TNF-induced enterocyte apoptosis and detachment in mice: Induction of caspases and prevention by a caspase inhibitor, ZVAD-fmk

Injection of mouse recombinant TNF to mice induced apoptosis and detachment of the enterocytes of the tip of the villi, evident after 30 to 90 minutes , which resulted in a shrinkage of the villi. Injection of TNF increased th e expression of caspase 1, 2, 3, and 6 as well as of cathepsin D in the muc osal wall, which was maximal 30 minutes after TNF injection. Caspase 1 and 3 were not induced in TNFR1-deficient mice in which TNF does not induce apo ptosis and detachment. The administration of a caspase inhibitor (ZVAD-fmk, 300 mu g) decreased enterocyte detachment and apoptosis, as well as villus atrophy, whereas a caspase 3 inhibitor (Z-DEVD-cmk) had no effect. The res ults indicate that the induction of caspases by TNF is the cause of their d etachment in the lumen and of the resulting villus atrophy.