COX-2 deletion augments atherosclerosis in apoE

^−/− mice. Optical projection tomographic imaging of the aortic arch from fat-fed apoE^−/−/COX-2^+/+ and apoE^−/−/COX-2^−/− mice (a) demonstrated a clear increase in atherosclerotic lesion burden in the lesser curvature of the arch, and its major branches: the brachiocephalic (BCA), left carotid and left subclavian arteries. Planimetric measurement of plaque area in van Gieson-stained histological sections of the brachiocephalic artery confirmed these observations (b), showing increased plaque area in apoE^−/−/COX-2^−/− mice. Similarly, plasma cholesterol levels (c) and aortic lipid accumulation measured by en face sudan IV staining (d), were increased in apoE^−/− mice lacking COX-2. *; p<0.05 vs apoE^−/−/COX-2^+/+ by unpaired t-test; n = 8-12.