Abstract

The present study compares gene expression and infarct area in a mouse model of embolic stroke after thrombolysis with t-PA and SMTP-7. Embolic occlusion was induced by transfer of acetic acid-induced embolus into the brain. t-PA or SMTP-7 was administered 3 h after embolization. Changes in gene expression were evaluated using microarray and RT-PCR analysis. To determine the involvement of reactive oxygen species in the response to t-PA, the free radical scavenger edaravone was infused immediately before t-PA administration. The expressions of 459 genes involved in the inflammatory response, cell-to-cell signaling, cell movement, and inflammatory disease were altered by embolic occlusion. Twenty-two of those genes were upregulated after t-PA but not SMTP-7 administration. Differences between the t-PA- and SMTP-7-treated groups in the expression of genes including the proinflammatory genes Il6, Stat3, S100a8, and Mmp9 were confirmed with RT-PCR. Edaravone ameliorated the overexpression of these genes. Our data demonstrate differences in gene expression following treatment with SMTP-7 or t-PA that likely explain the difference in therapeutic time windows of the two drugs. ROS are involved in the overexpression of proinflammatory genes. The wide therapeutic time window may be achieved through an anti-oxidative effect and inhibition of proinflammatory gene overexpression.

Highlights

  • Thrombolysis therapy using tissue plasminogen activator (t-PA) is highly effective in the early stages of ischemic stroke

  • cerebral blood flow (CBF) at 24 h after embolization recovered to about 70% of the initial value after administration of either agent; no significant difference in CBF was observed between the t-PA and Stachybotrys microspora triprenyl phenol-7 (SMTP-7) groups

  • Edaravone reduced cerebral infarction and prevented proinflammatory gene overexpression To investigate whether the upregulation of Il6, Stat3, S100a8, and Mmp9 expression after ischemia/reperfusion is related to the production of reactive oxygen species (ROS), we examined the cerebral infarct area and expression of the four genes after combined administration of edaravone and t-PA

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Summary

Introduction

Thrombolysis therapy using tissue plasminogen activator (t-PA) is highly effective in the early stages of ischemic stroke. The risk of hemorrhagic complications beyond 3 h following ischemia significantly increase due to breakdown of blood–brain barrier [2]. An alternative strategy is needed to extend the therapeutic time window, which would minimize damage from ischemia/reperfusion injury [4]. Stachybotrys microspora triprenyl phenol-7 (SMTP-7) has a wide therapeutic time window and results in minimal intracerebral hemorrhage compared with t-PA (5 – 7). Model mice given SMTP-7 show relatively mild rolling and attachment of leukocytes to the vascular wall following thrombolytic reperfusion [8]. These properties of SMTP-7 make it an excellent therapeutic agent for cerebral infarction in this embolic stroke model

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