Elsevier

Journal of Endodontics

Volume 41, Issue 9, September 2015, Pages 1486-1491
Journal of Endodontics

Basic Research
Rosiglitazone Inhibits Proliferation and Induces Osteopontin Gene Expression in Human Dental Pulp Cells

https://doi.org/10.1016/j.joen.2015.05.010Get rights and content

Highlights

  • We evaluated the roles of rosiglitazone on pulp repair.

  • Rosiglitazone significantly decreased cell proliferation.

  • Rosiglitazone did not affect cell viability and apoptosis or necrosis.

  • Rosiglitazone accelerated calcified nodule formation.

  • Rosiglitazone significantly increased osteopontin gene expression.

Abstract

Introduction

Rosiglitazone (RSG) is a synthetic full agonist of transcription factor peroxisome proliferator activated receptor gamma. Previous studies have suggested an anti-inflammatory effect of RSG on lipopolysaccharide-induced pulp inflammation. However, its role in other cellular events related to pulp repair has not been investigated. Therefore, the aim of the present study was to evaluate the effect of RSG on human dental pulp cell viability, proliferation, migration, and osteoblastic/odontoblastic differentiation.

Methods

Cell proliferation was evaluated by [3H]-thymidine assay. Cell viability was assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay and by measuring the percentage of apoptotic cells by flow cytometry. Cell migration was estimated by scratch wound healing assay. Mineralization and cell differentiation were evaluated by alizarin red S staining and real-time polymerase chain reaction gene expression assay, respectively.

Results

RSG significantly decreased cell proliferation and did not have effect on cell viability, apoptosis/necrosis, or migration. Alizarin red S showed that RSG accelerated calcified nodule formation. Results of real-time polymerase chain reaction demonstrated that RSG upregulated osteopontin expression, whereas expression of dentin sialophosphoprotein, dentin matrix protein-1, and osteocalcin was not affected.

Conclusions

These findings suggest that RSG decreases human dental pulp cell proliferation, while positively regulating osteopontin expression.

Section snippets

Human Dental Pulp Cell Isolation and Culture

This study was previously approved by the Ethics Board of the School of Health Science at the University of Brasilia, and informed consent was obtained from all participants. The hDPCs were cultured by using the explant technique (12). Briefly, pulp tissues were obtained from non-erupted, caries-free third molars of young and healthy patients. The tissues were minced into small fragments and placed into 35-mm culture dishes with high-glucose Dulbecco modified Eagle medium (DMEM) supplemented

Rosiglitazone Reduces hDPC Proliferation

RSG (10 μmol/L) inhibited hDPC proliferation after 24 hours by 57.2% ± 4.097% (P < .001), compared with vehicle-treated cells (Fig. 1A). Cell viability was not affected by RSG treatment (Fig. 1B), which also did not induce apoptosis or necrosis of hDPCs (Fig. 1C). Moreover, RSG (10 μmol/L) did not impair hDPC migration ability during the 48-hour period after scratches were made (Fig. 2).

Rosiglitazone Does Not Impair hDPC Mineralization and Increases OPN Expression

Calcified nodule formation was examined after 21 and 28 days of differentiation induction. At day 21,

Discussion

Dentin repair beneath the injury sites is strongly dependent on the severity of inflammation within the pulp tissue 14, 15, 16. Therefore, the ideal agent for vital pulp therapy should be able to modulate dental pulp inflammation while promoting repair events. Previous studies have shown that RSG, a PPARγ full agonist, regulates the expression of inflammatory molecules in hDPCs 6, 7. Nevertheless, its role in regulating the cellular events related to dentin repair has not been elucidated. Our

Acknowledgments

The authors thank Bruna Rabelo Amorim for assistance with images editing.

This work was supported by the grants 620195/2008-8 (MCT/CNPq/CT-Infra/CTPetro) and 564666/2010-6 (CNPq/MCT/FAPDF/CAPES), Brazil.

The authors deny any conflicts of interest related to this study.

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