| Objective:The aim of this study was to investigate apoptosis and pathological changes at early stage of rats supraspinatus tendinopathy with overuse. Methods:Forty adult Sprague-Dawley rats were randomly divided into eight groups,with 5 rats in each group. Seven exercise groups were subjected to an overuse protocol that consists of downhill running(10% grade) at 17m/min for 1h/day,5 days/week, for 1,2,3,4,5,6 weeks, another group rats underwent six weeks running and two weeks rest. Control group of rats served as nonrunning time 0 week. Paraffin sections were cut and stained with hematoxylin-eosin (HE) for routine histologic examination. Apoptosis was detected by terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL) method and Caspase 3 activaty assay in which the frequency of the apoptotic cells was expressed by the apoptotic index. Results:The supraspinatus tendons from 5 W,6 W,8 W exercise groups showed significant degeneration.The apoptotic indices were significantly higher in 5 W,6 W groups than in the OW control group. Conclusion:overuse seems cause supraspinatus tendon degeneration and apoptosis of the tendon cells. |
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