Corticosteroids induce the differential expression of TGFβ isoforms, receptors and signaling in the gastric mucosa of suckling rats

Glucocorticoids inhibit the cell proliferation in the gastric epithelium, and induce differentiation, migration and death. The mechanism by which these effects are triggered and controlled is still discussed and can involve the transcription and activation of transforming growth factor beta (TGFβ). The present study was conducted to evaluate the effect of hydrocortisone short-term treatment on tissue level and distribution of TGFβ isoforms, receptors and signaling through Smad2/3. To achieve that, 18-day-old rats were injected with hydrocortisone (50 mg/Kg b.wt.) for 0, 1 and 3 h. The stomachs were collected and processed for immunohistochemistry and western blotting. We observed that the treatment for 3 h increased the number of labeled epithelial cells for TGFβ1 (p < 0.05), decreased the distribution of TGFβ2 (p < 0.05) and did not alter TGFβ3, TβRI and TβRII status. The levels of TGFβ1 and receptors were checked by western blotting and results corroborate the immunodetection. We also found that phosphorylation of Smad2/3 into Smad2P increased after 3 h (p < 0.05), indicating that the high level TGFβ1 was active on the cells. We suggest that glucocorticoids differentially regulate the expression of TGFβ isoforms, receptors and signaling, and so TGFβ1 might be involved in the inhibitory pathway triggered by the hormone.