Early Effects of Hyperbaric Oxygen on Inducible Nitric Oxide Synthase Activity/Expression in Lymphocytes of Type 1 Diabetes Patients: A Prospective Pilot Study

Abstract

This study aimed at examining the early effects of hyperbaric oxygen therapy (HBOT) on inducible nitric oxide synthase (iNOS) activity/expression in lymphocytes of type 1 diabetes mellitus (T1DM) patients. A group of 19 patients (mean age: 63 ± 2.1) with T1DM and with the peripheral arterial disease were included in this study. Patients were exposed to 10 sessions of HBOT in the duration of 1 h to 100% oxygen inhalation at 2.4 ATA. Blood samples were collected for the plasma C-reactive protein (CRP), plasma free fatty acid (FFA), serum nitrite/nitrate, and serum arginase activity measurements. Expression of iNOS and phosphorylation of p65 subunit of nuclear factor- κ B (NF κ B-p65), extracellular-regulated kinases 1/2 (ERK1/2), and protein kinase B (Akt) were examined in lymphocyte lysates by Western blot. After exposure to HBOT, plasma CRP and FFA were significantly decreased ( p < 0.001 ). Protein expression of iNOS and serum nitrite/nitrate levels were decreased ( p < 0.01 ), while serum arginase activity was increased ( p < 0.05 ) versus before exposure to HBOT. Increased phosphorylation of NF κ B-p65 at Ser 536 ( p < 0.05 ) and decreased level of NF κ B-p65 protein ( p < 0.001 ) in lymphocytes of T1DM patients were observed after HBOT. Decreased phosphorylation of ERK1/2 ( p < 0.05 ) and Akt ( p < 0.05 ) was detected after HBOT. Our results indicate that exposure to HBO decreased iNOS activity/expression via decreasing phosphorylation of ERK1/2 and Akt followed by decreased activity of NF κ B.