['Pericytes are multifunctional, polymorphic perivascular cells that lie within the microvessel basal lamina, are located on the abluminal side of endothelial cells, and are thought to play a regulatory role in capillary leak observed in sepsis. Toll-Like receptor 4 (TLR-4) has been implicated as the proximal transmembrane receptor for the LPS/CD 14 complex during the activation of lipopolysacharide (LPS)-induced sepsis. It is our hypothesis that TLR-4 is present on lung pericytes and is up-regulated in response to LPS.', 'Rat microvascular lung pericytes were isolated and cultured. Cells from passage 3-5 were used and treated with LPS (control, 10 ng/mL, and 100 ng/mL) for 18 h. Immunostaining and immunoblotting were performed to detect the presence of CD-14, TLR-2, and TLR-4. Real-time polymerase chain reaction was used to analyze the presence and quantity of mRNA for CD-14, TLR-2, and TLR-4.', 'Immunostaining and immunoblotting revealed the presence of CD-14, TLR-2, and TLR-4 in pericytes from each treatment group, and real-time polymerase chain reaction confirmed the presence of mRNA for CD-14, TLR-2, and TLR-4. An increase in the mRNA was observed in CD-14, TLR-2, and TLR-4 in the presence of increasing LPS 4 h after treatment. At 18 h after LPS treatment, a decrease in mRNA was noted.'] Is toll-like receptor-4 message up-regulated in lipopolysaccharide-exposed rat lung pericytes?