禁食不同时段下丘脑穹窿周区orexin-A的表达

目的探讨禁食不同时段大鼠下丘脑穹窿周区orexin—A的表达及是否与摄食有关。方法观察禁食前后大鼠体重变化，采用免疫组织化学染色法观察禁食不同时段下丘脑穹窿周区orexin-A的表达变化，灰度值测量观察各组orexin—A的染色强度。结果大鼠体重随禁食时间的延长而逐渐降低，各组大鼠禁食前后体重变化有统计学差异（P〈O．01）；Orexin-A主要分布于下丘脑穹窿周区，禁食组orexin—A阳性神经元计数明显多于对照组（P〈O．05），但不同禁食组间orexin-A阳性神经元计数比较没有统计学差异（P〉O．05）；禁食48h组染色强度最深，与对照组和禁食24h、72h组有明显统计学差异（P〈0．05）。结论禁食可以促进orexin-A的表达，禁食48h应该是一种理想的促进orexin-A活化的刺激方式，orexin-A系统可能参与摄食及能量代谢的调节。

Expression of orexin-A at different fasting periods in the perifornical area of hypothalamus

Objective To explore the expression of orexin-A at different fasting periods in the perifor- nical hypothalamus and to see if orexin-A is involved in feeding. Methods We observed the changes in the body weight of rats before and after fasting, and observed the expression change of orexin-A and its stai- ning intensity at different fasting periods in the perifornical hypothalamus by using immunohistochemistry and gray value analysis, respectively. Results The body weight of rats gradually decreased with fasting time, the change of the body weight before and after fasting was statistically different in each group（P〈 0.01）; Orexin-A was mainly found in the perifornical hypothalamus, and the number of orexin-A positive cells in the fasting group was obviously more than in the control group（P〈0.05）, but was not significant- ly different among 3 fasting groups. Further analysis of gray value of immunopositive cells revealed that orexin-A in the 48 h fasting group was most strikingly immunostained compared with that of other groups （P〈0.05）. Conclusion Fasting may increase the expression of orexin-A, and fasting for 48 h should be an ideal stimulating pattern to promote orexin-A activation, Orexin-A system might be involved in feeding and the regulation of energy metabolism.