The development of an improved preclinical mouse model of intracerebral hemorrhage using double infusion of autologous whole blood.

The present study was conducted in mice to validate a double blood infusion model of intracerebral hemorrhage (ICH) that does not use anticoagulant. We investigated the effect of intrastriatal infusion of blood on hematoma volume, neurologic function, brain edema and swelling, and markers of neuroinflammation and oxidative DNA damage. Anesthetized C57BL/6 adult male mice were infused in the left striatum with 4 microl of blood over 20 min at 0.2 microl /min; the needle was left in place for 7 min, and the remaining 6 microl of blood was then infused over 30 min. The injection needle was slowly withdrawn 20 min after the second injection. Sham-operated control mice received only needle insertion. The hematoma produced in this model was primarily restricted to the striatum, and the mice demonstrated severe neurologic deficits that appeared within 60 min and remained evident at 72 h. Brain water content and swelling were significantly increased and were associated with a marked increase in ICH-induced neutrophil infiltration, microglial/macrophage and astrocyte activation, cytochrome c release, and oxidative DNA damage. Other groups have mixed the anticoagulant heparin with the infused blood, an agent that could affect in vivo clot formation. We believe that this double blood infusion model that does not use anticoagulant improves upon the procedure and provides an easy and reproducible alternative for inducing ICH in mice; it should be useful for studying the pathophysiology of ICH and for testing potential pharmaceutical and surgical interventions.

Role of Nrf2 in protection against intracerebral hemorrhage injury in mice.

Nrf2 is a key transcriptional factor for antioxidant response element (ARE)-regulated genes. While its beneficial role has been described for stroke, its contribution to intracerebral hemorrhage (ICH)-induced early brain injury remains to be determined. Using wild-type (WT) and Nrf2 knockout (Nrf2(-/-)) mice, the role of Nrf2 in ICH induced by intracerebral injection of collagenase was investigated. The results showed that injury volume was significantly larger in Nrf2(-/-) mice than in WT controls 24 h after induction of ICH (P<0.05), an outcome that correlated with neurological deficits. This exacerbation of brain injury in Nrf2(-/-) mice was also associated with an increase in leukocyte infiltration, production of reactive oxygen species, DNA damage, and cytochrome c release during the critical early phase of the post-ICH period. In combination, these results suggest that Nrf2 reduces ICH-induced early brain injury, possibly by providing protection against leukocyte-mediated free radical oxidative damage.