Electroacupuncture: a new approach to open the blood-brain barrier in rats recovering from middle cerebral artery occlusion.

OBJECTIVE: To examine for an opening effect on the blood-brain barrier (BBB) in intact rats and rats with experimental ischaemia-reperfusion (I/R) during the recovery period after various electroacupuncture (EA) treatments with different time courses, and to determine whether there is a time-dependent effect. An additional objective was to determine whether this method could induce the penetration of nerve growth factor (NGF) through the BBB. METHODS: A middle cerebral artery occlusion (MCAO) model was first established. We chose different stimulation time courses and observed the effects of EA treatment (100 Hz frequency; 2 mA intensity) at GV20 and GV26 on the BBB in rats recovering from MCAO 3 weeks after modelling. The rats were injected with 2% Evans blue (EB) saline. The brain water content was measured using a wet/dry weighing method. The degree of penetration of EB was detected using spectrophotometry and laser confocal microscopy. The rats were then injected with NGF, and the concentration of NGF in the brain tissues was measured using ELISA. RESULTS: The increase in the BBB permeability was most notable following the 8 min EA stimulation (P<0.05), which may be advantageous for the targeted delivery of drugs (such as NGF) into the brain. Additionally, this effect did not appear to cause brain oedema (P>0.05) in healthy or MCAO rats. CONCLUSIONS: EA treatment for a certain stimulation time at GV20 and GV26 in MCAO rats can increase BBB permeability.

[Effect of Acupuncture at "Taichong"(LR 3) and "Neiguan"(PC 6) on Blood Pressure and Contents of Aspartic Acid and Glutamic Acid in the Rostral Ventrolateral Medulla in Spontaneous Hypertension Rats].

OBJECTIVE: To explore the potential mechanism of acupuncture stimulation of "Taichong" (LR 3) and "Neiguan" (PC 6) in spontaneous hypertension rats (SHR) by investigating its effects on blood pressure and contents of aspartic acid(Asp) and glutamic acid (Glu) in the rostral ventrolateral medulla (RVLM) region. METHODS: A total of 75 SHR were randomized into model group, Taichong (LR 3) group, Neiguan (PC 6) group, LR 3+non-acupoint group and LR 3 + PC 6 group (n=15 rats in each group), and 15 Wistar rats of the same age were used as the normal control group. The filiform needles were inserted into the abovementioned acupoints and non-acupoint, twirled for a while and then retained for 30 min. The treatment was conducted once per day, 15 times in total. The rats' tail blood pressure was examined on day 1, 3, 7 and 15 after acupuncture treatment by using a non-invasive blood pressure monitor. At the end of experiment, the contents of Asp and Glu in the RVLM were detected by high-performance liquid chromatography with UV technique. RESULTS: On day 1, 3, 7 and 15 after the acupuncture treatment, the raised systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MBP) of PC 6, LR 3, LR 3 + non-acupoint and LR 3 + PC 6 groups were all decreased significantly compared with the model group (P<0.05). On day 15, the effect of the LR 3 + PC 6 group was significantly superior to that of the LR 3, PC 6, and LR 3 + non-acupoint groups in reducing the levels of SBP, DBP, and MBP (P<0.05).Compared with the normal control group, the contents of Asp and Glu in RVLM were significantly higher in the model group (P<0.05). After acupuncture intervention, both Asp and Glu levels in the PC 6, LR 3, LR 3 + non-acupoint, and LR 3 + PC 6 groups were markedly lower in comparison with the model group (P<0.05), and those of the LR 3 + PC 6 group were notably lower than those in the LR 3 and PC 6 groups (P<0.05). CONCLUSIONS: Acupuncture stimulation of PC 6, LR 3, LR 3 + non-acupoint and LR 3 + PC 6 (in particular) is effective in lowering blood pressure in spontaneous hypertension rats, which may be associated with its effects in lowering Asp and Glu contents in RVLM.