[The impact of different duration of EA-pretreatment on expression of MMP-9 and VEGF in blood-brain barrier in rats with cerebral ischemia-reperfusion injury].

OBJECTIVE

To observe the impact of preconditioning of EA stimulation of "Baihui" (GV 20) and "Shuigou" (GV 26) in different duration on expression of matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGF) in blood-brain barrier (BBB) tissues in rats with cerebral ischemia-reperfusion injury (CI/RI).

METHODS

Sixty-four male SD rats were randomly allocated to sham-operation (sham), model, EA-pretreatment 7 days (pre-t-7 d) and EA-pre-t-15 d groups (16 rats/group, 8 rats for immunohistochemistry and 8 for RT-PCR). The CI/RI model was established by occlusion of the middle cerebral artery for 90 min and reperfusion. EA (2 Hz/15 Hz, 1 mA) was applied to GV 20 and GV 26 for 30 min, once daily for 7 days and 15 days respectively before modeling. Immunohistochemical staining and fluorescence quantitative RT-PCR were employed to detect the expression of MMP-9 protein, MMP-9 mRNA and VEGF mRNA in the BBB tissues (choroid plexus).

RESULTS

Compared with the sham group, the number of MMP-9 immuno-reaction positive cells, and the expression of MMP-9 mRNA and VEGF mRNA in the model group were significantly increased (P<0.001), while compared with the model group, the number of MMP-9 positive cells, and expression levels of MMP-9 mRNA and VEGF mRNA in the EA-pre-t-7 d and EA-pre-t-15 d groups were significantly reduced (P<0.01), and the effects of EA-pre-t-15 d were markedly superior to those of EA-pre-t-7 d (P<0.01, P<0.05).

CONCLUSION

EA-pretreatment of GV 20 and GV 26 can effectively restrain CI/RI-induced increase of expression of MMP-9 protein, MMP-9 mRNA and VEGF mRNA in blood-brain barrier in CI/RI rats, which may contribute to its protective effect of ischemic cerebral tissue. Longer EA-pretreatment is relatively better.