[Effects of scalp acupuncture on expression of hippocampal MMP-9 in cerebral ischemia injury rats].

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.