HCV transgenic and non-transgenic mice were perfused through the left ventricle of the heart, first with 10 U/ml heparin in saline until the liver was cleared of blood (about 5 min), then with fixative (2% glutaraldehyde and 2% paraformaldehyde in 0.1M Na Cacodylate, pH 7.4) until the liver was completely fixed (about 6-8 min). Heparin and fixative solutions were delivered by a peristaltic pump (VWR, Westchester, PA, USA) with the flow rate set at 4.5 ml/min. One mm cubes were prepared from the fixed liver and were left to continue fixation at room temperature (RT) overnight. These specimens were processed and embedded in Eponate 12 resin as described above.