Gastric irritant-induced apoptosis in guinea pig gastric mucosal cells in primary culture.
When the gastric mucosa is exposed to various irritants, apoptosis and subsequent gastric mucosal lesion can result in vivo. We here show that gastric irritants induced apoptosis in gastric mucosal cells in primary culture and examined its molecular mechanism. Ethanol, hydrogen peroxide, and hydrochloric acid all induced, in a dose-dependent manner, cell death, apoptotic DNA fragmentation, and chromatin condensation, suggesting that each of these gastric irritants induced apoptosis in vitro. Since each of these irritants decreased the mitochondrial membrane potential and stimulated the release of cytochrome c from mitochondria, gastric irritant-induced apoptosis seems to be mediated by mitochondrial dysfunction. Caspase-3, caspase-8, and caspase-9-like activities were all activated simultaneously by each of these irritants and the activation was concomitantly with cell death and apoptotic DNA fragmentation. Furthermore, pre-treatment of gastric mucosal cells with an inhibitor of caspase-8 suppressed the onset of cell death as well as the stimulation of caspase-3- and caspase-9-like activities caused by each of these gastric irritants. Based on these results, we consider that caspase-8, an initiator caspase, plays an important role in gastric irritant-induced apoptosis.
Tsutsumi
Shinji
S
Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, 700-8530, Okayama, Japan
Tomisato
Wataru
W
Takano
Tatsunori
T
Rokutan
Kazuhito
K
Tsuchiya
Tomofusa
T
Mizushima
Tohru
T
D000818:Animals; D017209:Apoptosis; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D004789:Enzyme Activation / Q000187:drug effects; D000431:Ethanol / Q000633:toxicity; D005753:Gastric Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006168:Guinea Pigs; D006851:Hydrochloric Acid / Q000633:toxicity; D006861:Hydrogen Peroxide / Q000633:toxicity; D007425:Intracellular Membranes / Q000187:drug effects; D007509:Irritants / Q000633:toxicity*; D008564:Membrane Potentials; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology
D061945:Caspase Inhibitors; D003574:Cytochrome c Group; D007509:Irritants; D000431:Ethanol; D006861:Hydrogen Peroxide; D020169:Caspases; D006851:Hydrochloric Acid