| Stress was non-specificity general reaction when environmental agent from exterior and interior stimulated organism.The homeostasis of organism will be damaged and the disease will be occur when the organism was stressed for longtime. Continuous illumination cause endocrine system confused especially pituitary-gonad axis which cause weight change and gonadal development,intensity and permanence of GnRH,LH secretion.In addition,there are influence of long photoperiod on amylase activity in the pancreas and small intestine in rats.Soldiers who were subjected to stimuli of war environment will be deprived of coping ability and will suffer from psychonosema.This stimuli is called combat stress reaction.This status developed to latter will result in post-traumatic stress disorder.In our present study,We established two stressed models included continuous illumination and predator threat.The expression of GnRH and GnRH receptor in digestive system of respective model were evaluated.The rat weight,the weight of testis and epididymis and sperm comparative counting were evaluated in the rats exposured to continuous light.Results indicated that,comparing with the control group,the rat weight and the weight of testis were higher in the rats exposured to continuous light,but there were not significant differences.The weight of epididymis was not difference with that in control.Sperm comparative counting were higher than that in control(P＜0.01),Immunohistochemistry showed that,GnRH and GnRH receptor in all groups,immunoreactivity were displayed in the gastric parietal cells and the epithelial cells of the gastric pits in stomaches.There were not differences of this distribution in both groups of constant illumination and their control.The immunoreactive materials were distributed in membrane and cytoplasm of all positive cells,but not in nuclei.Compared with that in control,the average gray scale of GnRH in rats exposured to continuous illumination were higher from two weeks to four weeks(P＜0.05)and reached the peak at two weeks.Western blotting showed that the number of GnRH receptor were higher than that in control.The significant difference was happened when SD rats were constant illumination one week(P＜0.05).The number of GnRH receptor were the highest when rats were exposured to constant illumination for two weeks(P＜0.01).From three weeks to four weeks,the number of GnRH receptor was decreased,but the number in rats exposured constant illumination was still higher than that in control.Real-time PCR showed that the quantity of GnRH and GnRH receptor mRNA increased when constant illumination time was prolonging,There were significant differences of GnRH mRNA and GnRH receptor mRNA in both groups when rats exposured in constant illumination for two weeks(P＜0.05)and for three weeks(P＜0.05) respectively.In Predator threat model,immunohistochemistry showed that GnRH receptor immunoreactivity were displayed in the gastric parietal cells and the epithelial cells of the gastric pits in stomaches of all group rats.The immunoreactive materials were distributed in membrane and cytoplasm of all positive cells,but not in nuclei. Meanwhile,Western blotting showed that the level of GnRHR expression inclined to decrease under acute stress,there were no significant differences between the acute stress and the control(P＞0.05).The number of GnRH receptor decreased significantly when rats were in chronic stress(P＜0.01).In small intestine of rats, immunohistochemistry showed that GnRH receptor immunoreactivity was displayed in the cells above mucous layer in small intestine of rats for all groups.The immunoreactive materials were distributed in membrane and cytoplasm of all positive cells,but not in nuclei.Western blotting showed that the level of GnRHR expression inclined to increase under acute stress,there were not significant differences between the acute stress and the control(P＞0.05).However,compared with the control group, the number of GnRH receptor increased significantly in chronic stress group(P ＜0.05).Conclusion:Digestive system have GnRH and GnRH receptor,the expression of GnRH and GnRH receptor in digestive tract were effected by stress.GnRH might regulate digestive function under stress by autocrine and paracrine. |
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