In previous studies [Gut 35 (1994) 896-904], we demonstrated that
antacid talcid (TAL) accelerates
gastric ulcer healing and provides better quality of mucosal restoration within the
scar than the
omeprazole (OME). However, the mechanisms of TAL-induced
ulcer healing are not clear. Since
growth factors promote cell proliferation, re-epithelization, angiogenesis and
ulcer healing, we studied whether TAL and/or OME affect expression of
epidermal growth factor (
EGF) and its
receptors (EGF-R) in both normal and ulcerated gastric mucosae. Rats with or without
acetic acid-induced
gastric ulcers (n = 64) received i.g. twice daily 1 mL of either: A) placebo (PLA); B) TAL 100 mg; or C) OME 50 mg x kg(-1) for 14 d. Studies of gastric specimens: 1)
ulcer size; 2) quantitative histology; 3) expression of
EGF mRNAs was determined by RT/PCR; 4) gastric sections were immunostained with
antibodies against
EGF and its receptors. In non-ulcerated gastric mucosa of placebo or
omeprazole treated group,
EGF expression was minimal, while
EGF-R was localized to few cells in the mucosal proliferative zone. Gastric ulceration triggered overexpression of
EGF and its receptor in epithelial cells of the
ulcer margin and
scar. In ulcerated gastric mucosa TAL treatment significantly enhanced (versus PLA and
omeprazole) expression of
EGF and
EGF-R. OME treatment reduced expression of
EGF in ulcerated mucosa by 55 +/- 2% (P < 0.01). It is concluded that: 1) treatment with TAL activates genes for
EGF and its receptor in normal and ulcerated gastric mucosae; 2) since
EGF promotes growth of epithelial cells and their proliferation and migration, the above actions of TAL provide the mechanism for its
ulcer healing action and improved (versus OME) quality of mucosal restoration.