Objective To observe the effect of scalp-acupuncture on the expression of matrix metalloproteinase 9(MMP-9) in the endothelium of the microvessels in the hippocampal CA 3 area in local cerebral ischemia(CI) rats

so as to study its underlying mechanism in improving CI. Methods Eighty male Wistar rats were randomized into normal control(n=8)

sham-operation(n=8)

CI model(n=32)

and scalp-acupuncture(n=32) groups.The later two groups were further equally and respectively divided into 1

3

5 and 10 d subgroups.CI model was established by occlusion of the middle cerebral artery(MCAO)."Baihui"(GV 20) and "Qubin"(GB 7) were punctured with filiform needles and stimulated by twirling the needle at a frequency of about 200 revolutions/min for 1 min.The needles were retained for 30 min and re-manipulated once again every 10 min.The treatment was given once daily

continuously for 1

3

5 and 10 days respectively in different subgroups.MMP-9 immunoactivity of hippocampal CA 3 area was assayed by immunohistochemistry(SABC). Results Following CI

the CI rats' neural deficit scores in the model and scalp-acupuncture(treatment) groups had no apparent difference(P>0.05).After acupuncture

the neural deficit score in the treatment group decreased gradually

and was significantly lower than that in the 10 d subgroup of model group(P<0.05).Compared with the 1

3

5 and 10 d subgroups of control group

the total area and integral optical density(IOD) values of MMP-9 immunoactivity of hippocampal CA 3 area were all increased significantly in the corresponding 4 subgroups of model group(P<0.01).Compared with the 3

5 and 10 d subgroups of the model group

the total area and IOD values of MMP-9 immunoreaction positive products in the corresponding 3 subgroups of scalp-acupuncture group were decreased significantly(P<0.05

P<0.01).Conclusion Scalp-acupuncture can effectively down-regulate MMP-9 expression in the hippocampal CA 3 area in focal cerebral ischemia rats

which may contribute to its effect in improving the neural deficit.