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Hyperbaric oxygen preconditioning attenuates hyperglycemia enhanced hemorrhagic transformation after transient MCAO in rats.

Soejima Y, Ostrowski RP, Manaenko A, Fujii M, Tang J, Zhang JH - Med Gas Res (2012)

Bottom Line: HBO-PC improved neurological behavior test, and reduced infarction volume, HT and Evans blue extravasation in the ipsilateral hemisphere at 24 h after MCAO.Western blot analysis failed to demonstrate up-regulation of Nrf2 in HBO-PC group before and after MCAO.Paradoxically, HBO-PC decreased HO-1 expression at 24 h after MCAO, as compared with htMCAO group.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA. johnzhang3910@yahoo.com.

ABSTRACT

Background: Hemorrhagic transformation (HT) can be a devastating complication of ischemic stroke. Hyperbaric oxygen preconditioning (HBO-PC) has been shown to improve blood-brain barrier (BBB) permeability in stroke models. The purpose of this study is to examine whether HBO-PC attenuates HT after focal cerebral ischemia, and to investigate whether the mechanism of HBO-PC against HT includes up-regulation of antioxidants in hyperglycemic rats.

Methods: Male Sprague-Dawley rats (280-320 g) were divided into the following groups: sham, middle cerebral artery occlusion (MCAO) for 2 h, and MCAO treated with HBO-PC. HBO-PC was conducted giving 100% oxygen at 2.5 atm absolute (ATA), for 1 h at every 24 h interval for 5 days. At 24 h after the last session of HBO-PC, rats received an injection of 50% glucose (6 ml/kg intraperitoneally) and were subjected to MCAO 15 min later. At 24 h after MCAO, neurological behavior tests, infarct volume, blood-brain barrier permeability, and hemoglobin content were measured to evaluate the effect of HBO-PC. Western blot analysis of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was evaluated at multiple time-points before and after MCAO.

Results: HBO-PC improved neurological behavior test, and reduced infarction volume, HT and Evans blue extravasation in the ipsilateral hemisphere at 24 h after MCAO. Western blot analysis failed to demonstrate up-regulation of Nrf2 in HBO-PC group before and after MCAO. Paradoxically, HBO-PC decreased HO-1 expression at 24 h after MCAO, as compared with htMCAO group.

Conclusions: HBO-PC improved neurological deficits, infarction volume, BBB disruption, and HT after focal cerebral ischemia. However, its mechanism against focal cerebral ischemia and HT may not include activation of Nrf2 and subsequent HO-1 expression.

No MeSH data available.


Related in: MedlinePlus

HBO preconditioning significantly reduced infarction volume and hemorrhage volume. (A) Representative whole brains and brain slices with 2,3,5-triphenyltetrazolium chloride staining of each groups were demonstrated. HBO-PC reduced infarction volume and attenuated hemorrhagic transformation. (B) Bar graphs showing average infarct size calculated in six slices. HBO-PC significantly reduced infarct volume at 24 h after reperfusion compared to htMCAO group. (C) Hemorrhage volume was significantly reduced with HBO-PC. *P > 0.05 vs. htMCAO.
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Figure 3: HBO preconditioning significantly reduced infarction volume and hemorrhage volume. (A) Representative whole brains and brain slices with 2,3,5-triphenyltetrazolium chloride staining of each groups were demonstrated. HBO-PC reduced infarction volume and attenuated hemorrhagic transformation. (B) Bar graphs showing average infarct size calculated in six slices. HBO-PC significantly reduced infarct volume at 24 h after reperfusion compared to htMCAO group. (C) Hemorrhage volume was significantly reduced with HBO-PC. *P > 0.05 vs. htMCAO.

Mentions: To examine whether HBO-PC exerts a beneficial effect on HT after focal ischemia, neurological scores, infarction volume and hemorrhagic volume were evaluated in htMCAO and HBO-PC group. HBO preconditioned animals showed statistically better neurological function as compared with those of htMCAO group (7.00 ± 1.55 versus 12.58 ± 1.36, P < 0.01; Figure 2). HBO-PC significantly reduced the infarction volume on TTC staining at 24 h after MCAO (0.260 ± 0.017 versus 0.126 ± 0.031, P < 0.01; Figure 3A, B). Spectrophotometric measurement of brain hemoglobin showed that hemoglobin contents of HBO preconditioned animals were significantly lower than those of htMCAO group (10.37 ± 1.69 versus 15.17 ± 0.76 μL/hemisphere, P < 0.05; Figure 3C).


Hyperbaric oxygen preconditioning attenuates hyperglycemia enhanced hemorrhagic transformation after transient MCAO in rats.

Soejima Y, Ostrowski RP, Manaenko A, Fujii M, Tang J, Zhang JH - Med Gas Res (2012)

HBO preconditioning significantly reduced infarction volume and hemorrhage volume. (A) Representative whole brains and brain slices with 2,3,5-triphenyltetrazolium chloride staining of each groups were demonstrated. HBO-PC reduced infarction volume and attenuated hemorrhagic transformation. (B) Bar graphs showing average infarct size calculated in six slices. HBO-PC significantly reduced infarct volume at 24 h after reperfusion compared to htMCAO group. (C) Hemorrhage volume was significantly reduced with HBO-PC. *P > 0.05 vs. htMCAO.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351373&req=5

Figure 3: HBO preconditioning significantly reduced infarction volume and hemorrhage volume. (A) Representative whole brains and brain slices with 2,3,5-triphenyltetrazolium chloride staining of each groups were demonstrated. HBO-PC reduced infarction volume and attenuated hemorrhagic transformation. (B) Bar graphs showing average infarct size calculated in six slices. HBO-PC significantly reduced infarct volume at 24 h after reperfusion compared to htMCAO group. (C) Hemorrhage volume was significantly reduced with HBO-PC. *P > 0.05 vs. htMCAO.
Mentions: To examine whether HBO-PC exerts a beneficial effect on HT after focal ischemia, neurological scores, infarction volume and hemorrhagic volume were evaluated in htMCAO and HBO-PC group. HBO preconditioned animals showed statistically better neurological function as compared with those of htMCAO group (7.00 ± 1.55 versus 12.58 ± 1.36, P < 0.01; Figure 2). HBO-PC significantly reduced the infarction volume on TTC staining at 24 h after MCAO (0.260 ± 0.017 versus 0.126 ± 0.031, P < 0.01; Figure 3A, B). Spectrophotometric measurement of brain hemoglobin showed that hemoglobin contents of HBO preconditioned animals were significantly lower than those of htMCAO group (10.37 ± 1.69 versus 15.17 ± 0.76 μL/hemisphere, P < 0.05; Figure 3C).

Bottom Line: HBO-PC improved neurological behavior test, and reduced infarction volume, HT and Evans blue extravasation in the ipsilateral hemisphere at 24 h after MCAO.Western blot analysis failed to demonstrate up-regulation of Nrf2 in HBO-PC group before and after MCAO.Paradoxically, HBO-PC decreased HO-1 expression at 24 h after MCAO, as compared with htMCAO group.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA. johnzhang3910@yahoo.com.

ABSTRACT

Background: Hemorrhagic transformation (HT) can be a devastating complication of ischemic stroke. Hyperbaric oxygen preconditioning (HBO-PC) has been shown to improve blood-brain barrier (BBB) permeability in stroke models. The purpose of this study is to examine whether HBO-PC attenuates HT after focal cerebral ischemia, and to investigate whether the mechanism of HBO-PC against HT includes up-regulation of antioxidants in hyperglycemic rats.

Methods: Male Sprague-Dawley rats (280-320 g) were divided into the following groups: sham, middle cerebral artery occlusion (MCAO) for 2 h, and MCAO treated with HBO-PC. HBO-PC was conducted giving 100% oxygen at 2.5 atm absolute (ATA), for 1 h at every 24 h interval for 5 days. At 24 h after the last session of HBO-PC, rats received an injection of 50% glucose (6 ml/kg intraperitoneally) and were subjected to MCAO 15 min later. At 24 h after MCAO, neurological behavior tests, infarct volume, blood-brain barrier permeability, and hemoglobin content were measured to evaluate the effect of HBO-PC. Western blot analysis of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was evaluated at multiple time-points before and after MCAO.

Results: HBO-PC improved neurological behavior test, and reduced infarction volume, HT and Evans blue extravasation in the ipsilateral hemisphere at 24 h after MCAO. Western blot analysis failed to demonstrate up-regulation of Nrf2 in HBO-PC group before and after MCAO. Paradoxically, HBO-PC decreased HO-1 expression at 24 h after MCAO, as compared with htMCAO group.

Conclusions: HBO-PC improved neurological deficits, infarction volume, BBB disruption, and HT after focal cerebral ischemia. However, its mechanism against focal cerebral ischemia and HT may not include activation of Nrf2 and subsequent HO-1 expression.

No MeSH data available.


Related in: MedlinePlus