Inhibitory effect with antisense mitogen-activated protein kinase oligodeoxynucleotide against cerebral vasospasm in rats.

BACKGROUND AND PURPOSE Mitogen-activated protein kinase (MAPK) may be associated with the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). This study aimed to clarify the role of MAPK expression and activation during cerebral vasospasm and to evaluate the therapeutic effect on cerebral vasospasm using an antisense MAPK oligodeoxynucleotide (ODN). METHODS Antisense MAPK, sense MAPK, or scrambled ODN was injected into the rats intracisternally. We used a single-hemorrhage experimental SAH model to assess vasospasm in the basilar arteries at 30 minutes, 1 day, and 2 days after SAH by cross-sectional area measurement and other histological parameters. Immunohistochemistry and Western blot analysis were used to quantify MAPK expression and activation. In addition, a double-hemorrhage rat SAH model was used to test the effect of post-SAH treatment with antisense MAPK ODN. RESULTS Antisense MAPK therapy significantly inhibited cerebral vasospasm when compared with sense MAPK or scrambled ODN treatment on day 2. The immunohistochemistry and Western blotting performed in the basilar artery of rats that received antisense MAPK ODN demonstrated inhibition of MAPK and phosphorylated MAPK on day 2. In post-SAH treatment study, antisense ODN reduced MAPK and phosphorylated MAPK in the basilar artery and attenuated cerebral vasospasm. CONCLUSIONS MAPK activation, but not expression, might be implicated with sustained smooth muscle contraction during cerebral vasospasm after SAH. This study suggests that antisense MAPK ODN strategy is an effective treatment against cerebral vasospasm.