Research On Correlation Between Fear Stress And Experimental Rats Asthma

Objectives:To study the effects of fear stress on experimental rats asthma so as to guide the clinical practice.Methods:1. Grouping and Model building:Thirty-two healthy male grown-up SD rats were divided into four groups by means of random number table:the control group (group A), the asthma group (group B), the fear stressed group (group C) and the fear stressed asthma group (group D). Rats sensitized with ovalbumin (OVA) via intraperitoneal injection were then exposed to OVA. Soak the rats into water to generate a feeling of fear stress.2. Symptoms related to asthma and general appearance of all rats during the experiment were observed. Airway peak pressure was measured with 4-lead graph system, the levels of interleukin-4 (IL-4) and glucocorticoid (GC) were detected by ELISA, and the histopathological changes of lung tissues were observed by HE staining.Results:1. Symptoms related to asthma and general appearance:Group B and group D both developed asthma, and symptoms related to asthma of group D were more serious than that of group B. During the late period of this expriment, the coat color of rats in both group B and D became dim, bluish discoloration of lips and ears occurred in rats of the both groups. In addition to those conditions, rats in group D still developed incontinence of feces and urine. Coat color of rats in group A was fine and no special behaviours showed in this group. Coat color of rats in group C was less dimmer than that of rats in group A, and few rats in group C develpoed dyspnea. Manic behaviors were discovered in the rats of group C and D after soaking into water. Food intake in rats of group B, C and D decreased at different levels during the expriment as compared with group A, amomg which, group D decreased most, group B less and group C least.2. Airway pressure:As compared with group A, airway pressure in the rats of group B and D was much higher (P<0.01), and group D was higher than group B (P<0.01), yet there was no statistically significant difference between group A and C (P>0.05).3. The levels of IL-4 and GC:Compared with group A, IL-4 level in the rats of group B, C and (?) was much higher (P<0.01) group B was higher than group C (P<0.01), group D was higher than group B (P <0.01); in comparison with group A, GC level in the rats of group B,C and D was much higher (P<0.01), group D increased significantly, group D was higher than group C (P<0.01), group C was higher than group B (P<0.01).4. The histopathological changes of lung tissues:Observed by HE staining under optical microscope. The epithelium cells of bronchia at different levels were integrate in the rats of group A, and inflammatory cells were not clearly visible; inflammatory cells were infiltrating bronchial tubes at different levels and pulmonary small vascular walls in the rats of group B, C and D, among them, group D was the most serious, and even lung consolidation was discovered around some bronchial tubes in the rats of group D.Conclusions:Fear stress aggravates the allergic airway responses and results in a higher level of airway peak pressure, which is probably produced by increasing the release of endogenous GC and suppressing the activation of Th2 cells, and thus increasing the synthesis of IL-4.