Cardiac Hypertrophy and Ventricular Contractility in Rats Exposed to Neonatal Supplemental Oxygen and High Fat Diet

Premature birth represents about 13% of live births each year. Since lungs of these infants are underdeveloped, they receive supplemental oxygen right after birth, but little is known about its effects on the development of normal physiological responses and whether it impacts long‐term cardio‐metabolic function. Based on previous studies from our lab that showed increased pulse wave velocity in 12 month old rats exposed to neonatal supplemental oxygen, we hypothesized that neonatal exposure to supplemental oxygen causes cardiac hypertrophy and decreased left ventricular contractility. We also hypothesized that these effects to supplemental oxygen would be enhanced by 10 weeks on a high fat diet. To test the hypothesis, we used our rat model of OXY and CON rats exposed to FlO 2 =0.80 and 0.21 respectively, for 8 days post‐birth. Two months after birth, these OXY and CON rats were randomly assigned to either a high fat diet (60% of calories from animal fat) or low fat diet for 10 weeks during which their weights and caloric consumptions were monitored. After 10 weeks, a Miller conductance catheter was inserted into the left ventricle to obtain pressure volume loops and end‐systolic pressure volume relationship, which was used to evaluate contractility. OXY rats tended to have larger left ventricles (1.40±0.24 g vs 1.18±0.08g) and OXY rats fed a high fat diet showed greater average weight gain than CON rats on the same diet. There was no difference in contractility. These data suggest that neonatal supplemental oxygen may promote left ventricular hypertrophy and weight gain. Support or Funding Information The University of Iowa Start‐Up Fund