Meeting Abstract

P3.51  Sunday, Jan. 6  Cardiac and Renal Developmental Windows for Atenolol Exposure in Embryos of the Chicken Gallus domesticus ROSSITTO, JJ*; BURGGREN, WW; University of North Texas; University of North Texas josierossitto@my.unt.edu

Embryonic development of the cardiovascular and renal organs is usually independently explored. Yet, these organs operate as a highly interactive system in the adult. We studied the ontogeny of these interactions by altering heart rate and blood pressure with Atenolol, a β1-cardioselective blocker, to determine effects on organ mass and renal microstructure in day 18 chicken embryos. Embryos were chronically dosed with Atenolol during the mesonephric stage (E7-E9), mesonephric-metanephric stage (E11-E13), or metanephric stage (E15-E17). Body masses of all Atenolol-treated groups were significantly smaller than the control group (p<0.01) and body mass of the mesonephric group (16.34 ± 0.656 g) was the smallest. Heart mass of the mesonephric group (130.0 ± 5.31 mg) was significantly larger than all other groups (p<0.01). Kidney masses of the mesonephric and metanephric groups were significantly larger than the remaining groups with the mesonephric group showing the largest kidney mass (149.5 ± 6.75 mg, p<0.0001). Nephron number was significantly reduced (p=0.002) by Atenolol in the mesonephric group. Glomerular areas of the mesonephric and metanephric groups were significantly larger than the control group (p<0.001). Surprisingly, day 15 embryos showed a transient increase in mean arterial pressure (MAP) with all but the highest dose (12.0 µg Atenolol/mg of embryonic mass) tested, where MAP actually began to decrease as expected. All doses significantly decreased heart rate. Collectively, these data suggest a day 7-9 critical window of Atenolol sensitivity for cardiovascular and renal development.