Assessment of the actions of prostanoids in the protection and repair of the gastric mucosa.
The ability of prostaglandin E2 (PGE2) and its analogue, 16,16-dimethyl PGE2 (dmPGE2) to protect the rat gastric mucosa from damage has been investigated using the release of enzyme markers as an index of surface cell disruption. These studies have been extended to investigate whether prostanoids can also enhance the rapid repair process which re-establishes epithelial continuity. With low oral doses of PGE2 (100 micrograms kg-1) and dmPGE2 (2.5 micrograms kg-1), the deep necrotic damage induced by intragastric instillation of ethanol was inhibited, yet the mucosal enzyme release (acid phosphatase and lactate dehydrogenase) determined in vitro was unaltered. At higher doses, both prostanoids reduced enzyme release, suggesting some preservation or rapid re-establishment of epithelial cell continuity under these conditions. Studies utilizing the gastric chamber indicated that high doses of dmPGE2 (20-40 micrograms kg-1) reduced the changes in potential difference and potassium efflux following challenge with 50% ethanol, and accelerated the rate of recovery of these parameters. Furthermore, a reduced level of epithelial cell discontinuity was determined by histological techniques. Thus, prostanoids not only protect deeper mucosal cells from necrotic damage by local irritants, but may protect the surface cells at higher doses under some conditions, and may enhance the process of epithelial restitution.
D015064:16,16-Dimethylprostaglandin E2 / Q000494:pharmacology*; D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D015232:Dinoprostone; D000431:Ethanol / Q000037:antagonists & inhibitors; D005753:Gastric Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced / Q000517:prevention & control; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D011458:Prostaglandins E / Q000494:pharmacology*; D011459:Prostaglandins E, Synthetic / Q000494:pharmacology*; D051381:Rats
D011458:Prostaglandins E; D011459:Prostaglandins E, Synthetic; D000431:Ethanol; D007770:L-Lactate Dehydrogenase; D000135:Acid Phosphatase; D015232:Dinoprostone; D015064:16,16-Dimethylprostaglandin E2