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 cycle on the development of cold restraint-induced gastric lesions in single- and group-stressed female rats. Therefore, adult female Wistar rats, in different phases of the estrus cycle (proestrus, estrus, metestrus and diestrus), 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 between stressed female rats in different phases of the estrus cycle indicated that gastric pathology was significantly higher in estrus phase as compared to the other phases of the estrus cycle. The intensity of stress-induced gastric pathology was either not changed (estrus), moderately decreased (proestrus and metestrus) or highly decreased (diestrus) by increasing the number of concomitantly exposed rats to cold restraint. The vulnerability to cold restraint-induced stress ulcer rose as followed: proestrus < metestrus < diestrus < estrus. It could be concluded that female rats are more vulnerable to cold restraint-induced stress ulcer in estrus period and that in this phase, social interaction did not made any significant influence on the stress induced gastric lesions.