| Purposes: Exogenous PGE2 was originally used as a chemical inducer in animal model making of enthesiopathy, but with further studies, researchers have found that exogenous PGE2 also has the positive impact on repairing tendon. This study did an intervention on healthy male SD rats by using exogenous PGE2,to find out the Histological and biomechanical effects of different dose of exogenous PGE2 on the patellar tendon tissues.Methods: 1. 36 eight-month-old male SD rats were randomly divided into group 100 ng and group 800 ng. Then, the left leg of rats which belong to 100 ng group(18) were recorded as low dose group, 18 right legs were randomly divided into low dose of blank group(6), Low dose of acupuncture group(6), low dose of sodium chloride group(6). We did the same work for the group of 800 ng. 2. All rats were on normal chow feed. We keep different groups of rats on the corresponding test intervention treatment on first day, seventh day, fourteenth day, and twenty-first day on the test. 3. All rats were killed and to get samples on the twenty-eighth day after the test began. The samples were respectively used for transmission electron microscope, biomechanical testing, observation and determination of the related indexes of biomechanics and the pathology histology of patellar tendon of the rats.Finds:1. The appearance of patellar tendon tissue of the high dose of group, low dose of blank group, acupuncture group, and saline group was: white, elasticity and toughness, and shiny. Patellar tendon Intervention of the high and low dose of group showed different levels of vascularization, dark color, lack of toughness, softness, and adhesion occurred on tendon sheath.2. High, low dose of blank group, acupuncture group, saline group patellar tendon cell function has relatively developed and been comprehensive, the organelles were rich the cell proliferation active, but part of the cells were damaged. The low dose group of patellar tendon cells were low, the developed degree of the organelles of the cells decreased, and the damage was very serious. The high dose group of patellar tendon cell function is extremely underdeveloped, the extent of the damage was very serious, and the newborn collagen fiber was not observed.3. The width and thickness of lateral patellar tendon of the rats that had exogenous PGE2 in the intervention remained the same as the lateral patellar tendon( P>0.05), there was no significant difference in each group of bilateral patellar tendon width and thickness.4. The high and low dose group showed a high significant reduction compareed with thecontralateral blank group( P<0.01), acupuncture group( P<0.01), and the normal saline group( P<0.01). The high dose group’s decline was significantly higher than the low dose group in the maximum load, because the contralateral blank of the high dose, the contralateral acupuncture group of high dose, the physiological saline group of high dose comparing with the contralateral blank of the low dose, the contralateral acupuncture group of low dose, the physiological saline group of low dose, which showed minor difference( P<0.01). And there was no significant difference( P>0.05) in the maximum load.5. On the side of physiological saline group of high dose compared with the side of saline group of low dose, the result had significant difference( P<0.05), the physiological saline group of high dose decreased the tensile strength higher than the side of saline group of low dose. The other groups’ comparison results are consistent with the maximum load of the comparison results.Conclusion:1. Exogenous PGE2 caused histopathological changes of patellar tendon, and degenerative change of the organization, and induced tendonitis. The degenerative changes induced by 800 ng larger than 100 ng.2. Exogenous PGE2 significantly reduced the biomechanical properties of tendon tissue, and the reduction of biomechanical properties by 800 ng was larger than 100 ng. |
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