Fig. 1. MhAT3F hepatocytes form organoids in Matrigel. Phase-contrast microscopy of monolayer grown cells (a) and organoids formed after 8 days of culture in Matrigel (b). After 4 days of culture, most of the organoids were filled with cells (c), whereas, at day 8, most were hollow (d) as visualized by Hoechst 33258 nuclear staining (blue). Multiple lumens are visualized on semi-thin sections of day 8 organoids (e,f). Apoptotic bodies (ab) and debris can be seen within some lumens (L) (e), whereas others contained no dense material (f). n, nucleus. Before lumen formation, cells in the interior of the organoids contain activated caspase 3 (green) (g). Bars, 20 µm (a-d,g), 3.5 µm (e,f).