Gene expression analysis of membrane transport proteins in normal and lipopolysaccharide-inflamed rat dental pulp.

INTRODUCTION: Membrane transport proteins (transporters) play a crucial role in the transmembrane uptake and/or efflux of various compounds such as inorganic ions, endogenous bioactive substances such as prostaglandins (PGs), and drugs such as nonsteroidal anti-inflammatory drugs. This study aimed to analyze mRNA expression of selected transporters related to drug disposition and PG transport in normal and lipopolysaccharide (LPS)-inflamed rat incisor pulp.

METHODS: Pulp tissues were subjected to reverse transcription-polymerase chain reaction (PCR) detection for transporter isoforms belonging to organic anion transporting polypeptide (Oatp), organic anion transporter (Oat), organic cation transporter (Oct), multidrug resistance-associated protein (Mrp), and multidrug resistance protein (Mdr) families. The levels of mRNA expression for PG transporters (Oatp1a5, Oatp1b2, Oatp2a1, Oatp2b1, and Oatp3a1) were compared in normal and LPS-inflamed pulps by using real-time PCR.

RESULTS: The pulp tissue expressed mRNAs for various transporters belonging to the Oatp, Oat, Oct, Mrp, and Mdr families. LPS inflammation caused significant up-regulation of Oatp2a1 (P < .01) and significant down-regulation of Oatp1a5, Oatp2b1 (P < .01), and Oatp3a1 (P < .05).

CONCLUSIONS: Rat incisor dental pulp expressed mRNAs for various transporter isoforms. The levels of mRNA expression for PG transporters were significantly up-regulated or down-regulated in LPS-inflamed dental pulp.