The Concurrent Administration of Dexamethasone and Aldosterone Effectively Mitigates the Pronounced Pro-ulcerogenic Effect of Dexamethasone on the Gastric Mucosa in Rats
Authors: Filaretova Ludmila , Podvigina Tatiana , Komkova Olga , Yarushkina Natalia 
Published: May 2024

We previously established that the effect of dexamethasone (Dex) on the gastric ulceration is time dependent. Administering Dex 1 hour before an ulcerogenic stimulus provides gastroprotection, but extending the interval to 24 hours transforms its effect into a pro-ulcerogenic one. The prolonged maintenance of blood glucose levels induced by Dex, accompanied by catabolic effects, may, in part, account for its pro-ulcerogenic nature (Filaretova et., Inflammopharmacology 2009). Given the evidence that Dex primarily binds to glucocorticoid receptors (GRs), we hypothesized that Dex-induced imbalance in the activation of GRs and mineralocorticoid receptors (MRs) could contribute to the pro-ulcerogenic effect of Dex. We partly confirmed this (Filaretova and Sudalina, FASEB J. 2019). To further validate this hypothesis, we conducted a study to determine whether correcting the imbalance in the activation of GRs and the MRs, induced by Dex, through co-administering Dex with the MR agonist aldosterone (Aldo), can mitigate the pro-ulcerogenic effect of Dex. The effects of separate and combined administration of Dex and Aldo at a dose of 1 mg/kg (i.p.) 1 hour and 24 hours before the onset of ulcerogenic stimulus on the gastric erosions was evaluated in rats. Gastric injury was induced by indomethacin (IM, 35 mg/kg, sc) in preliminary fasted rats. Four hours after IM administration, the rats were decapitated, the stomachs were removed to estimate the erosion area; the adrenal glands, thymus and spleen were remove to estimate their weight, and trunk blood was collected to test the corticosterone and glucose levels. We confirmed the gastroprotective effect of Dex administered 1 hour and the pronounced pro-ulcerogenic effect of Dex administered 24 hours before IM. Aldo itself, administered 1 hour before IM had no effect on the gastric erosions, however, when administered 24 hours before IM, it led to a pro-ulcerogenic effect of IM, but much less pronounced comparing with that of Dex. Co-administration Dex and Aldo 1 hour before IM resulted in the gastroprotection similar to that of Dex alone. Co-administration Dex and Aldo 24 hours before IM effectively mitigates the pronounced pro-ulcerogenic effect of dexamethasone on the gastric mucosa. Dex administration resulted in a sharp decrease in the blood corticosterone level both when administered 1 hour and 24 hours before IM, however, the corticosterone levels in 24 hours were significantly lower than in 1 hour. Aldo itself did not lead to a significant decrease the corticosterone levels neither after 1 hour nor after 24 hours. We confirmed our previous results that Dex administration both 1 hour and 24 hours before IM leads to an increase in blood glucose levels. Administration of Aldo alone did change glucose levels. The effect of the combined administration of Dex and Aldo on glucose levels did not differ from that of Dex alone. 24 hours after Dex administration alone or co-administration Dex with Aldo, pronounced catabolic effects appeared: a decrease in the relative weight of the adrenal glands, thymus and spleen. In conclusion, the concurrent administration of Dex and Aldo effectively mitigates the pronounced pro-ulcerogenic effect of Dex on the gastric mucosa in rats. The results further confirmed our hypothesis. State Program 47 SP “Scientific and Technological Development of the Russian Federation” (2019-2030), 0134-2019-0001. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.