Remote post-conditioning reduces hypoxic damage early after experimental stroke

TY - JOUR

T1 - Remote post-conditioning reduces hypoxic damage early after experimental stroke

AU - Hasseldam, Henrik

AU - Hansen-Schwartz, Jacob

AU - Munkholm, Nina

AU - Hou, Jack

AU - Johansen, Flemming F

PY - 2013/5

Y1 - 2013/5

N2 - Objectives: Given that reliable markers for early ischemic brain damage are lacking, we set out to test whether pimonidazole can be used as a reliable tool in the quantification of hypoxic insults, at early time points following experimental stroke. Methods: We have used semi-quantitative Western blotting detection of pimonidazole adducts in a rat model of reversible middle cerebral artery occlusion (MCAO), treated with remote post-conditioning. Results: First, we demonstrated that a linear relationship exist between pimonidazole binding in the ischemic hemisphere and duration of ischemia, in animals subjected to 5, 15, 30, or 60 minutes of occlusion followed by 120 minutes of reflow. Then we showed a significant reduction in pimonidazole binding in the infarcted hemisphere, when rats with 60 minutes of MCAO, immediately after establishment of cerebral reflow, had 3 × 15 minutes intermittent hind limb ischemia followed by 24-hour survival. We analysed the middle cerebral arteries from animals with 60 minutes of MCAO and early remote post conditioning, followed by 30 minutes, 24, or 48 hours of reflow. At 24 hours of reflow increases in phosphorylated protein kinase C-alpha with concomitantly increased levels of p38 phosphorylation were observed. Conclusions: Our investigation demonstrates that pimonidazole can be used for quantifying ischemic impact in stroke, even after very short survival times. It furthermore shows that early remote postconditioning reduces ischemic damage, probably through hyperpolarization and reduced reflow vasospasm in the conduit middle cerebral arteries.

AB - Objectives: Given that reliable markers for early ischemic brain damage are lacking, we set out to test whether pimonidazole can be used as a reliable tool in the quantification of hypoxic insults, at early time points following experimental stroke. Methods: We have used semi-quantitative Western blotting detection of pimonidazole adducts in a rat model of reversible middle cerebral artery occlusion (MCAO), treated with remote post-conditioning. Results: First, we demonstrated that a linear relationship exist between pimonidazole binding in the ischemic hemisphere and duration of ischemia, in animals subjected to 5, 15, 30, or 60 minutes of occlusion followed by 120 minutes of reflow. Then we showed a significant reduction in pimonidazole binding in the infarcted hemisphere, when rats with 60 minutes of MCAO, immediately after establishment of cerebral reflow, had 3 × 15 minutes intermittent hind limb ischemia followed by 24-hour survival. We analysed the middle cerebral arteries from animals with 60 minutes of MCAO and early remote post conditioning, followed by 30 minutes, 24, or 48 hours of reflow. At 24 hours of reflow increases in phosphorylated protein kinase C-alpha with concomitantly increased levels of p38 phosphorylation were observed. Conclusions: Our investigation demonstrates that pimonidazole can be used for quantifying ischemic impact in stroke, even after very short survival times. It furthermore shows that early remote postconditioning reduces ischemic damage, probably through hyperpolarization and reduced reflow vasospasm in the conduit middle cerebral arteries.

U2 - 10.1179/1743132812y.0000000130

DO - 10.1179/1743132812y.0000000130

M3 - Journal article

C2 - 23540402

SN - 0161-6412

VL - 35

SP - 336

EP - 343

JO - Neurological Research

JF - Neurological Research

IS - 4

ER -