Article
Treatment of cerebral vasospasm after experimental subarachnoid hemorrhage using intracisternal heme-oxygenase-1(HO-1) fused to a arginine protein transporter domain
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Published: | September 16, 2010 |
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Objective: Heme-oxygenase-1(HO-1) is a 32 kDa enzyme involved in heme-catabolism and cleaves heme to form biliverdin and carbon monoxide (CO). HO-1 is said to reduce the contractile effect of hemoglobin. A sequence of 11 consecutive arginine groups (11R) is one of the most effective protein transduction domains (PTD). As previously reported, we could successfully fuse 11R to heme-oxigenase-1 (HO-1). The current experiments focused on the transduction efficacy and antispastic therapeutic effect of 11R-HO-1 protein in cerebral arteries. This is the first study to examine the therapeutic effect of a PTD fused vasoactive protein in cerebral arteries.
Methods: To examine the transduction efficacy of 11R-HO-1 protein in cerebral arteries, we injected the protein into the cisterna magna of male Sprague-Dawley (S-D) rats weighting 350 to 450 g. 11R-HO-1 or saline was infused into the cisterna magna of male rats. Several hours after the injection, the animals were sacrificed; the brain stems were extracted and cut at 10 micrometer on the cryostat. Immunofluorescence staining using a monoclonal mouse HO-1 antibody was performed and fluorescence intensity was measured.
A rat double-hemorrhage model of SAH was also used to assess whether protein transduction of 11R-HO-1 prevents vasospasm in vivo (total 36 rats). 0.2 ml of autologous arterial blood was injected into the cisterna magna of male rats on day 0 and day 2. Six hours before euthanasia on day 7, saline, 11R-EGFP (enhanced green fluorescent protein) or 11R-HO-1 was injected into the cisterna magna of the rats. Basilar artery (BA) diameters were measured following histological processing.
Results: With the results of immunofluorescence staining, we could prove that 11R-EGFP as well as 11R-HO-1 protein were well transduced into the rat cerebral arteries. In addition to that, the result of the rat SAH model showed that 11R-HO-1 protein had a significant effect on attenuating cerebral vasospasm after subarachnoid hemorrhage (SAH). (BA diameters: Control group [SAH only] 272.25±17.25 micrometer, 11R-EGFP injection group 292.68±18.29 micrometer, 11R-HO-1 injection group 369.43±18.66 micrometer, p<0.05).
Conclusions: 11R-HO-1 can be effectively delivered into rat BA by transcisternal application, resulting in prevention of the cerebral vasospasm after experimental SAH. This result suggest that 11R-HO-1 protein transduction into cerebral arteries may provide a novel therapeutic approach of cerebral vasospasm after SAH.