| Objectives To establish a rat model of distraction osteogenesis with femoral medullary cavity occlusion,and to study the effect of femoral medullary cavity occlusion on distraction osteogenesis,so as to provide experimental basis for clinical application of Ilizarov technique.Methods 56 male Sprague-Dawley rats were randomly divided into 4 groups,14 rats in each group,all underwent lateral extraperiosteal osteotomy of the left middle femur,and then installed an external fixation extender.After 7 days latency,it was extended at a rate of0.5 mm/d.Two times in the morning and evening,each time 0.25 mm,a total of 10 days,the left femur was extended by 5mm,and then entered the consolidation period.Group A: Only the left femur is stretched into bone.Group B: The right soleus tendon is taken,and the left femur is stretched into bone.Group C: the right soleus tendon was taken,the left femur was stretched into bone,and the soleus tendon sealed the proximall medullary cavity.Group D:the right soleus tendon was taken,the left femur was stretched into bone,and the soleus tendon sealed the bilateral medullary cavity.After entering the mineralization: 1 X-ray examination every 2 weeks to evaluate the mineralization of the distraction gap;2 At the end of 4 weeks and 8 weeks,3 rats in each group were sacrificed and the left femoral distraction gap was taken for histological HE Staining,observe the histological characteristics of the distraction gap,evaluate the mineralization;at the end of 8 weeks,observe the closure of the proximal and distal medullary cavity of the osteotomy line,and evaluate the effect of the soleus tendon closure;3 At the end of 4 weeks and 8 weeks,each group was sacrificed 4 rats,the left femoral distraction gap of the rat was examined by Micro-CT,and the bone volume(BV),bone volume fraction(BV/TV),bone surface area ratio(BS/BV),bone mineral density(BMD),etc.were quantitatively analyzed.Data to evaluate the mineralization of the distraction gap in each group.Results 1 X-ray: 2 weeks of consolidation,there are small amount of consolidation in the group A and group B of extended regions;group C and group D is extremely small in the two sets of distraction gap.At 4 weeks in the consolidation,some mineralization shadows were produced in two groups of distraction gap;the group C prolongs small amount of mineralization in the region;a small amount of mineralization in the nearest interceptor in the group D extension is produced,but the middle of the distraction gap no mineralization.At 6 weeks during the consolidation: group A and group B can be seen in the two groups of extensions;a large amount of mineralization is seen in the group C extension of the mineralization in the region;some of the near-section of the nearest interceptor end of the group D has some mineralization,distraction gap there is less mineralization.At 8 weeks of consolidation,the two groups of extensions are full of mineralization.There is no significant difference in normal bone tissue,and the extension of the region is well plastic;a large amount of mineralization in the group C extension,the bone density is higher than normal bone tissue low;group D extended a large amount of mineralization in the nearest interceptor end,the bone density is low,and the intermediate belt of the distraction gap is still visible to the obvious fracture line.2 Histological examination: 4 weeks in the consolidation,group B can be seen in the group B extended in the group,and the fiber tissue is visible;the C group extension of the abdomen chondrocytes is less but more fiber tissue;group D distraction gap a large amount of fiber tissue,but the cartilage cells are least.The blocked section is filled with fiber tissue,no tendon shrinkage,denaturation,and intramedullary blockage.At 8weeks in the consolidation,group A and group B,trabecular bone was obvious in the extension area,arranged along the approximate extension direction,and the medullary cavity was partially recanalized,which was filled with bone marrow;group C,there was a large amount of cartilage tissue and a small amount of bone tissue,but no obvious trabecular bone and no medullary cavity recanalization;group D,there was a large amount of fibrous tissue and no obvious bone like tissue.3 Micro-CT examination: 4 weeks in the consolidation:there is no difference in BV,BV/TV,BS/BV,BMD between group A and group B(P>0.05);there is no difference in BV between group B,group C and group D(P>0.05);there is significant difference in BV/TV between group B,group C and group D(P<0.05),and group B>group C>group D;there is no difference in BS/BV between group B and group C(P>0.05);there is significant difference in BS/BV between group B and group D(P<0.05),and group D>group B;there is significant difference in BS/BV between group C and group D(P<0.05),and group D>group C;there is no difference in BMD between group B,group C and group D(P>0.05).8 weeks in the consolidation: there is no difference in BV,BV/TV,BS/BV,BMD between group A and group B(P>0.05);there is no difference in BV between group B,group C and group D(P>0.05);there is no difference in BV/TV between group B and group C(P>0.05);there is significant difference in BV/TV between group B and group D(P<0.05),and group B>group D.there is significant difference in BV/TV between group C and group D(P<0.05),and group C>group D.there is no difference in BS/BV between group B and group C(P>0.05);there is significant difference in BS/BV between group B and group D(P<0.05),and group D>group B.there is no difference in BS/BV between group C and group D(P>0.05);there is no difference in BMD between group B and group C(P>0.05);there is significant difference in BMD between group B and group D(P<0.05),and group B>group D.there is significant difference in BMD between group C and group D(P<0.05),and group C>group D.Conclusions 1.A new distraction osteogenesis model was established by sealing the femoral bone marrow cavity of rats with soleus tendon.2.Remove the soleus tendon has no effect on the healing process of distraction osteogenesis.3.Sealing the proximal medullary cavity has no significant effect on the healing process of distraction osteogenesis.4.Sealing bilateral medullary cavity can delay the healing process of distraction osteogenesis,it is proved that bone marrow can promote distraction osteogenesis.Figure 19;Table 12;Reference 119. |
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