针刺对去卵巢大鼠脑内胆碱乙酰转移酶基因表达的影响

Effect of acupuncture on the expression of choline acetyltransferase mRNA in the brain of ovarietomized rats

本工作旨在探讨雌激素对脑内乙酰胆碱生成的影响和电针刺激“足三里”穴对去卵巢大鼠脑内乙酰胆碱生成的调整作用。实验选用成年Wistar雌性大鼠,将动物分为正常对照组(INT)、去卵巢组(OVX)和去卵巢针刺组(OVX+AC)。用放射免疫分析方法测定血中雌二醇含量,采用RT-PCR方法获得大鼠脑内胆碱乙酰转移酶(ChAT)mRNA的逆转录表达产物——cDNA,用琼脂糖凝胶电泳方法检测,并通过原位杂交方法观察海马ChAT mRNA阳性神经元的表达,然后用计算机图像分析系统进行统计分析。实验结果显示:去卵巢组大鼠体内雌激素水平明显降低,脑内ChAT mRNA的RT-PCR产物和海马ChAT mRNA阳性表达产物的平均面积、平均积分光度值均明显减少,与对照组和针刺组比较有显著性差异;去卵巢针刺“足三里”穴组与去卵巢组相比,大鼠血中雌激素水平明显升高,脑内ChAT mRNA RT-PCR产物明显增多,海马的ChAT mRNA表达阳性神经元增多。以上结果提示:脑内ChAT基因表达与体内雌激素水平有密切关系,去卵巢后针刺“足三里”穴对ChAT的调节作用可能是针刺增强脑内乙酰胆碱含量的机制之一。

The purpose of the present study was to investigate the mechanism of the effect of estrogen on the production of acetylcholine in the brain and to study the regulatory role of acupuncture of Zusanli acupoint in acetylcholine production in the brain of ovariectomized rats. Experimental female Wistar rats were divided into three groups: intact group (INT), ovariectomized group (OVX), and ovariectomy and acupuncture group (OVX+AC). Radioimmunoassay (RIA) was used to measure the estrogen content in plasma. The mRNA expression of choline-acetyltransferase (ChAT) and glyceraldehyde phosphate dehydrogenase (GAPDH) in the brain of rats was measured by the RT-PCR technique and was tested by the method of agarose gel electrophoresis. The ChAT mRNA positive neurons in the hippocampus were observed by using in situ hybridization and the results were processed with a computerized image analysis system. The results are as follows. Compared with the control animals, the plasma estrogen level was significantly lowered in ovariectomized animals. However, the plasma estrogen level was higher in the OVX+AC group than that of the OVX group. The ChAT mRNA expression level of OVX+AC group was higher than that of the OVX group. The area and integral optical density of the ChAT mRNA positive neurons in the hippocampus increased more obviously in OVX+AC group than in the OVX group. The experimental results observed indicate that the expression of ChAT gene in the brain is possibly related to the estrogen level in the body. The expression of ChAT gene in the brain of the ovarietomized rat can be regulated by acupuncture of Zusanli acupoint and it may be one of the mechanisms that acupuncture increases acetylcholine content in the brain.