Objective: To determine the expression of pS(2) (a member of trefoil peptides) in gastric mucosal of rats undergone WRS, and to probe the role of pS(2) in adaptive cytoprotection.
Methods: Wistar rats were exposed to single or repeated WRS for 4 h every other day for up to 6 days. Gastric mucosal blood flow (GMBF) was measured by LDF-3 Flowmeter. The degree of the gastric mucosal lesions (UI) was evaluated grossly and histologically. The expression of pS(2) was determined by RT-PCR and immunohistochemistry.
Results: (1) WRS applied once produced numerous gastric mucosal erosions. UI gradually declined and GMBF restored on 3 d, 5 d after stress. UI was reduced to 20.8% and GMBF increased up to 94.5% of normal value. The expression of pS(2) was increased during the healing of stress-induced ulceration. The same results were observed by immunohistochemistry (0.50 +/- 0.13 vs 0.70 +/- 0.11, P < 0.01). (2) With repeated WRS, the adaptative cytoprotection against stress was developed. UI after four consecutive WRS was 22% of UI after one WRS. GMBF after four consecutive was 94.2% of normal value. Cell proliferation in the neck regions of gastric glands was activated. The expression of pS(2) was increased by using RT-PCR (0.37 +/- 0.02 vs 0.77 +/- 0.01, P < 0.01) and immunohistochemistry (0.55 +/- 0.04 vs 2.46 +/- 0.08, P < 0.01).
Conclusion: Increased expression of pS(2) could play an important role in adaptation of gastric mucose developed after repeated WRS.