Figure 1. Cultured mouse primary intestinal epithelial cells under an inverted phase-contrast microscope. (A) The single crypts
obtained with collagenase-hyaluronidase dissociation of mouse small intestine. (B) A few cells gradually migrated out around the crypts after 24 h. (C)
The epithelial cells started to grow rapidly after 48 h, and multiple large colonies were formed at day 5. (D) Cells continued to grow until confluence
was reached after 9 days.