Experimental Study On Expression Of VEGF And Its Receptor In Different Developmental Stage Of Human Dental Pulp

Objectives:1.Teeth and endodontium combined Specimens and endodontic sections were produced by decalcification tenique and spliting tooth odonthyalus to compare staining results between them.2.Using immunohistochemistry to detect expression of VEGF,Flt-1and Flk-1 in different developmental stage of human dental pulp and analyse correlation betwween its receptors.3.Using RT-PCR technique to detect gene expression of VEGF,Flt-1and Flk-1 in different developmental stage of human dental pulp and analyse correlation betwween Flt-1and Flk-1.Material and methods:1.Teeth and endodontium combined Specimens and endodontic sections were produced and processed with HE staining,comparing relative merits of the two different slice preparation methods.2. Premolar teeth extracted for orthodontic reason were divided into two groups: group 1 immature permanent,group 2 mature permanent.Sections were pruduceed by the selected method and processed with streptavidin-biotin-peroxidase staining of VEGF,Flt-1 and Flk-1. Using Image-Pro Plus 6.0 and SPSS17.0 package of statistical data to analyze the result.3.Dental pulp was processed with RT-PCR to investigate the gene expression of VEGF,Flt-1 and Flk-1,experimental groups and measurement indicators were the same to part 2. Results:1. Spliting teeth to obtain pulp was simply and quickly. In HE staining tissue was fixed and dehydrated fully and cell morphology was good. For its messy organization, endodontic sections were applicable for morphology and in RT-PCR experiment. While to produce teeth and endodontium combined Specimens was relatively complex :soft tissue was hard to fix and dehydrate and cell morphology wasn't good enough. However,endodontium combined Specimens could be propitious to comparative study of dental pulp.2. In immature permanent,VEGF and Flk-1 were more stongly than mature permanent ,especially in apical area (P <0.05); Flt-1 was more positive in mature permanent than immature ones; The expression of Flt-1 and Flk-1 were negtive correlated to each other(P <0.01).3.Using RT-PCR to detect the mRNA level of VEGF,Flt-1,Flk-1 and found results were the same to the fomer l experiment. Besides,VEGF,Flt-1,Flk-1 were seen in agarose gel at the position of 145bp, 169bp, 162bp, 299bp respectively as expected.Conclusions:1.Though to produce teeth and endodontium combined Specimens is time-consuming and fussy,it can keep dental pulp in full,obtain better staining results,make structure clear,get objective results and is really worth of recommending.2. The expression of VEGF,Flt-1,Flk-1 in dental pulp of immature and mature permanent teeth shows different characteristics. VEGF,Flt-1,Flk-1 may play a role in permanent tooth development and maturation.