Histochemistry

Cecum sections before and after EDTA chelation were fixed in 4% paraformaldehyde for 48 h, washed with PBS twice, dehydrated in 70% ethanol, and embedded in paraffin. The paraffin blocks were cut into 5-µm sections. The sections were deparaffinized and stained with hematoxylin and eosin (H&E).

Avian IO were rinsed 3 times in ice-cold PBS, fixed with 4% paraformaldehyde for 30 min at room temperature in the wells, and rinsed with ice-cold PBS. Fixed organoids in Matrigel were embedded in paraffin and cut into 5-µm sections. The sections were deparaffinized and stained with hematoxylin and eosin.