Anti-inflammatory effect of peroxisome proliferator activated receptor gamma on human dental pulp cells

Peroxisome proliferator activated receptor gamma (PPARgamma) plays a critical role in controlling immune and inflammatory responses. However, its effect on pulpal inflammation has not been clarified. The purpose of this study was to determine the anti-inflammatory effect of PPARgamma on pulpal inflammation. Human dental pulp cells treated with lipopolysaccharide exhibited elevated levels of matrix metalloproteinase-2 (MMP-2), MMP-9, intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). However, when treated with rosiglitazone (PPARgamma agonist) or adenoviral PPARgamma in same culture system, the expression of ICAM-1 and VCAM-1 was markedly inhibited along with decreased secretion of MMPs. In addition, the coadministration of GW9662 (PPARgamma antagonist) and rosiglitazone blocked the inhibition of MMP-2, MMP-9, ICAM-1, and VCAM-1. These results suggest that PPARgamma decreased the production of MMPs, ICAM-1, and VCAM-1 and might offer a possible attempt of using it as one of anti-inflammatory modulators in a pulpal inflammation.