Objective
To determine the expression of nitric oxide synthases (NOSs) and their modulation by hypoxia in human peritoneal (NF) and adhesion fibroblasts (ADF). Design: Prospective experimental study. Setting: University medical center. Patient(s): Fibroblasts from peritoneum and adhesion tissues. Intervention(s): Hypoxia and silencing inducible NOS (iNOS) gene expression in fibroblasts. Main outcome measure(s): We used reverse-transcriptase polymerase chain reaction to quantify messenger RNA (mRNA) levels of NOS isoforms. Griess assay was used to measure NO levels. Result(s): The mRNA copies/mug RNA of neuronal NOS (nNOS) and endothelial NOS (eNOS) were 6.6 x 10(3) in NF, 5.7 x 10(3) in ADF and 7.0 x 10(3) in NF, 6.1 x 10(3) in ADF, respectively. The mRNA copies/mug RNA of iNOS were 31.3 x 10(3) in NF and 33.0 x 10(3) in ADF. Hypoxia increased iNOS mRNA copies/mug RNA from 31.3 x 10(3) to 61.3 x 10(3) in NF and from 33.0 x 10(3) to 63.9 x 10(3) in ADF, whereas there were no changes in mRNA levels of nNOS and eNOS in NF and ADF. Nitric oxide levels were lower in ADF (0.94 micromol/L) than NF (1.97 micromol/L). Silencing iNOS decreased NO levels in NF (from 1.97 micromol/L to 0.41 micromol/L) and in ADF (from 0.94 micromol/L to 0.27 micromol/L).