3.7. Ki67-positive crypt epithelial cells in the small intestine of
PEDV-inoculated nursing piglets vs. weaned pigs
In frozen jejunal tissues of the uninoculated nursing pigs at PIDs
1–5, small to moderate numbers of Ki67-positive cells were
detected in the small intestinal crypts (Fig. 6A and E). Ki67 protein
was expressed and localized in the nuclei of crypt epithelial cells by
IF staining (Fig. 6A–D). PEDV-inoculated nursing pigs tested at PIDs
1–5 exhibited large numbers of Ki67-positive cells in the crypts of
the small intestine (Fig. 6B and E). Unlike nursing piglets,
uninoculated or PEDV-inoculated weaned pigs tested at PIDs
1–5 exhibited large numbers of Ki67-positive cells in the crypt
cell layers of the small intestine (Fig. 6C–E). At PIDs 1–5, mean
Ki67-positive scores in the small intestine of uninoculated nursing
pigs were significantly lower than those in the other groups (P < 0.01 at each-time point). However, there were no significant
differences in mean Ki67-positive scores among the other three
groups at PIDs 1–5.