Inhibition of NF kappa B activation by pyrrolidine dithiocarbamate prevents in vivo hypoxia/reoxygenation-mediated myocardial angiogenesis.

This study sought to examine the effect of nonlethal moderate whole body hypoxic challenge (10% 02/90% N2) on rat myocardial angiogenesis. Sprague Dawley rats were subjected to 4 h of systemic normobaric hypoxemic hypoxia (10 +/- 0.4% O2) in an anesthesia chamber or to 4 h of normoxia (ambient 20.9 +/- 0.4% O2) to time-match the duration of hypoxia. All rats were then kept under normoxic conditions. Rats were sacrificed and hearts harvested either after 2 h for subsequent electrophoretic mobility gel shift assay for NF kappa B, or after 24 h for subsequent Western blot analysis for vascular endothelial growth factor (VEGF) and after 7 days for immunohistochemistry for capillary density measurement. We also used pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF kappa B, before 1 h of hypoxia to establish the possible role of NF kappa B in modulating myocardial angiogenesis. The results showed significant induction of VEGF protein expression after 4 h of hypoxia followed by 24 h of reoxygenation in the rat myocardium. The DNA binding activity of NF kappa B was increased compared with the hypoxic group. However inhibition of NF kappa B by PDTC decreased capillary density significantly when compared with the hypoxic group. These findings demonstrate the role of NF kappa B and VEGF in myocardial angiogenesis for the first time.