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

Abstract

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 (9 507.00±73.67) and (9 747.00±130.00) g/cm3 (P=0.18), Trabe.BMD (8 357.00±25.66) and (8 905.00±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.