Increased cerebral and renal endothelial nitric oxide synthase gene expression after cardiopulmonary bypass in the rat

Left panels, Rectal temperature (upper left panel), mean arterial pressure (middle left panel), and hemoglobin concentration (lower left panel) in sham (closed circle), CPB (open circle), and CPB anemia (closed triangle) rats. The initial measurement at baseline was compared with values during 1 hour of CPB (CPB, 15 to 75 minutes). The initial drop in hemoglobin occurred as a result of mild hemodilution in sham and CPB rats. This decrease was significantly greater in anemic rats, which underwent a more severe degree of hemodilution. There were no significant differences in mean arterial pressure or temperature between groups. Right panels, pH (upper right panel), Paco₂(middle right panel), and Pao₂(lower right panel) in sham, CPB, and CPB anemia rats. There were no significant differences in pH, Paco₂ and Pao₂ when CPB, CPB anemia, and sham animals were compared. *P < .05 relative to baseline and between groups. CPB, cardiopulmonary bypass.

Real time quantitative RT-PCR analyses of GAPDH, eNOS, and VEGF mRNA levels in cerebral cortex, renal cortex, and renal medulla of sham, CPB, and CPB anemia rats. No differences in mRNA levels for the control gene GAPDH were observed among groups in any tissue. Cerebral cortical eNOS mRNA was significantly elevated after CPB, but not further increased by CPB and anemia. In renal cortical tissue, CPB did not result in any significant change in eNOS mRNA levels; however, CPB and anemia tended to increase eNOS expression. In the renal medulla, CPB and anemia resulted in a large increase in eNOS mRNA levels relative to sham and CPB groups. No increase in mRNA was observed for the hypoxic gene VEGF. However, CPB and anemia resulted in a significant reduction in VEGF mRNA levels in both the cerebral and renal cortex. *P < .05 relative to sham; #P < .05 relative to the CPB group. PCR, polymerase chain reaction; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; eNOS, endothelial nitric oxide synthase; VEGF, vascular endothelial growth factor; mRNA, messenger RNA; CPB, cardiopulmonary bypass.