Ethanol retards gastric epithelial restoration in monolayer cultures

Protective effect of a novel rice extract against ethanol-induced gastric mucosal injury in rat

The aim of this study was to investigate the protective action of rice extract on ethanol-induced mucosal damage in vivo and wound healing of epithelial cells in vitro. Also, the effect of rice extract on gastric mucosal prostaglandin E(2) level, HSP72 expression, gastric acid secretion, and contribution of vanilloid receptor-mediated action was studied. In addition, using cultured gastric mucosal cells (RGM-1), the effect of rice extract on cytoprotection and wound healing of epithelial cells was evaluated. Rice extract significantly reduced gastric mucosal damage produced by ethanol in vivo, and heat treatment (80 degrees C, 3 min) of this agent did not alter its protective effect. Rice extract also protected RGM-1 from ethanol-induced damage in a dose-dependent manner. Rice extract accelerated wound healing of gastric epithelial cells. Our results demonstrate that rice extract could be an alternative ulcer treatment that provides cytoprotection and enhancement of wound healing not dependent on acid secretion, prostaglandin E(2) level, HSP72 expression, or vanilloid receptors.

Valproate, thalidomide and ethyl alcohol alter the migration of HTR-8/SVneo cells

BACKGROUND

Valproate, thalidomide and alcohol (ethanol) exposure during the first trimester of pregnancy is known to cause several developmental disorders. All these teratogens are known to pass the placental barrier and interfere directly with the normal development of the fetus. However, these teratogens also alter the formation and function of the placenta itself which may in turn affect the proper nourishment and development of the fetus. Optimum development of the placenta requires adequate invasion of trophoblast into the maternal uterine tissues. Changes in the migratory behavior of trophoblast by maternal exposure to these teratogens during placentogenesis may therefore alter the structure and function of the placenta.

METHODS

In the present study, the effects of sodium valproate, thalidomide and alcohol on the migration of human first trimester trophoblast cell line (HTR-8/SVneo) were examined in vitro. Cells were cultured in the wells of 48-well culture plates as mono or multilayers. Circular patches of cells were removed from the center of the wells by suction, and the migration of cells into the wound was studied using microscopy. Effects of low and high concentrations of valproate, thalidomide and alcohol were examined on the healing of wounds and on the migration rate of cells by determining the wound areas at 0, 3, 6, 12, 24 and 48 h. Effects of drugs and alcohol on the proliferation and the expression levels of integrin subunits beta1 and alpha5 in cells were examined.

RESULTS

The migration rates of trophoblast differed between wounds created in mono and multilayers of cells. Exposure to teratogens altered the migration of trophoblast into mono and multilayer wounds. The effects of valproate, thalidomide and alcohol on the proliferation of cells during the rapid migratory phase were mild. Drug exposure caused significant changes in the expression levels of beta1 and alpha5 integrin subunits.

CONCLUSION

Results suggest that exposure to valproate, thalidomide or alcohol during the first trimester of pregnancy may change the ultrastructure of the placenta by altering the migration of trophoblast cells and this effect may be mediated by drug- or alcohol-induced changes in the expression levels of beta1 and alpha5 integrin subunits.

Gastroprotective and ulcer-healing effect of new solidagenone derivatives in human cell cultures

The labdane diterpene solidagenone 1 and its semisynthetic and biotransformation derivatives 2-10 were assessed for gastroprotective and ulcer-healing effect using human epithelial gastric cells (AGS) and human lung fibroblasts (MRC-5). The ability of the compounds to protect the AGS cells against the damage induced by sodium taurocholate (NaT), to stimulate the cellular reduced glutathione (GSH), prostaglandin E(2) content, enhance AGS and MRC-5 cell proliferation and to scavenge superoxide anion in vitro was studied. The cytotoxicity of the compounds was assessed towards MRC-5 fibroblasts and AGS cells. A significant reduction of cell damage after NaT incubation was observed when the AGS cells were pretreated with compounds 2 and 6. Treatment with compounds 4-6, 8 and 9 significantly stimulated the GSH content in AGS cell cultures. None of the studied compounds was active as a superoxide anion scavenger. In AGS cells treated with compounds 1-10, only compound 5 was able to increase prostaglandin content. Concerning the proliferation assays, a significant stimulating effect was observed for compounds 2, 8, 9 on AGS cells and for 5, 7-9 on MRC-5 fibroblasts. Regarding cytotoxicity, solidagenone showed higher toxicity while compounds 4 and 7 were the less toxic. Our results showed that most of the studied compounds act in vitro as gastroprotectors increasing the cellular GSH content. Additionally, some derivatives exhibited in vitro ulcer-healing effect stimulating the cell proliferation.

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.

Effect of essential oil obtained from Croton cajucara Benth. on gastric ulcer healing and protective factors of the gastric mucosa

The bark of Croton cajucara Benth. (Euphorbiaceae) is used widely in Amazonian folk medicine for the treatment of a wide range of gastrointestinal symptoms. Infusions of C. cajucara bark contain dehydrocrotonin (DHC), the furan diterpene, and an essential oil, a rich mixture of sesquiterpenes. Although the antiulcerogenic activity of the essential oil has been studied in different gastric ulcer models in mice and rats, its mechanism remains unclear. In this work, we examined the ability of this essential oil to increase PGE2 release from mucus cells, as well as its effects on the amount of gastric mucus and on the healing of acetic acid-induced gastric ulcers. The essential oil (100 mg/kg body wt., p.o), significantly increased PGE2 production by glandular cells (by 102% as compared to control) and the amount of Alcian blue binding to the gastric mucus. In chronic gastric ulcers, a single daily oral dose of essential oil (100 mg/kg body wt.) for 14 consecutive days accelerated ulcer healing to an extent similar to that seen with an equal dose of cimetidine. Thus, the protective and healing actions of the essential oil from C. cajucara bark on gastric lesions resulted mainly from an increase in PGE2 release and gastric mucus formation which would protect the gastric mucosa.

Influence of gender difference and gastritis on gastric ulcer formation in rats

BACKGROUND

Male patients with gastritis are found to have a high risk of developing peptic ulcer diseases. However, how gastritis or gender difference affects gastric ulcer formation is unclear. The present study aimed to investigate the relationship between ethanol-induced acute gastritis and gastric ulcer formation in rats.

METHODS

Acute gastritis or gastric ulcer was induced in the rat stomach by 80% ethanol or 60% acetic acid, respectively. Rats were killed either with gastritis alone or thereafter at day 1, 3 or 6 after ulcer induction. The number of proliferating and apoptotic cells, the mucosal mucus and prostaglandin E(2) (PGE(2)) level were also determined.

RESULTS

Male rats with acute gastritis potentiated gastric ulcer formation, while gastritis in female rats prevented ulceration. Female rats with gastritis had a significantly faster ulcer-healing rate. More apoptotic cells were found in the gastritis groups, but only the female gastritis group produced more proliferating cells and had a decrease in the apoptosis-over-proliferation ratio. The mucus level was higher in female rats after ulcer induction. Mucosal PGE(2) level was higher in female rats with acute gastritis. Both mucus and PGE(2) were increased during ulcer healing in both genders.

CONCLUSIONS

This study shows that gender difference plays a role in the pathogenesis of ulcer formation. The number of cells with apoptosis or proliferation determines, in part, the gender difference on gastric ulcer formation in rats. Gastric PGE(2) not only contributes to this process, but also together with gastric mucus participates in the ulcer-healing process in the stomach.