The effect of graft application and allopurinol treatment on calvarial bone defect in rats1

Involvement of MiRNA-211-5p and Arhgap11a Interaction During Osteogenic Differentiation of MC3T3-E1 Cells

Objective

MicroRNAs (miRNAs) are well-recognized for their abilities to regulate gene expression post-transcriptionally in plants and animals. Recently, miRNA-messenger RNA (mRNA) regulatory relationships have been confirmed during biological processes, including osteogenic differentiation. This study aimed to find out more candidate miRNA-mRNA pairs involved in the osteogenic differentiation of MC3T3-E1 cells.

Methods

An MC3T3-E1-based microarray dataset (accessioned as GSE46400) downloaded from the Gene Expression Omnibus included MC3T3-E1 cells with or without 14-day osteoblast differentiation osteoblast induction. Multiple miRNA-mRNA prediction databases were searched by differentially expressed genes (DEGs) to obtain pairs of a miRNA-DEG regulatory network. The MC3T3-E1 cells were cultured and incubated in the osteogenic differentiation medium for 14 days. The expressions of candidate miRNAs and mRNAs were determined by real-time quantitative PCR(RT-qPCR) in MC3T3-E1 cells. The miRNA-mRNA interactions were verified by dual-luciferase reporter gene assays and experiments using mimics miRNA or their inhibitors.

Results

We identified 715 upregulated DEGs and 603 downregulated DEGs between MC3T3-E1 cells with and without osteoblast induction by analyzing the raw data of the GSE46400 dataset. There were 7 overlapped miRNA-mRNA pairs identified during osteogenic differentiation of MC3T3-E1 cells, including mmu-miR-204-5p-Arhgap11a, mmu-miR-211-5p-Arhgap11a, mmu-miR-24-3p-H2afx, mmu-miR-3470b-Chek2, mmu-miR-3470b-Dlgap5, mmu-miR-466b-3p-Chek1, and mmu-miR-466c-3p-Chek1. The Arhgap11a, H2afx, Chek2, Dlgap5, and Chek1 were hub genes downregulated in MC3T3-E1 cells after osteogenic differentiation, verified by RT-qPCR results. The RT-qPCR also determined declined expressions of miR-204-5p and miR-24-3p concomitant with elevated expressions of miR-211-5p, miR-3470b, miR-466b-3p, and miR-466c-3p in the MC3T3-E1 cells, with osteoblast induction compared with undifferentiated MC3T3-E1 cells. Dual-luciferase reporter gene assays demonstrated Arhgap11a as the target of miR-211-5p. MiR-211-5p upregulation by its mimic increased Arhgap11a expression in MC3T3-E1 cells.

Conclusion

Our study characterizes miR-211-5p targeting Arhgap11a promotes the osteogenic differentiation of MC3T3-E1 cells, which provides novel targets to promote the osteogenesis process during bone repair.

Platelet-concentrated and platelet poor-plasma promote different pattern on immunohistochemical expression of TGF-β1, however they impairs the osteoneogensis in calvarial defects treated with autograft due suppression of osteocalcin

Purpose

Herein we evaluated the effects of platelet concentrate (PC) and platelet-poor plasma (PPP) on bone repair using noncritical defects in the calvaria of rabbits and compared them to the presence of TGF-β1 and osteocalcin on reparative sites.

Methods

Five noncritical defects of 8.7 mm in diameter were created on the calvaria of 15 animals. Each defect was treated differently, using autograft (ABG), ABG associated with PC (ABG + PC), ABG with PPP (ABG + PPP), isolated PPP, and blood clot (control). The animals were submitted to euthanasia on the second, fourth and sixth week post-surgery.

Results

The defects that received ABG+PC or PPP demonstrated lower bone formation when compared to specimens that received ABG in the same period. These results coincided to significant higher immunopositivity for TGF-β1 for specimens that received PC, and lower presence of cytokine in the group PPP. However, either higher or lower presence of TGF-β1 were also correlated to lower presence of osteocalcin. Likewise, these results were similar to findings in specimens treated only with PPP when compared to control.

Conclusions

PC and PPP were not effective when applied in association with ABG. Similarly, isolated use of PPP was not beneficial in optimizing the bone repair.

Short-term use of resveratrol in alloplastic graft material applied with calvarial bone defects in rats

PURPOSE

The effects of resveratrol administration on calvarial bone defects with alloplastic graft material was investigated for osteoinductive reaction and bone development in rats.

METHODS

Healthy male rats were randomly divided into 3 groups consisting of 10 rats. Groups were as follows: control (defect) group, defect + graft group, and defect + graft + resveratrol group. A calvarial bone defect was created in all groups, alloplastic bone grafts were applied to the defect in the 2nd and 3rd group, resveratrol (5 mg/kg/day) was added to the drinking water of the animals following graft application for 28 days in the 3rd group.

RESULTS

Increase in osteoclasts and necrotic changes were observed histopathologically in the control group. In the 2nd group, reduction of inflammation, congestion of blood vessels, increased osteblastic activity, osteoinductive effect, progression of osteocyte development and increased collagen fibers in connective tissue were observed. In the 3rd group, osteoblasts seemed to secrete bone matrix and accelerate osteoinductive effect with increased osteopregenitor activity and positive osteopontin and osteonectin expressions.

CONCLUSION

Resveratrol treatment was thought to be an alternative and supportive drug for implant application by inducing new bone formation in the calvaral defect region as a result of short-term treatment.