Overuse Could Induce Rats Patellar Tendon Injury And Apoptosis Of Tenocyte

Objective:To study the influence of patellar tendon cellls and collagen fibers after overuse. Methods:Forty SD rats were divided into eight groups at radon,including thirty five cases in experimental group and five cases in control group.Five rats patellar tendons were cut for specimens every week after overuse in experimental group.The presence of apoptosis was examined with immunohistochemical methods using a polyclonal antibody recognizing active Caspase-3 and the TUNEL assay.At the meantime,we stained sections with hematoxylin to observe tissues morphous. Results:The TUNEL assay showed that,the apoptotic cells of specimens after four,five and six weeks overuse,were significantly more than those in the control(P<0.05).The apoptotic cells of specimens after sis weeks overuse were more than those after four and five weeks (P<0.05).The changes in active Caspase-3 was similar to that of the TUNEL assay.Hematoxylin and Eosin stain showed that,after one to three weeks, patellar tendon cellls and collagen fibers had no evident change.After four and five weeks, more patellar tendon cellls were seen.After sis weeks,the array of collagen fibers was disorganized.Afte two weeks rest,the apoptotic cells decreased largely. Conclusion:The apoptotic cells of patellar tendon araised after four and five weeks overse,and patellar tendon cells proliferated.After sis weeks,there were more apoptotic cells,and the array of collagen fibers was disorganized.Afte two weeks rest,the apoptotic cells of patellar tendon decreased largely,but the array of collagen fibers was disorganized too.