Objective To observe the effect of electroacupuncture(EA) combined with gavage of borneol on the permeability and ultrastructure of the blood-brain barrier(BBB) in mice

so as to reveal its mechanism underlying improving permeability of BBB.Methods For assaying Evans blue(EB) content in the brain

60 Kunming mice were evenly divided into control

EA

borneol(0.2 g/kg

borneol-0.2)

borneol(0.4 g/kg

borneol-0.4)

borneol(0.2 g/kg

borneol-0.2)+EA and borneol(0.4 g/kg

borneol-0.4)+EA groups.For determination of P-glycoprotein [P-gp

a member of the superfamily of ATP-binding cassette(ABC) transporters which transport various molecules across extra-and intra-cellular membranes] function and the ultrastructure of BBB

other 84 mice were randomized into control

borneol-0.2

borneol-0.4

borneol-0.2+EA

borneol-0.4+EA and verapamil groups(n=10 for P-gp function analysis

and n=2 for electron microscopic observation).EA(2 Hz

1 mA) was applied to "Baihui"(GV 20) and "Yamen"(GV 15) for 20 min

once daily for 14 days.EB(2.5%

0.2 mL/kg) and rhodamine(Rh)123(0.2 mg/kg) were injected intravenously first through the tail vein

and their contents in the brain and Rh 123 in the plasma were detected after EA by using an ultraviolet fluorescence microplate reader.At the same time

the permeation index(Kp) was calculated by the ratio of Rh 123brain/Rh 123blood.Results Compared with the control group

the cerebral EB and Rh 123 contents and Kp of BBB in the EA

borneol-0.2

borneol-0.4

borneol-0.2+EA

borneol-0.4+EA and verapamil groups were increased significantly(P<0.05

P<0.01).The cerebral EB content was significantly higher in the borneol-0.2+EA group than in the borneol-0.2 group(P<0.05)

suggesting a synergistic effect of EA and borneol.No significant differences were found among the EA

borneol-0.2 and borneol-0.4 groups in cerebral EB levels

among the control

EA

borneol-0.2

borneol-0.4

borneol-0.2+EA

borneol-0.4+EA and verapamil groups in plasma Rh 123 contents

and among the EA

borneol-0.2

borneol-0.4

borneol-0.2+EA

borneol-0.4+EA and verapamil groups in cerebral Rh 123 contents and Kp of BBB(P>0.05).Results of the electron transmission microscope showed that the compact degree of the tight junction of BBB was decreased in the borneol-0.2

borneol-0.4

borneol-0.2+EA

borneol-0.4+EA groups but not in the EA group.Conclusion EA and gavage of borneol treatments may enhance the permeability of BBB for EB and Rh 123 and have a certain synergistic effect in mice.The effect of borneol may be closely with the inhibition of P-glycoprotein and the decrease of tight junction of BBB while the effect of EA treatment is probably related to the inhibition of P-glycoprotein only.