Browsing by Subject "Laser-Doppler Flowmetry"

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    ItemOpen Access
    A blinded randomized assessment of laser Doppler flowmetry efficacy in standardizing outcome from intraluminal filament MCAO in the rat.
    (Journal of neuroscience methods, 2015-02) Taninishi, Hideki; Jung, Jin Yong; Izutsu, Miwa; Wang, Zhengfeng; Sheng, Huaxin; Warner, David S

    Background

    Laser Doppler flowmetry (LDF) is widely used for estimating cerebral blood flow changes during intraluminal middle cerebral artery occlusion (MCAO). No investigation has systematically examined LDF efficacy in standardizing outcome. We examined MCAO histologic and behavioral outcome as a function of LDF measurement.

    Materials and methods

    Rats were subjected to 90min MCAO by 4 surgeons having different levels of MCAO surgical experience. LDF was measured in all rats during ischemia. By random assignment, LDF values were (Assisted) or were not (Blinded) made available to each surgeon during MCAO (n=12-17 per group). Neurologic and histologic outcomes were measured 7 days post-MCAO. A second study examined LDF effects on 1-day post-MCAO outcome.

    Results

    Pooled across surgeons, intra-ischemic %LDF change (P=0.12), neurologic scores (Assisted vs. Blinded=14±6 vs. 13±7, P=0.61, mean±standard deviation) and cerebral infarct volume (162±63mm(3)vs. 143±86mm(3), P=0.24) were not different between groups. Only for one surgeon (novice) did LDF use alter infarct volume (145±28mm(3)vs. 98±61mm(3), P=0.03). LDF use decreased infarct volume coefficient of variation (COV) by 35% (P=0.02), but had no effect on neurologic score COV.

    Comparison with existing methods

    We compared intraluminal MCAO outcome as a function of LDF use.

    Conclusions

    LDF measurement altered neither neurologic nor histologic MCAO outcome. LDF did not decrease neurologic deficit COV, but did decrease infarct volume COV. LDF may allow use of fewer animals if infarct volume is the primary dependent variable, but is unlikely to impact requisite sample sizes if neurologic function is of primary interest.
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    ItemOpen Access
    Neuroprotective efficacy from a lipophilic redox-modulating Mn(III) N-Hexylpyridylporphyrin, MnTnHex-2-PyP: rodent models of ischemic stroke and subarachnoid hemorrhage.
    (The Journal of pharmacology and experimental therapeutics, 2011-09) Sheng, Huaxin; Spasojevic, Ivan; Tse, Hubert M; Jung, Jin Yong; Hong, Jun; Zhang, Zhiquan; Piganelli, Jon D; Batinic-Haberle, Ines; Warner, David S
    Intracerebroventricular treatment with redox-regulating Mn(III) N-hexylpyridylporphyrin (MnPorphyrin) is remarkably efficacious in experimental central nervous system (CNS) injury. Clinical development has been arrested because of poor blood-brain barrier penetration. Mn(III) meso-tetrakis (N-hexylpyridinium-2-yl) porphyrin (MnTnHex-2-PyP) was synthesized to include four six-carbon (hexyl) side chains on the core MnPorphyrin structure. This has been shown to increase in vitro lipophilicity 13,500-fold relative to the hydrophilic ethyl analog Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP). In normal mice, we found brain MnTnHex-2-PyP accumulation to be ∼9-fold greater than MnTE-2-PyP 24 h after a single intraperitoneal dose. We then evaluated MnTnHex-2-PyP efficacy in outcome-oriented models of focal cerebral ischemia and subarachnoid hemorrhage. For focal ischemia, rats underwent 90-min middle cerebral artery occlusion. Parenteral MnTnHex-2-PyP treatment began 5 min or 6 h after reperfusion onset and continued for 7 days. Neurologic function was improved with both early (P = 0.002) and delayed (P = 0.002) treatment onset. Total infarct size was decreased with both early (P = 0.03) and delayed (P = 0.01) treatment. MnTnHex-2-PyP attenuated nuclear factor κB nuclear DNA binding activity and suppressed tumor necrosis factor-α and interleukin-6 expression. For subarachnoid hemorrhage, mice underwent perforation of the anterior cerebral artery and were treated with intraperitoneal MnTnHex-2-PyP or vehicle for 3 days. Neurologic function was improved (P = 0.02), and vasoconstriction of the anterior cerebral (P = 0.0005), middle cerebral (P = 0.003), and internal carotid (P = 0.015) arteries was decreased by MnTnHex-2-PyP. Side-chain elongation preserved MnPorphyrin redox activity, but improved CNS bioavailability sufficient to cause improved outcome from acute CNS injury, despite delay in parenteral treatment onset of up to 6 h. This advance now allows consideration of MnPorphyrins for treatment of cerebrovascular disease.