Experimental Study On The Influence Of Overuse Activity To The Supraspinatus Tendon In A Rabbit Model: A Histological And Ultrasonographic Study

Objective: To study the influence of overuse activity on the shoulder joint disease by morphology and ultrasonography of the supraspinatus tendon in rabbit models, so as to to investigate the etiology of the shoulder disease and provide a theory basis for prevention, diagnosis and therapy for the shoulder disease. Methods: Overuse animal model was established in New Zealand white rabbits. 24 rabbits was randomly divided into two groups ,and experienced 4 weeks and 8 weeks overuse united with bilateral shoulder joints, and then killed them to achieve the supraspinatus tendons.The tendon samples were studied by HE to investigate the changes of the histology. The tendon samples were studied by picrosirius-polarization method and were observed under the polarization microscope.. .Using image analysis system-to investigate the changes of the collagen and the quantitated changes of collagen type I and HI. To detect the morphological changes of overused rabbit supraspinatus tendons by ultrasonic apparatus in order to demonstrate the the relationship between the overusing and injury of supraspinatus tendons. Result:There had no obviously difference between the normal and the overused tendons to the naked eye. They appeared glistening white and had no adhesion with the surrounding tissues. Under microscopy, regular parallel bundles of collagen- 3 -fibres and spindle shaped tendon cells were found in the longitudinal section of the normal tendons. The components of collagen present predominantly with type I collagen. After overuse activity, the tendon lost their normal structure at the site where the tendon faced the shoulder joint and showed some structural features of fibrous cartilage. The ovoid chondrocyte-like cells and the fibrocartilage in the tendon were also found, The components of collagen present predominantly with type III collagen. After 8 weeks of overuse, The change become obvious.The ultrasonic echo of the normal tendons are even ,The ultrasonic echo of the overused tendons becomes poor-distributed and thin. Both of the weak and stong signals can be detected, but the graphs of the resonance cannot be seen obviously. Conclusion: There will have some effect on the histology of the supraspinatus tendons when shoulder joints have overuse activities. In order to adapt to the changeand, The parts facing the shoulder joint show some changes of fibrocartilage,so,The risk of the tendon injury become high.After the athletics, There are more typelllcollagen in the tendon and The ultrasonographic findings of the tendon is poor-distributed and thin.These researches show that overuse activity can increase the risk of trauma and inflammation of the supraspinatus tendons and is an important factor to shoulder joints diseases. These maybe provide some theory basis for prevention, diagnosis and therapy for the shoulder joint diseases.