Expression And Clinical Significance Of Neuropeptide Y And Vasoactive Intestine Peptide In Pathological Tissue Of Congenital Pseudarthrosis Of Tibia

ObjectiveThe congenital pseudarthrosis of tibia(CPT)is a stubborn disease in pediatric orthopedics,its major clinical manifestation is non union,and there is still no classical theory to interpret its origin and pathogenesy.Many scholares had considered that neurofibromatosis(NF)was the cause of CPT,but Brown's research on the periost and bone of NF and CPT indicated that CPT was a kind of non neuropathic disease,and there was no direct relationship between them.Lei Wei considered,on the basis of his research in pathohistology and immunohistochemistry,contractible circinate coarctation of periost was the cause of CPT.Now the researches on the origin of CPT are prone to the abnormal periost which lead to non union,whether there is originally abnormal bone metabolism or not is still unknown. Recently peptidergic nerve has become the warm research spot all over the world,it is a kind of nerve different from adrenergic nerve and cholinergic nerve.Peptidergic nerve can take part in the bone metabolism by means of releasing neuropeptide,and it also has effects on the union of fracture.Neuropeptide impacts on region blood flow by its regulation of blood vessel activity,besides,it can regulate the bone metabolism directly by combining with its receptores in the endochylema of osteoblasts and osteoclasts.On these ground,we could presume that CPT may have a relationship with the abnormal expression of some neuropeptide which takes part in the bone metabolism of CPT.The objective of this study is to identify the expression of Neuropeptide Y(NPY) and Vasoactive intestine peptide(VIP)in the pathological tissue of CPT,in order to make a further research for the origin and pathogenesy of CPT.Method1 Material collection(1)Experiment groupThe specimen were the pathological periosteum and bone of pseudarthrosis of 20 CPT patients treated in our department in nearly 30 years.The age of the patients were from 6months to 6 years old,the average is 3.0years.Among them,14 patients were male,and 6 were female.And 12 children's left tibias were invasive,and 8 children's right sides were invasive,there's no patient whose pseudarthrosis were detected in both tibias.(2)Control groupNormal periosteum and bone were taken from CPT children whose fibula were normal and the children who were bow leg during operations,without pathological changes in tibia and fibula.The age range was from 1 to 8 years,and the average age was 3 years and 7 months.2.Paraffin section manufacture in routine method.3.HE stain to observe the pathological changes.4.Immunohistochemistry stain:The sections were processed immunohistochemically to detecte the expression of NPY and VIP in experiment and control groups by means of the avidin-biotin-peroxidase complex(ABC)method,and then observe the expressions of NPY and VIP in two groups under microscopy.5.Data processingSemiquantitative analysis data,the mean positive area(MPA)and mean optical density(MOD)of two neuropeptide substances were acquired by pathology doctors at random in the way of double blind method by Image Pro Plus 5.0(MidiaCybernetics Company).As Tamas' method,to detect the mean vascellum density(MVD)of periosteum in HE-sections under microscopy.Statistical analysis of two group t-test was performed.Results are expressed as means±standard error of means by software SPSS13.0.Results 1.HE stain observationIn the periosteum from CPT patients,the common structure was not observed,instead of a quantity of fibroblasts and disordered hyperplastic collagen fibrils;the number of vascellum was less than control group,with vessel wall thickening and narrow lumina.In bone tissue from CPT patients,there were chaostic bone trabeculas with osteoclasts and osteoblasts around them,fibrous connective tissue compacted in the bone tissue,and there was some cartilage and osteonecrosis.2.Immunohistochemistry stain observationNPY positive substance accumulated in vessel wall and periphery of vessels in periost,and expressed more highly in experimental group than in control group.But no positive substance was observed in osteoblasts and osteoclasts of two groups.VIP positive substance was located at vessel wall in periost and endochylema of osteoclasts and osteoblasts in bone.VIP in periost expressed less in experimental group than in control group,and in osteoclasts more highly,these differences were significant in statistics,but there was no significant difference in osteoblasts between two groups.ConclusionThe expressions of NPY and VIP in pathological periost and bone of CPT were abnormal.For one thing,it decreased the blood flow of bone of pseudarthrosis;for another thing,VIP increased the resorption of bone,both directions impacted on the reconstitution of bone in CPT.It indicated that not only the abnormal periosts,but also the disorder of bone metabolism were the pathological manifestations of CPT,NPY and VIP may be one of causes leading to CPT.