Abstract P211: Single High Na + Ingestion Leads To An Increase In Oxidative Stress And Triggers Inflammation.

Hypertension has been linked to a progressive increased in oxidative stress and inflammation. The high prevalence of hypertension poses a great risk to public health as 108 million adults in the United States have the condition. For that reason, a better understanding of the link between a high Na+ intake and the development of hypertension is of crucial importance. We hypothesize that a single ingestion of a high Na+ solution leads to increased oxidative stress and triggers an inflammatory response. Wistar 200-250 g male rats had gastric infusions through the esophagus. Groups were infused with 8 mL liquid Vaseline (Control), 8 mL of NaCl 0.684 M (4% m/v), and 8 mL of NaCl 1.368 M (8% m/v). After infusion, blood was collected at different time points during the first hour. Tissue samples were obtained from the aorta, heart, and kidney. Electron Microscopy (EM) was performed on all tissues, which were also analyzed for molecular markers of oxidative stress: Superoxide Dismutase (SOD) and Malondialdehyde (MDA), and an inflammation marker: Extracellular Signal-Regulated Kinase (ERK). At 2 and a half minutes, serum Na+ concentration was unchanged in the control group compared to an increase observed in animals receiving 4% and 8% Na+ with concentrations of 135±1.4 mEq/L, 141±2.0 mEq/L, and 140±1.2 mEq/L respectively. At the 1-hour time point after infusion, the difference was further increased in the 8% group with serum concentrations of 135±1.8 mEq/L, 140±1.5 mEq/L, and 152±1mEq/L respectively (p<0.05). There was an increase in oxidative stress in the aorta from values of 36.22±4.64 mU/mg SOD and 0.131±0.013 pg/mL MDA in the control group, to 47.11±4.89 mU/mg SOD and 0.291±0.022 pg/mL MDA in the 8% group (p<0.05 in both cases). The same was observed in the heart, where values were: 174.6125.26 mU/mg SOD, 0.026±0.007 pg/mL MDA in controls, and 259.22±21.98 mU/mg SOD, 0.215±0.073 pg/mL MDA in 8% group (p<0.05 both cases). Increased ERK in aortic tissue, values of 0.29±0.03 pg/mL in controls, 2.68±0.18 pg/mL in 4% group and 3.97±0.68pg/mL in 8% group (p<0.05) suggest increased inflammation. We conclude that the elevation in serum Na+ concentration that follows Na+ ingestion leads to increased oxidative stress and inflammation.