Figure 3

Loss of A1ARs in cardiac tissue leads to reduced heart tissue under hypoxic conditions. Pregnant dams were exposed to hypoxia for 3 days from E8.5-E11.5 before embryos were collected. (A) Using Image-Pro Plus software, the cross-sectional area of the ventricle throughout the heart and at the level of the AV canal was measured as well as the area of the AV and OFT cardiac cushions. Hypoxia caused a 25% decrease in the area of myocardial tissue both overall and at the level of the AV canal in the Hypox/Flox group. In the Hypox/Cre group, with A1AR deleted from cardiomyocytes, the decrease in area was more severe, 65% overall and 52% at the level of the AV canals. The AV canal cushions (30%) and OFT cushions (26%) were reduced in size in the Hypox/Flox group. Both room air groups (B) Normox/Flox and (C) Normox/Cre exhibited normal morphology and size. (D) Hypox/Flox hearts were normal in morphology but truncated in size, where as the (E) Hypox/Cre hearts displayed disrupted morphology and severely reduced size. *, P ≤ 0.05; **, P ≤ 0.01 by student's t-test. Scale bar is 200 μm.