| Background Stress is a pathogenic complex of neural, endocrinal and immune response to both inner and outer stimuli that surpass the physiological threshold. Strong psychophysical stress or longtime chronic psychophysical stress does great harm to human health, which causes emotional abnormalities, excitatory sympathetic neural activity, gastrointestinal injury, low response of immunity and abnormality of neuroendocrine function as well. With the development of modern techniques, the occurrence of serious stress-induced diseases, as stress ulcer for example, is dropping stably. However, the occurrence of functional diseases including irritable bowel disease (IBS) is rising rapidly, which was ascribed to psychological diseases by more and more people. Stressing incidence has been considered one of the most important contributors to those functional diseases. Modern medical pattern is the integrity of biological, psychological and social aspects So far, no standard animal model has been developed, which limits the research in the effect of psychological factor on stress. Therefore, development of a psychological animal stress model is not only very helpful for management of psychological diseases, but also provides essential information for prevention or relief of stress. In middle seventies, Bartrop et al initiated a prospective study on stress-induced immune response in population. Since then, the relationship between stress and immunefunction have been studied widely and deeply. According to those studies, immune functions of the subjects under different stress status were found changed, to some extent, in different aspects. Generally speaking, immune functions, especially cellular immunity, were injured by serious stress. Yet in stress, little has been known about the corresponding changes in common mucosal immune system. Therefore, it is essential to observe the changes of immune molecules and cells.AIMS 1. To establish psychophysical stress model of rats by using noise together with water avoidance stimuli; 2. To observe the effect of psychophysical factors in stress on gastric mucosal injury, gut motility and mucosal immune function based on this model.METHODS Rats were randomLy divided into four groups as blank control, water avoidance, noise exposure and noise plus water avoidance (complex stimuli). In the noise and complex groups, three subgroups were divided according to the different stimulatory intensity. No stimuli were given in control group; in water avoidance group, rats were limited on a plate surrounded by water; noise was given by three different intensity (60, 80, lOOdB, respectively). Experimental contents include the observation of behavioral indexes, detection of plasmic concentration of adrenocorticotropic hormone and corticosterone, and serai IgG and secretary IgA as well. Experimental data were recorded as mean ?standard error and analyzed by / test.RESULTS Mean characteristic behavioral indexes such as startling, rearing, washing-face and grooming of the three experimental groups (water avoidance test, noise exposure and complex stimuli) were higher than those of the control group. It was the same with open-field reactions and plasmicACTH and CORT levels. Differences between experimental groups were of statistical significance except that between the water avoidance group and control (P<0.05). But for grooming, significant differences were found in the four behavioral indexes between the complex stimuli group C and respective noise exposure group C, while behavioral indexes of other experimental groups being significantly different. As for rearing times and open-field reactions, no significant difference was found between the complex stimuli group B, C and respective noise exposure groups, while indexes of other groups varied significantly. ACTH and CORT levels in the complex stimuli group were higher than noise exposure group (P<0.05). CRF-mRNA was detected in the hypothalamus in the water-avoidance group, noise exposure group and complex stimuli group, but...
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