Nitric Oxide Synthesis by Rat Pleural Mesothelial Cells: Induction by Growth Factors and Lipopolysaccharide

The purpose of this study was to determine if certain growth factors and bacterial products induce pleural mesothelial cells (PMC) to produce nitric oxide (NO). Confluent monolayers of rat PMC were exposed to epidermal growth factor (EGF), platelet-derived growth factor (PDGF), or lipopolysaccharide (LPS) individually and in various combinations for 24-72 h. Concentrations of nitrite and nitrate were quantified and used as an indirect measure of NO production. LPS stimulation resulted in a significant increase in nitrite/nitrate concentration, but neither EGF nor PDGF alone or combined had any significant effect relative to control. However, LPS combined with either EGF or PDGF caused a significant increase in nitrite/ nitrate concentration relative to LPS alone and growth factor alone. The highest level of nitrite/nitrate concentration was observed with the triple combination of LPS, EGF, and PDGF. Nitrite/nitrate accumulation was significantly increased at 24 h by all combinations, and continued to incr...