Overuse Could Induce Rat Long Head Of Biceps Tendon Injury And Apoptosis Of Tenocyte

Objective:To investigate the influence of overuse for the rat long head of biceps tendon and the apoptosis of tenocyte. Method:the 40 Sprague-Dawley (SD) rats were randomly divided into 8 groups,1 control group, and the remaining 7 groups as the experimental group, experimental group 17m/s downhill (10°) running, each 1 hour days, five days a week to establish excessive movement model. The tendons of control group were harvested Ow, the tendons of running groups were harvested 1 w,2w,3w,4w,5w and 6w after running, group 7 after rest 2w, The tendons were harvested at 8w. With hematoxylin to observe the changes of the organizational.The apoptosis of the tenocyte were quantified with the Caspase-3(Cysteine containing aspartate specific proteases-3) and TUNEL assay. Results:(1)Hematoxylin and Eosin stain Form 1 to 4 weeks the chang of collagen fibers were a gradual process.While the control group havinng no irregular of the collagen fibers. After 4 weeks'overuse, the change of long head of biceps tendon's was significent. The arrangement of the collagen fibers was irregular, some tendons colloge were degenerated Form 5 to 8 weeks the histological changes of recovery trend, at 8 week basic full repair of the tendon fibers. (2)The TUNEL assay showed that, the apoptotic of tenocytr of specimens after four weeks'overuse, were significantly more than those in the control(P<0.05).8w apoptosis index basically the same as the control group. (3)The changes in active caspase-3 was similar to that of the TUNEL assay. Conclusion:Overuse could induce rat long head of biceps tendon degeneration and apoptosis of tenocyte.