【作者】 陈颖；

【导师】 徐珞；

【作者基本信息】 青岛大学 ， 病理生理学， 2017， 硕士

【摘要】 目的:探讨Orexins对小鼠摄食和能量代谢的影响及潜在机制。方法:采用免疫组织化学方法,观察orexin-A免疫阳性神经元在下丘脑腹外侧区(LHA)的表达。第三脑室置管,观察第三脑室注射不同剂量orexin-A(1.5nmol,3.5nmol或15 nmol)或orexin-B(1.5,3.5或15 nmol)对小鼠0-2h和0-4h摄食量的影响,以及采用ELISA方法,观察第三脑室注射不同剂量orexin-A(1.5nmol,3.5nmol或15 nmol)或orexin-B(1.5,3.5或15 nmol)对小鼠肝脏线粒体柠檬酸合酶活性的影响。另外通过置管向第三脑室注射orexin-A,应用代谢测量装置,观察小鼠在光照、黑暗以及禁食条件下呼吸熵(RQ=二氧化碳生成量VCO2与耗氧量VO2的比率)和代谢率的变化。结果:免疫组织化学结果显示,下丘脑外侧区有Orexin-A免疫阳性神经元的表达。摄食研究结果显示,与第三脑室注射NS或3.5 nmol orexin-A相比,第三脑室注射低剂量(1.5 nmol)或高剂量(15 nmol)orexin-A,在注射后0-2小时和0-4小时,小鼠摄食量均显著增加(P<0.05);但第三脑室注射3.5 nmol orexin-A,小鼠摄食量无显著改变(P>0.05)。第三脑室注射任何剂量的orexin-B对小鼠摄食量均无显著影响(P>0.05)。为了进一步研究orexins对机体主要代谢器官肝脏线粒体功能的影响,我们还观察了第三脑室注射orexin-A或orexin-B对肝脏线粒体中柠檬酸合酶活性的影响。与第三脑室注射低剂量(1.5 nmol)orexin-A组相比,第三脑室注射中剂量(3.5nmol)或高剂量(15 nmol)orexin-A,小鼠肝脏线粒体柠檬酸合酶活性显著增强,且呈显著量效依赖关系(P<0.05~0.01)。第三脑室注射低剂量(1.5 nmol)、中剂量(3.5 nmol)或高剂量(15 nmol)orexin-B,小鼠肝脏线粒体柠檬酸合酶活性均无显著改变(P>0.05)。因为进入光照周期3小时后(9:00 Am)第三脑室注射3.5 nmol orexin-A并没有显著增加小鼠摄食量(P>0.05,图1),所以我们选择了第三脑室注射3.5 nmol orexin-A观察其对能量代谢的影响。本研究发现,在光照条件下,与NS组相比,第三脑室注射3.5 nmol orexin-A,小鼠呼吸熵显著降低(P<0.05),代谢率显著增加(P<0.05)。给禁食24h的小鼠第三脑室注射3.5 nmolorexin-A,小鼠在注药后的第4和第5小时,呼吸熵(P<0.05)和代谢率(P<0.05)均有短暂显著升高。结论:Orexin-A可促进小鼠摄食,该调控作用与其作用的受体特异性(OXR1,OXR2)有关;orexin-A可促进能量代谢,该效应与昼夜时相相关。更多还原

【Abstract】 Objective:To investigate the effects of orexins on feeding and energy metabolism in mice.Methods:The distribution of orexin positive neurons in the brain was analyzed by immunohistochemistry.The effects of different doses of orexin-A(1.5nmol,3.5nmol or 15 nmol)or orexin-B(1.5,3.5 or 15 nmol)on the food intake during 0-2h and 0-4h were observed via Third ventricle catheterization.ELISA method was used to observe the effects of different doses of orexin-A(1.5nmol,3.5nmol or 15 nmol)or orexin-B(1.5,3.5 or 15 nmol)on the activity of citrate synthase in the liver mitochondria of mice.In addition to the third ventricle injection of orexin-A through catheter,application of metabolic measurement device were observed in light and dark and under fasting conditions respiratory quotient(RQ= VCO2 production of carbon dioxide and oxygen consumption VO2 ratio)and the changes of metabolic rate.Results: Immunohistochemical analysis showed that Orexin-A immunoreactive neurons were mainly expressed in the lateral hypothalamic area(LHA)in the central nervous system.The feeding results show that compared with the NS group and orexin-A 3.5nmol group,after injection of low dose(1.5nmol)or high dose(15nmol)orexin-A into the third ventricle 0-2 hours and 0-4 hours,food intake increased significantly(P<0.05),and compared with the NS group,the third ventr icle injection of 3.5nmol orexin-A,the food intake no significant change(P>0.05).The third ventricle injection of any dose of orexin-B had no significant influence on the food intake of mice(P>0.05).In order to further investigate the effect of orexin on mitochondrial function of the major metabolic organ,the effects of third ventricle injection of orexin-A and orexin-B on the activity of citrate synthase in liver mitochondria were examined.Compared withthe third ventricle were injected with low dose(1.5nmol),the third ventricle were injected withmiddle dose(3.5nmol)or high dose(15nmol)orexin-A could significantly increase the mitochondrial citrate synthase activity and(P<0.05)a significant dose dependent relationship(P<0.05~0.01).Compared with the NS group,the third ventricle injection of orexin-B did not cause the activity of the citrate synthase altered in the liver mitochondria(P>0.05).The effect of energy metabolism was observed after injection of 3.5nmol orexin-A into the third ventricle.The results showed that orexin-A could increase(P< 0.05)the metabolic rate by decreasing the respiratory quotient(P<0.05).In the dark cycle,orexin-A had no effect on RQ,but Orexin-A induced a more persistent increase in metabolic rate(P<0.05).In fasted mice,3.5nmol(orexin-A)was injected into the third ventricle,and its respiratory entropy(RQ)was transiently elevated and metabolic rate increased significantly(P > 0.05).Conclusion: Orexin-A can promote the feeding in mice,which is related to the receptor specific OXR2(OXR1),and orexin-A can promote energy metabolism,which is related to circadian rhythm更多还原