Bioluminescence imaging

In mouse xenografts, we used luciferase-expressing breast cancer cells for in vivo bioluminescence imaging using the Xenogen IVIS imaging systems. Breast cancer cells expressing the luciferase gene were implanted into the fat pads of 5-week-old NOD/SCID mice. These mice were imaged at intervals of between 8 and 35 days (see text) during the treatment schedule to monitor tumor behavior. Prior to imaging, the animals were anesthetized with a mixture of oxygen (1:1) and 2.5% isoflurane in a clear induction chamber. After initial exposure to anesthesia, the mice were positioned in the supine position inside the imaging system: throughout the session, animal anesthetization was maintained at ~1.25% isoflurane.