The Change Of Articular Cartilage After Blunt Injury

【Objective】To observe the ultructure of articular cartilage and change of typeⅡcollogen after blunt injury, to investgate the etiopathogenesis of traumatic osteoarthritis.[Materials and methods] The different cartilage injury models of the femoral trochlea of rabbit in vivo was made by impacting of different times.24 New Zealand adult rabbits were divided randomly into 20 times and 40 times groups,each group was 12. One side was experimental groups, the opposite side was control group. Four rabbits were killed at each of the following intervals:1 week,4 weeks,8 weeks after impacting injury. The specimens were observed as pathology histological sections and strained by HE,safranin O. The sections were strained by typeⅡcollogen monoclonal antibody immunohistochemistry and in situ hybridization of mRNA of typeⅡcollogen. The ultrastructures of the cartilage were observed by transmission electron microscope(TEM). The values of gray scale were obtained by imaging analysis.【Results】(1) The pathological changes of articular cartilage of experimental group(EG) were more severity with time.(2) Chondrocyte in experimental group was occurrent a series of changes:karyopycnosis,karyolysis,rough endoplasmic reticulum (RER) broaden,mitochondrion swelling,lysosome appear,cell membrane rupture, and so on. On the whole, changes appear with the pathological changes of articular cartilage.(3) Immunohistochemistry and in situ hybridization of mRNA of typeⅡcollogen indicate:in early stage of post-injury,secrete and expression of typeⅡcollogen was increased to the level of control group. secrete and expression of typeⅡcollogen was decreased to the level of control group with pathological changes of articular cartilage was severity.(4) There is significantly different from between the 20 times group and the 40 times group.【Conclusion】(1) Impact lead to cvartilage maxtrix injury and chondrocyte death,pathological changes of articular cartilage were severity with time lasting.(2) pathological changes of articular cartilage were severity with impact times increase.(3) Stop impact, pathological changes of articular cartilage were development.