下丘脑中增食欲素在大鼠急性低血糖应激中的表达研究

Expression of Orexin in Acute Hypoglycemia in Rat Hypothalamus

目的研究急性葡萄糖水平的下降对大鼠下丘脑组织中增食欲素(Orexin)的调节作用。方法应用单次皮下注射胰岛素并伴(或不伴)禁食的方法,构建急性低血糖大鼠模型。检测外周血中葡萄糖和胰岛素水平的变化规律。采用原位杂交方法鉴定下丘脑组织中Orexin mRNA的定位表达。应用实时定量PCR和Western印迹杂交分析检测下丘脑组织中Orexin mRNA和蛋白质在急性低血糖应激状态下的表达改变。结果下丘脑神经元细胞核中有Orexin mRNA表达。在低血糖伴禁食应激状态下,大鼠下丘脑Orexin mRNA表达明显增加3倍,Orexin的蛋白质表达明显增加2.5倍,差异有统计学意义(P<0.05)。但在低血糖伴进食状态下,Orexin基因表达无明显改变。结论急性血糖的降低将在基因转录和翻译水平增强大鼠下丘脑中Orexin的表达,而摄食行为可以抑制此调控效应。

Objective To evaluate the effect of acute hypoglycemia on expression of Orexin in rat hypothalamus, Methods Acute hypoglycemia rat model was established by a single subcutaneous injection of insulin with （or without） feeding. The levels of glucose and insulin in rat serum were detected in vivo and the location of Orexin mRNA in rat hypothalamus was identified by situ hybridization. The expression of Orexin in rat hypothalamus tissue was examined by real-time PCR and Western blot analysis. Results The expression of Orexin mRNA was located in nucleus of hypothalamic neuron. The expressions of Orexin mRNA and its protein increased 3 and 2.5 times respectively in insulin-induced acute hypoglycemia rat without feeding, with statistical significant difference（P 〈 0.05 ）. However, the expression of Orexin didn＇t change in acute hypoglycemia rat with feeding. Conclusion Orexin in rat hypothalamus can be stimulated by acute hypoglycemia and this modulation can be inhibited by signals related to feeding.