Osteoinductive effect β-TCP and vitamin D3 on RUNX2 mRNA expression

Abstract

Although the autograft is regarded as the gold standard bone graft, β-TCP artificial alloplastic is widely used in bone defect healing and has been accepted in human and animal studies to be resorbed and interchanged by vital bone. The active form of vitamin D3 is calcitriol, on mesenchymal stem cells (MSCs) it has a direct influence on encouraging their osteogenic differentiation which is identified as osteoinductive. The need for osteoinductive ability is a demanding issue regarding medical and dental care. RUNX2 regards an essential transcriptional factor for osteoblast differentiation. Adult male New Zealand rabbits (Twenty-four) with an average weight of (1.5-2 kg) were elected in this study. Four holes were made intra-bone in both tibias of each animal. The experimental groups divide as follows: Group C: Bone defect will be left to heal naturally as control; Group TCP: Bone defect will be occupied with β-TCP. Group vitamin D3: Bone defect will be filled with vitamin D3; Group TCPD: Bone defect will be filled with a combination of β-TCP and vitamin D3. Animals sacrificed at (1 and 3 weeks). Purification of total RNA from formalin fixed paraffin embedded (FFPE), The cDNA of RUNX2 and VDR amplify in RT-PCR and detected with sybr green. One-way Analysis of Variance (ANOVA) and least significant difference (LSD) was used as a tool for statistical analysis. Results at 7 days highest mean value of mRNA RUNX2 gene expression Fold Change estimated in TCP followed by TCPD experimental group while at 21 days, the highest mean value in TCPD. All measured parameters showed highly significant differences in the course of healing periods from 7 days to 21 days. In mRNA VDR gene expression parameters showed a highly significant difference in 7days and 21 days durations among experimental groups and the highest mean value of mRNA VDR gene expression Fold Change is recorded in TCPD followed by vitamin D3 groups in both durations. These findings suggest positive inductive effects of local application of vitamin D3 combined with β-TCP as well as vitamin D3 on osteoblast cells and induced bone defect healing.