| Purpose:The injury of bone-tendon junction has a close relationship with the local stress. Bone structure from the bone-tendon junction will affect formation and healing precess of the injury. At the base of establishing a model of making bone-tendon junction to be in juried with cyclic loading, this study compares the impacts of two different ways to bone-tendon junction injury, rest and low intensity cyclic loading. Micro-CT is used to assess the bone structure from bone-tendon junction of the two methods. The result will show which recovery method is more rational for bone-tendon junction after chronic injury.Method:19matual famele New Zealand rabbits (18weeks, weight2400±200g) were randomly divided into control croup(n=10), rest recovery group(RR, n=7),low intensity cyclic loading group(LL, n=7). Animals from two experimental groups receiveing unified cyclic loading stimulation with30%max muscle contraction in first4weeks. The loading intensity is7.06±0.71(N),2hours per time,3times a week, total4weeks. After that, Rest recovery group stopped and change cyclic load to4.2N/S for low intensity cyclic loading group, experimental time is similar with before. Tissues were drawed at8weeks. Firstly, proceeding Micro-CT scan reconstruction and followed by H&E stained tissue section. The result of Micro-CT is used to evaluate the micro-structure of bone trabecula and observing hyphology change of bone-tendon junction with H&E section.Result:Histological observation shows that compared with CON group, there are disordered arrangement of tendon cells, cells aggregation, hyaline and tide line becomes unclear or disappeared in LL group and RR group. In the zone uncluded bone, the value of TV、BV、BS、BS/BV、BS/TV from CON group, LL group and RR group has no significant difference. BV/TV has significant difference between RR group and CON group. In bone zone, the value of TV、BV、BS、BS/BV、BS/TV from CON group、LL group and RR group has no significant difference. BV/TV of RR group decreased significantly comparing with CON group (P<0.05).Tb. Th has significant difference between LL group and CON group (P<0.05). The difference of Tb. Pf between LL group and CON group is very significant (P<0.01). Tb.N、Tb.Th and Tb. Pf from RR group also have very significant difference comparing with CON group (P<0.01)Conclusion:1.4weeks low intensity cyclic loading have no significant effect on bone volume of tendon insertion.2.4weeks low intensity cyclic loading after injury can promote the process of bone microstructure remodeling and adapting which from tendon insertion. |
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