Supravital Staining of Mammalian Brain with Intraarterial Methylene Blue Followed by Pressurized Oxygen

OʼLeary, James L.; Petty, Jerry; Harris, A. Basil; Inukai, Joseph

doi:10.3109/10520296809115068

Cited by 29 publications

(13 citation statements)

References 4 publications

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“…MB concentration in the brain is 10-20 times higher than that in the circulation after intravenous injection in rats. 29 No negative side effects of MB in animals or humans at low doses of MB (0.5-5 mg/kg) have been reported, 4,11 but adverse effects (e.g., methemoglobinemia) have been reported at high MB doses (> 10mg/kg) 11 because MB interferes with electron transfer function in the mitochondria. The dosage utilized in this study was based on published results that daily low-dose MB is safe in humans and rats.…”

Section: Discussionmentioning

confidence: 99%

Methylene Blue Is Neuroprotective against Mild Traumatic Brain Injury

Watts

Long

Chemello

et al. 2014

Journal of Neurotrauma

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Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Methylene blue (MB) has known energy-enhancing and antioxidant properties. This study tested the hypothesis that MB treatment reduces lesion volume and behavioral deficits in a rat model of mild TBI. In a randomized double-blinded design, animals received either MB (n = 5) or vehicle (n = 6) after TBI. Studies were performed on 0, 1, 2, 7, and 14 days following an impact to the primary forelimb somatosensory cortex. MRI lesion was not apparent 1 h after TBI, became apparent 3 h after TBI, and peaked at 2 days for both groups. The MB-treated animals showed significantly smaller MRI lesion volume than the vehicle-treated animals at all time points studied. The MB-treated animals exhibited significantly improved scores on forelimb placement asymmetry and foot fault tests than did the vehicle-treated animals at all time points studied. Smaller numbers of darkstained Nissl cells and Fluoro-Jade Ò positive cells were observed in the MB-treated group than in vehicle-treated animals 14 days post-TBI. In conclusion, MB treatment minimized lesion volume, behavioral deficits, and neuronal degeneration following mild TBI. MB is already approved by the United States Food and Drug Administration (FDA) to treat a number of indications, likely expediting future clinical trials in TBI.

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Section: Discussionmentioning

confidence: 99%

Methylene Blue Is Neuroprotective against Mild Traumatic Brain Injury

Watts

Long

Chemello

et al. 2014

Journal of Neurotrauma

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“…Recently MB has been proposed as a potential treatment for cancer 25 , hepatopulmonary syndrome 26 , and septic shock 27,28 . Furthermore, the neuroprotective function of MB, which is able to traverse the BBB, has been reported 29 . Our previous studies have demonstrated that MB increases ATP synthesis and minimizes ROS generation 30,31 .…”

Section: Introductionmentioning

confidence: 99%

Methylene blue-induced neuronal protective mechanism against hypoxia-reoxygenation stress

Ryou¹,

Choudhury²,

Li³

et al. 2015

Neuroscience

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Brain ischemia and reperfusion (I/R) injury occurs in various pathological conditions, but there is no effective treatment currently available in clinical practice. Methylene blue (MB) is a century old drug with a newly discovered protective function in the ischemic stroke model. In the current investigation we studied the MB-induced neuroprotective mechanism focusing on stabilization and activation of hypoxia inducible factor-1α (HIF-1α) in an in vitro oxygen and glucose deprivation (OGD)-reoxygenation model. Methods HT22 cells were exposed to OGD (0.1% O2, 6h) and reoxygenation (21% O2, 24h). Cell viability was determined with the calcein AM assay. The dynamic change of intracellular O2 concentration was monitored by fluorescence lifetime imaging microscopy (FLTIM). Glucose uptake was quantified using the 2-[N-(7-Nitrobenz-2-Oxa- 1,3-Diazol-4-yl)Amino]- 2-Deoxy-D-Glucose (2-NBDG) assay. ATP concentration and glycolytic enzyme activity were examined by spectrophotometry. Protein content changes were measured by immunoblot: HIF-1α, prolyl hydroxylase 2(PHD2), erythropoietin (EPO), Akt, mTOR, and PIP5K. The contribution of HIF-1α activation in the MB-induced neuroprotective mechanism was confirmed by blocking HIF-1α activation with 2-methoxyestradiol-2 (2-MeOE2) and by transiently transfecting constitutively active HIF-1α. Results MB increases cell viability by about 50% vs. OGD control. Compared to the corresponding control, MB increases intracellular O2 concentration and glucose uptake as well as the activities of hexokinase and G-6-PDH, and ATP concentration. MB activates the EPO signaling pathway with a corresponding increase in HIF-1α. Phosphorylation of Akt was significantly increased with MB treatment followed by activation of the mTOR pathway. Importantly, we observed, MB increased nuclear translocation of HIF-1α vs. control (about 3 folds), which was shown by a ratio of nuclear:cytoplasmic HIF-1α protein content. Conclusion We conclude that MB protects the hippocampus derived neuronal cells against OGD-reoxygenation injury by enhancing energy metabolism and increasing HIF-1α protein content accompanied by an activation of the EPO signaling pathway.

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“…Indeed, MB administration has been used as a selective supravital stain of nerve cells for over one hundred years. In particular, when injected intraperitoneally into live rats, MB crosses the blood-brain barrier and selectively stains brain tissue, which can be made visible after dissection when reoxidized because MB regains its blue color (O'Leary et al, 1968). Detailed pharmacokinetic studies of MB's organ distribution have shown that MB is selectively trapped in the brain and that its concentration is 10-20 times higher in the brain than in the circulation one hour following systemic administration (Peter et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

The brain metabolic enhancer methylene blue improves discrimination learning in rats

Wrubel

Riha

Maldonado

et al. 2007

Pharmacology Biochemistry and Behavior

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Methylene blue (MB) is a metabolic enhancer that has been demonstrated to improve memory retention when given post-training in low doses in a variety of tasks in rats, including inhibitory avoidance, spatial memory (in both normal and metabolically-impaired subjects), object recognition, and habituation to a familiar environment. MB has been also shown to improve memory retention of extinction of fear conditioning in the rat. No experiments have been conducted to determine the effects of MB on more complex learning such as in discrimination tasks that require repeated days of training. This study examined the effects of daily MB on spatial discrimination memory in a baited holeboard maze. Following three days of discrimination training, subjects treated daily with posttraining MB (1 mg/kg) reliably discriminated between rewarded (baited) and non-rewarded (unbaited) trials as indicated by a greater number of correct responses on rewarded trials than nonrewarded trials during the last three days of discrimination training. No such discrimination effects were observed in the saline-treated control group during the same training period. To determine whether the memory-enhancing effects of MB are associated with an increase in metabolic energy capacity in the brain, cytochrome c oxidation was measured in brains from rats treated with 1 mg/ kg MB or saline for three days. The number of daily injections was chosen based on the behavioral data which revealed group differences three days after the beginning of MB treatment. Brain cytochrome oxidase activity in the MB-treated group was approximately 70% higher than in salinetreated rats. The findings suggest that repeated post-training MB may improve memory consolidation between days of learning by an induction in the enzyme cytochrome oxidase, leading to increased metabolic capacity in brain regions requiring more energy during discrimination learning.

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Supravital Staining of Mammalian Brain with Intraarterial Methylene Blue Followed by Pressurized Oxygen

Cited by 29 publications

References 4 publications

Methylene Blue Is Neuroprotective against Mild Traumatic Brain Injury

Methylene Blue Is Neuroprotective against Mild Traumatic Brain Injury

Methylene blue-induced neuronal protective mechanism against hypoxia-reoxygenation stress

The brain metabolic enhancer methylene blue improves discrimination learning in rats

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