate injection can promote condylar cartilage to repair in dog TMJOA and maintain the normal layer of cartilage, the specific mechanism may avoid the proteoglycan continueing to erosion and hinder the progress of the TMJOA further.by promoting proteoglycan to gather together.