The principal findings of our study included the observation that in T1DM patients, HBOT downregulates the iNOS activity/expression by decreasing phosphorylation of ERK1/2 and Akt followed by a decreased activation of NFκB. For this study, we have used HBOT as a medical treatment for T1DM patients with the developed peripheral arterial disease, with the purpose to reduce inflammation and to promote microcirculation. The gene discussed is NOS2; the disease is peripheral arterial disease.