Estrus cycle and gastric lesions in individual- and group-stressed female rats

The aim of the present study was to analyze the influence of the estrus cyc le on the development of cold restraint-induced gastric lesions in single- and group-stressed female rats. Therefore, adult female Wistar rats, in dif ferent phases of the estrus cycle (proestrus, estrus, metestrus and diestru s), were restrained individually or in groups (two, three, six or nine rats ) and exposed to a temperature of 4 degrees C for 2 h. The comparison betwe en stressed female rats in different phases of the estrus cycle indicated t hat gastric pathology was significantly higher in estrus phase as compared to the other phases of the estrus cycle. The intensity of stress-induced ga stric pathology was either not changed (estrus), moderately decreased (proe strus and metestrus) or highly decreased (diestrus) by increasing the numbe r of concomitantly exposed rats to cold restraint. The vulnerability to col d restraint-induced stress ulcer rose as followed: proestrus < metestrus ( diestrus < estrus. It could be concluded that female rats are more vulnerab le to cold restraint-induced stress ulcer in estrus period and that in this phase, social interaction did not made any significant influence on the st ress induced gastric lesions. (C) 1999 Elsevier Science B.V. All rights res erved.