Bile acid-induced depolarization of mitochondrial membrane potential preceding cell injury in cultured gastric mucosal cells

Effect of the ulcerogenic agents ethanol, acetylsalicylic acid and taurocholate on actin cytoskeleton and cell motility in cultured rat gastric mucosal cells

AIM: To assess the effects of ulcerogenic agents on actin cytoskeleton and cell motility and the contribution of oxidative stress.

METHODS: Rat gastric mucosal cell monolayers were cultured on coverslips. The cells were exposed, with or without allopurinol (2 mmol/L), for 15 min to ethanol (10-150 mL/L), ASA (1-20 mmol/L) or taurocholate (1-20 mmol/L), then the cells were processed for actin and vinculin staining. Cell migration after wounding was also measured.

RESULTS: Exposure to 10 mL/L ethanol caused divergence of zonula adherens-associated actin bundles of adjacent cells and decreased rate of migration. These actions were opposed by xanthine oxidase inhibitor allopurinol. Exposure to 50 mL/L ethanol induced degradation and divergence of zonula adherens-associated vinculin from adjacent cells, which was, again, partially reverted by allopurinol. With 1 mmol/L ASA actin filaments became shorter and thicker. However, higher concentrations (10, 20 mmol/L) of ASA returned microfilaments thinner and longer, and decreased rate of migration. Zonula adherens-associated actin bundles were moderately distorted with 10 mmol/L ASA and with 10 mmol/L taurocholate. Exposure to taurocholate provoked changes resembling those of ASA. Taurocholate 5-20 mmol/L decreased the rate of migration dose dependently. The effects of ASA and taurocholate were not prevented by allopurinol.

CONCLUSION: All ulcerogenic agents decreased the rate of migration dose dependently and induced divergence of zonula adherens-associated actin bundles of adjacent cells. In addition, ethanol and ASA caused degradation of actin cytoskeleton. Oxidative stress seems to underlie ethanol, but not ASA or taurocholate, induced cytoskeletal damage.