光照应激对SD大鼠胃促性腺激素释放激素受体表达的影响

目的 观察光照应激状态下SD大鼠胃内促性腺激素释放激素受体（GnRHR）的表达变化。 方法 建立SD大鼠光照应激模型(共64只,实验组与对照组各32只)，24h持续光照，分别取光照1d、2d、3d、4d、1周、2周、3周、4周和相应对照组大鼠的胃，采用免疫组织化学、Western blotting和实时PCR法检测GnRHR在各时间段大鼠胃黏膜中的定位及蛋白和mRNA的表达变化。 结果 GnRHR阳性细胞广泛分布于大鼠胃底腺壁细胞中，在对照组和实验组中的定位无差异。实验组大鼠的GnRHR蛋白表达水平高于其相应的对照组。持续光照1～4周后，实验组与其对照组相比差异显著（P<0.05）；当持续光照2周时，GnRHR的表达至最高水平，与其对照组相比，差异极显著（P<0.01）。实验组大鼠胃GnRHR mRNA表达水平高于对照组，持续光照3～4周后，实验组大鼠胃GnRHR mRNA表达水平显著增加（P<0.05）。 结论 光照应激可以影响消化道内GnRHR的表达，提示GnRH通过其受体介导，对消化功能具有潜在的生理调节功能。GnRH除参与消化道正常生理功能外，可能还是一种参与应激反应的激素。

Effect of illumination stress on the expression of GnRH receptor in stomach of SD rat

Objective To study the expression of gonadotropin releasing hormone receptor (GnRH receptor) in the stomach of Sprague-Dawley rat exposed to light stress. Methods We established illumination stressed models that the rats were exposed to continuous light(totally 64 rats, 32 rats for experiment and control group, respectively). Then,stomachs were taken from the rats when the rats exposed to continuous light for 1 day, 2 days, 3 days, 4 days, 1 week, 2 weeks, 3 weeks, 4 weeks and their control groups, respectively.The localization and the expression of GnRHR and GnRHR mRNA in stomachs mucous membrane were detected using immunohistochemistry, Western blotting and real-time PCR. Results Immunoreactivity was displayed mostly in the parietal cells in gastric gland. There were not differences of this distribution in all groups of constant illumination and their control. The immunoreactive materials were distributed on membrane and in cytoplasm of all positive cells, but not in nuclei. The level of GnRHR in rats exposed to continuous illumination were higher from one week to four weeks compared with that in control(P<0.05), and the level of GnRHR reached the peak when rats were exposed to constant illumination for two weeks (P<0.01). The quantity of GnRH mRNA in rats exposed to continuous illumination were higher from three weeks to four weeks compared with that in control(P<0.05). Conclusion The expression of GnRHR in digestive tract was effected by illumination stress.GnRH might regulate digestive function by interaction with GnRHR, suggesting that GnRH may be acted as a hormone, not only responded to normal physiological function of digestive tract but also responded to stress activity.