模拟失重降低大鼠血清和下颌下腺Ghrelin水平

目的观察模拟失重状态下大鼠血清和下颌下腺内Ghrelin表达的变化，为探讨航天失重环境下消化系统功能紊乱的机制提供实验依据。方法采用尾悬吊模拟失重模型，30只Sprague-Dawley大鼠随机分为4周悬吊组（n=15）和正常对照组（n=15），用酶免疫分析（EIA）法测定动物血清和下颌下腺组织中Ghrelin的浓度。结果与正常对照组比较，模拟失重组大鼠血清和下颌下腺组织中Ghrelin水平均显著降低【（7．14±1．65）μg／Lus（5．72±1．42）μg／L，P〈0．05；（8．36±1．87）μg／gVS（6．45±2．06）μgg，P〈0．01）1。结论模拟失重环境可致大鼠血清和下颌下腺组织中Ghrelin水平下降。Ghrelin可能参与模拟失重环境下消化系统功能紊乱的调节。

Simulated weightlessness decreases serum and submandibular gland ghrelin levels in rats

Objective To observe the alterations of ghrelin expression in serum and submandibular gland of rats following 4 weeks tail-suspension simulated weightlessness,and provide experimental evidence for studying the mechanism of spaceflight weightless enviroment on digestive system function disturbance.Methods By using tail-suspened simulated weightless model,thirty Sprague-Dawley rats were randomly divided into 4 weeks tail-suspension group(n=15) and in-phase normal control group(n=15).Localization and expression of ghrelin in rat submandibular gland were observed by immunohistochemistry,and enzyme-immuno-assay(EIA) was used to detect ghrelin concentration in serum and submandibular gland of rats in each group.Results Ghrelin immunoreactive cells were mainly distributed in the cytoplasm of striated and granular convoluted ducts,as well as in partial serous acini of submandibular glands,with the highest staining intensity for ghrelin in granular convoluted ducts.The intensity of ghrelin immunostaining in striated and granular convoluted ducts of submandibular gland in tail-suspened group were lower than those of in normal control group.The concentration of ghrelin both in serum and submandibular gland were decreased significantly compared with normal control group (7.14±1.65)μg/L vs(5.72±1.42)μg/L,P < 0.05;(8.36±1.87)μg/g vs(6.45±2.06)μg/g,P < 0.01)].Conclusion Ghrelin is expressed in the epithelial cells of the ducts and serous acini of submandibular glands;and simulated weightless environment can reduce the level of ghrelin in serum and submandibular gland.These results suggest that ghrelin might be involved in the regulation of digestive system function in simulated weightless environment.