[Effect of Electroacupuncture at Different Acupoints on Expression of NGF and TrkA in Cerebral Cortex in Rats with Myocardial Ischemia].

OBJECTIVE: To compare the therapeutic effect of electroacupuncture (EA) of "Shenmen" (HT 7, Yuan point of the Heart Meridian), "Zhizheng" (SI 7, Luo point of the Small Intestine Meridian) and "Xinshu" (BL15, Back- shu point) on the expression of nerve growth factor (NGF) and its receptor, tyrosine kinase A (TrkA) in the cerebral cortex of myocardial ischemia (MI) rats.

METHODS: A total of 70 male SD rats were randomized into sham operation (sham, n =10), model, HT 7, SI 7, and BL15 groups ( n =15 in each of the latter 4 groups). The MI model was established by ligation of the anterior descending branch of the left coronary artery. EA (1 mA, 2 Hz) was respectively applied to HT 7, SI 7 and BL15 for 15 min, once per day for 1 week. Immunohistochemistry and real-time fluorescent quantitative PCR were used to detect the expression of NGF and TrkA proteins and genes in the cerebral cortex.

RESULTS: Compared with the sham group, no significant changes were found in the number of NGF immune-reaction (IR)-positive and TrkA IR-positive cells, and the expression levels of NGF mRNA and TrkA mRNA in the model group ( P >0.05). After EA intervention, the number of NGF and TrkA IR-positive cells and the expression of NGF mRNA and TrkA mRNA in each of the 3 EA groups were significantly increased relevant to the model group ( P <0.01, P <0.05). The effect of EA at BL 15 was significantly superior to that of EA at HT 7 and SI 7 in increasing the number of NGF and TrkA positive cells and up-regulating the expression of their mRNAs ( P <0.01, P <0.05).

CONCLUSION: EA at HT 7, SI 7 and BL 15 can increase the levels of expression of NGF and TrkA proteins and mRNAs in the cerebral cortex of subacute MI rats and the effects of EA-BL 15 are obviously superior to those of EA-HT 7 and EA-SI 7, suggesting a relative specificity of the effect of EA at different acupoints.