先天性胫骨假关节病变骨膜对大鼠胫骨发育的影响

Implication of pathological periosteum derived from congenital pseudarthrosis of the tibia in rat tibial development

目的探讨先天性胫骨假关节(congenital pseudarthrosis of the tibia,CPT)患儿病变骨膜对大鼠胫骨发育的影响,为CPT动物模型的建立提供理论基础。方法收集2021年4月至2021年5月在湖南省儿童医院骨科行手术治疗的CPT患儿胫骨病变骨膜和脑瘫患儿胫骨骨膜,分别将CPT患儿胫骨病变骨膜(实验组)与脑瘫患儿胫骨骨膜(对照组)移植包裹至2周龄SD大鼠胫骨周围,记录骨膜移植术后1 d、1周、2周、3周、6周两组SD大鼠胫骨影像学变化情况。获取术后第6周两组SD大鼠胫骨组织标本行Micro-CT扫描,分析骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)、骨小梁分离度(Tb.Sp)、骨皮质骨矿物质密度(Cort.BMD)、骨小梁骨矿物质密度(Trabe.BMD)、骨表面积体积比(BS/BV)、骨体积分数(BV/TV)、骨孔隙体积(Po.V)、骨孔隙密度(Po.Dn)等参数。结果实验组术后1周影像表现为移植区骨皮质周围高密度影形成;术后2~3周移植区胫骨纤细、髓腔狭窄,上下端类骨质生成;术后6周胫骨移植区胫骨纤细、髓腔狭窄情况仍存在,而上下端类骨质吸收硬化。实验组Micro-CT扫描表现为水平轴向可见胫骨骨皮质表面凹凸不平,骨髓腔内存在部分高密度影改变;冠状位及矢状位可见胫骨骨皮质密度不均,髓腔稍狭窄,部分骨皮质不连续;3D重建可见胫骨外观不规整,骨表面存在局部凹陷。对照组术后1周影像表现为移植区骨皮质周围高密度影形成;术后2~3周可见胫骨移植区局部骨膜反应,未见髓腔狭窄;术后6周胫骨移植区未见明显异常。对照组Micro-CT扫描水平轴向、冠状位、矢状位及3D重建未见胫骨异常表现。实验组及对照组Tb.Th分别为(0.21±0.03)μm和(0.20±0.03)μm(P=0.79);Th.Sp分别为(0.33±0.01)μm和(0.38±0.04)μm(P=0.24);Th.N分别为(3.23±0.56)mm-1和(3.99±1.00)mm-1(P=0.54);Cort.BMD分别为(9507.00±73.67)g/cm3和(9747.00±130.00)g/cm3(P=0.18);Trabe.BMD分别为(8357.00±25.66)g/cm3和(8905.00±209.40)g/cm3(P=0.06);BS/BV分别为(4.01±0.36)mm-1和(2.98±0.12)mm-1(P=0.06),差异无统计学意义。实验组及对照组BV/TV分别为74.35%±0.86%和81.33%±0.82%(P<0.01);Po.V分别为(7.24±1.90)mm3和(2.48±0.97)mm3(P=0.01);Po.Dn分别为(5.52±0.24)mm-3和(0.95±0.23)mm-3(P<0.01),差异有统计学意义。结论CPT患儿胫骨病变骨膜移植包裹2周龄SD大鼠胫骨后胫骨表现与CPT患儿胫骨临床特征相似,为CPT动物模型的创建提供了一定的参考和依据。

Objective To explore the effect of periosteum derived from congenital pseudarthrosis of the tibia(CPT)on the development of rat tibia and to provide a theoretical basis for establishing CPT animal models.Methods Periosteum samples were collected from CPT and cerebral palsy patients between April and May in 2021.Tibial periosteum in CPT children(CPT group)and children with cerebral palsy(control group)were transplanted and wrapped around tibia of 2-week-old Sprague-Dawley(SD)rats.Radiological changes were observed at Day 1,Week 1,Week 4 and Week 6 postoperatively.And tibial samples harvested from two groups were obtained at Week 6 for Micro-CT scanning to examine the parameters of Tb.Th,Tb.N,Tb.Sp,Cort.BMD,Trabe.BMD,BV/TV,BS/BV,Po.V and Po.Dn.Results Radiological images of CPT group revealed high-density opacities around cortical bone at Week 1.The affected area was significantly thinner than upper and lower ends and bone hyperplasia appeared 2-3 weeks postoperatively.Defect of affected area persisted and hyperplastic bone at upper and lower ends became gradually repaired 6 weeks postoperatively.Micro-CT scan images of CPT group showed irregular thickening of tibial cortex in horizontal view and greater density of medullary cavity.In coronal and sagittal views,thickening of tibial cortex,narrowing of medullary cavity and discontinuity of bone cortex were evident.And 3-D reconstruction hinted at irregularity of tibial cortex and localized depression.In control group,radiology indicated high-density zone around the affected cortical bone 1 week postoperatively.Localized depression in tibial operation area appeared at 2-3 weeks postoperatively and there was no surrounding bone hyperplasia.At Week 6,there was no obvious change in affected area.No abnormal tibia was found on horizontal,coronal,sagittal views and 3D reconstruction of Micro-CT scans.Tb.Th of CPT and control groups were(0.21±0.03)and(0.20±0.03)μm(P=0.79),Th.Sp(0.33±0.01)and(0.38±0.04)μm(P=0.24),Th.N(3.23±0.56)and(3.99±1.00)mm-1(P=0.54),Cort.BMD(9507.00±73.67)and(9747.00±130.00)g/cm3(P=0.18),Trabe.BMD(8357.00±25.66)and(8905.00±209.40)g/cm3(P=0.06)and BS/BV(4.01±0.36)and(2.98±0.12)mm-1(P=0.06).There was no significant inter-group difference.BV/TV were(74.35%±0.86%)and(81.33%±0.82%)(P<0.01),Po.V(7.24±1.90)and(2.48±0.97)mm3(P=0.01)and Po.Dn(5.52±0.24)and(0.95±0.23)mm-3(P<0.01).The inter-group differences were statistically different.Conclusions Pathological periosteum derived from CPT patients suppresses rat tibial development.There are lower bone microstructure parameters and impaired cortical surface.It provides experimental rationales for creating CPT animal models.