scholarly journals Columnar Alterations of NADH Fluorescence during Hypoxia-Ischemia in Immature Rat Brain

1982 ◽  
Vol 2 (2) ◽  
pp. 221-228 ◽  
Author(s):  
Frank A. Welsh ◽  
Robert C. Vannucci ◽  
James B. Brierley
Keyword(s):  
Recovery Period ◽  
High Energy ◽  
High Energy Phosphates ◽  
Contralateral Hemisphere ◽  
Artery Ligation ◽  
Ipsilateral Hemisphere ◽  
Carotid Artery Ligation ◽  
Systemic Hypoxia ◽  
Nadh Fluorescence ◽  
Hypoxia Ischemia

Cerebral hypoxia-ischemia was produced in 7-day postnatal rats by unilateral carotid artery ligation combined with systemic hypoxia (8% O2). Levels of high energy phosphates, which were only slightly altered in the contralateral hemisphere, were nearly depleted in the ipsilateral hemisphere during the 3-h hypoxic insult. With hypoxia of between 1 and 3 hours' duration, columnar alterations of cortical NADH fluorescence occurred in the same location and regional pattern as did histologic damage demonstrated previously (Rice et al., 1981). In regions exhibiting columns of NADH fluorescence, there was no evidence of a columnar reduction of high energy phosphates as levels of ATP and phosphocreatine were nearly zero. Recovery from 3 h of hypoxia was accompanied by partial and regionally heterogeneous restoration of ATP within the ipsilateral hemisphere. Columnar variations of NADH fluorescence were not detected in the recovery period; rather, regions with impaired restitution of high energy phosphates exhibited NADH fluorescence that was diminished diffusely compared to the contralateral hemisphere. The correlation between depressed NADH fluorescence and depleted ATP, present as cortical columns during hypoxia and as larger regions during recovery, suggests that decreased formation of NADH may be limiting the resynthesis of high energy phosphates.

Carbon Dioxide Protects the Perinatal Brain From Hypoxic-Ischemic Damage: An Experimental Study in the Immature Rat

PEDIATRICS ◽  
1995 ◽  
Vol 95 (6) ◽  
pp. 868-874 ◽  
Author(s):  
Robert C. Vannucci ◽  
Javad Towfighi ◽  
Daniel F. Heitjan ◽  
Robert M. Brucklacher
Keyword(s):  
Carbon Dioxide ◽  
Carotid Artery ◽  
Brain Damage ◽  
Artery Ligation ◽  
Immature Rat ◽  
Rat Pups ◽  
Carotid Artery Ligation ◽  
Respiratory Management ◽  
Systemic Hypoxia ◽  
Hypoxia Ischemia

Background and Objective. Clinical investigations suggest that premature infants who require mechanical ventilation from respiratory distress syndrome are at increased risk for periventricular leukomalacia if hypocapnia occurs during respiratory management. The question remains as to the contribution of hypocapnia to hypoxic-ischemic brain damage and whether or not hypercapnia is neuroprotective. Methods. Seven-day postnatal rats underwent unilateral common carotid artery ligation followed thereafter by exposure to systemic hypoxia with 8% oxygen (O2) combined with either 0, 3, 6, or 9% carbon dioxide (CO2) for 2.5 hours at 37°C. Survivors underwent neuropathologic examination at 30 days of postnatal age, and their brains were categorized as follows: 0 = normal; 1 = mild atrophy; 2 = moderate atrophy; 3 = atrophy with cystic cavitation <3 mm; 4 = cystic cavitation >3 mm of the cerebral hemisphere ipsilateral to the carotid artery ligation. The width of the ipsilateral hemisphere also was determined on a posterior coronal section and compared with that of the contralateral hemisphere to ascertain the severity of cerebral atrophy/cavitation. Data were analyzed by linear models. Results. CO2 tensions averaged 26, 42, 54, and 71 mm Hg in the 0, 3, 6, and 9% CO2 exposed animals, respectively, during systemic hypoxia. Blood O2 tensions during hypoxia were not different among the four groups and averaged 34.7 mm Hg. Neuropathologic results showed that 30/38 (79%) rats exposed to 3% CO2 showed either no or mild brain damage compared with 13/33 (39%) controls (0% CO2). Cystic cavitation occurred in only four CO2 exposed rat pups compared with 14 controls (P = .001). At 6% CO2 exposure, all of 20 rat pups showed either no damage or mild atrophy compared with controls (P < .001); and at 9% CO2 exposure, 19/23 (83%) rat pups showed no or mild damage compared with controls (P < .001). The data also showed that the greatest reduction in brain damage occurred in immature rats exposed to 6% CO2 with slightly less protection at 9% CO2 (P = .012), the latter comparable with the severity of brain damage sustained by animals inhaling 3% CO2. Analyses of coronal width ratios at each CO2 exposure provided results comparable with those of the gross neuropathology scores. Conclusions. The results indicate that in an immature rat model normocapnic cerebral hypoxia-ischemia is associated with less severe brain damage than in hypocapnic hypoxia-ischemia and that mild hypercapnia is more protective than normocapnia. The findings in an experimental model merit further animal investigations as well as a clinical reappraisal of the ventilatory management of sick newborn human infants.

Cerebral energy metabolism during hypoxia-ischemia and early recovery in immature rats

1992 ◽  
Vol 262 (3) ◽  
pp. H672-H677 ◽  
Author(s):  
J. Y. Yager ◽  
R. M. Brucklacher ◽  
R. C. Vannucci
Keyword(s):  
Carotid Artery ◽  
Brain Damage ◽  
Adenine Nucleotides ◽  
High Energy ◽  
Cerebral Hypoxia ◽  
High Energy Phosphate ◽  
Early Recovery ◽  
Artery Ligation ◽  
Carotid Artery Ligation ◽  
Hypoxia Ischemia

Persistent alterations in cellular energy homeostasis may contribute to the brain damage that evolves from perinatal cerebral hypoxia-ischemia. Accordingly, the presence and extent of perturbations in high-energy phosphate reserves were analyzed during hypoxia-ischemia and the early recovery period in the immature rat. Seven-day postnatal rats were subjected to unilateral common carotid artery ligation and hypoxia with 8% oxygen at 37 degrees C for 3 h, an insult that produces damage (selective neuronal necrosis or infarction) of the cerebral hemisphere ipsilateral to the common carotid artery ligation in 92% of animals. Rat pups were quick frozen in liquid nitrogen during hypoxia-ischemia and at 10, 30, and 60 min and 4 and 24 h of recovery for enzymatic, fluorometric analysis of phosphocreatine (PCr), creatine, ATP, ADP, and AMP. During hypoxia-ischemia, PCr, ATP, and total adenine nucleotides were decreased by 87, 72, and 50% of control, respectively. During recovery, PCr, ATP, and total adenine nucleotides exhibited a rapid (within 10 min) although incomplete and heterogeneous recovery that persisted for at least 24 h. Mean values for PCr remained between 55 and 85% of control, whereas ATP values remained between 57 and 67% of control. Individual ATP values were inversely related to tissue water content at 10 min of recovery, indicating a close correlation between failure of energy restoration and the extent of cerebral edema as a reflection of brain damage. Thus high-energy phosphate reserves display lingering alterations during recovery from hypoxia-ischemia. The interanimal variability in energy restoration presumably reflects the spectrum of brain damage seen in this model of perinatal cerebral hypoxia-ischemia.

scholarly journals Temporal Changes of Regional Glucose Use, Blood Flow, and Microtubule-Associated Protein 2 Immunostaining after Hypoxia—Ischemia in the Immature Rat Brain

1998 ◽  
Vol 18 (2) ◽  
pp. 222-228 ◽  
Author(s):  
Eric Gilland ◽  
Elsa Bona ◽  
Henrik Hagber
Keyword(s):  
Secondary Phase ◽  
Contralateral Side ◽  
Energy Utilization ◽  
Artery Ligation ◽  
Early Reperfusion ◽  
Immature Rat ◽  
Ipsilateral Hemisphere ◽  
Carotid Artery Ligation ◽  
Hypoxia Ischemia ◽  
Old Rats

In a situation with normal CBF and without increased energy utilization, increased glucose utilization (CMRglc) can be a sign of impaired mitochondrial metabolism, which may be an early step in the injury cascade during reperfusion after hypoxia–ischemia (HI). Seven-day-old rats underwent unilateral carotid artery ligation and 70 minutes of HI. At 3, 6, 12, 24, and 48 or 72 hours after the insult, the CMRglc was measured by the 2-deoxyglucose method, and CBF by the iodoantipyrine method. These were compared with hematoxylin-eosin staining and microtubule-associated protein 2 (MAP 2) immunostaining in adjacent sections. In the ipsilateral hemisphere, there appeared regions with increased CMRglc compared with the contralateral hemisphere 3 to 12 hours after HI that also showed partial loss of MAP 2 immunostaining and early ischemic changes. These areas receded, leaving central glucose hypoutilizing areas with complete loss of MAP 2 immunostaining and histologic infarction, surrounded by only a rim of tissue with increased CMRglc. At 24 and 72 hours after the insult, no regions with increased CMRglc remained. Despite loss of MAP 2 immunostaining and histologic signs of infarction at 24 hours, cortical CBF was not reduced until 48 hours after HI, whereas the CBF in the caudate-putamen already was decreased compared with the contralateral side at 3 hours after HI. In conclusion, early reperfusion is characterized by glucose hyperutilizing areas in the cerebral cortex, followed by a secondary phase with low CMRglc and infarction.

Cerebral oxidative metabolism and redox state during hypoxia-ischemia and early recovery in immature rats

1991 ◽  
Vol 261 (4) ◽  
pp. H1102-H1108
Author(s):  
J. Y. Yager ◽  
R. M. Brucklacher ◽  
R. C. Vannucci
Keyword(s):  
Carotid Artery ◽  
Tricarboxylic Acid Cycle ◽  
Recovery Period ◽  
High Energy ◽  
Artery Occlusion ◽  
High Energy Phosphate ◽  
Early Recovery ◽  
Artery Ligation ◽  
Hypoxia Ischemia ◽  
Mitochondrial Oxidation

Intracellular pH (pHi) and cytoplasmic and mitochondrial oxidation-reduction (redox) states of cerebral tissue were examined in relation to perturbations of glycolytic and tricarboxylic acid cycle intermediates and of high-energy phosphate reserves during hypoxia-ischemia and the early recovery period in the immature rat. Seven-day postnatal rats underwent unilateral common carotid artery ligation and exposure to 8% O2 for 3 h, after which they were quick frozen in liquid N2 at the terminus of hypoxia-ischemia and at 10, 30, 60, and 240 min of recovery for enzymatic fluorometric analysis of cerebral metabolites. During hypoxia-ischemia, concentrations of glucose and alpha-ketoglutarate in the cerebral hemisphere ipsilateral to the carotid artery occlusion were depleted to 10 and 70% of control, respectively; pyruvate was unchanged. During recovery, glucose, pyruvate, and alpha-ketoglutarate increased above their respective control values. Calculated pHi decreased from 7.0 (control) to 6.6 during hypoxia-ischemia and normalized by 10 min of recovery. The cytoplasmic NAD+/NADH ratio decreased (increased reduction) to 50% of control during hypoxia-ischemia and remained in the reduced state throughout 4 h of recovery. Paradoxically, mitochondrial NAD+/NADH was oxidized at the terminus of hypoxia-ischemia. The mitochondrial oxidation which developed during hypoxia-ischemia presumably results from a limitation of cellular substrate (glucose) supply, which in turn leads to a depletion of high-energy phosphate reserves, culminating in brain damage.

scholarly journals Experimental Stroke in the Female Diabetic, db/db, Mouse

2001 ◽  
Vol 21 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Susan J. Vannucci ◽  
Lisa B. Willing ◽  
Shozo Goto ◽  
Nabil J. Alkayed ◽  
Robert M. Brucklacher ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Brain Damage ◽  
Common Carotid Artery ◽  
Genetic Model ◽  
Infarct Volume ◽  
High Energy ◽  
Experimental Stroke ◽  
Artery Ligation ◽  
Carotid Artery Ligation ◽  
Underlying Mechanisms

Diabetic hyperglycemia increases brain damage after cerebral ischemia in animals and humans, although the underlying mechanisms remain unclear. Gender-linked differences in ischemic tolerance have been described but have not been studied in the context of diabetes. In the current study, we used a model of unilateral common carotid artery ligation, combined with systemic hypoxia, to study the effects of diabetes and gender on hypoxic–ischemic (HI) brain damage in the genetic model of Type II diabetes, the db/db, mouse. Male and female, control and db/db, mice were subjected to right common carotid artery ligation followed by varying periods of hypoxia (8% oxygen/92% nitrogen) to assess mortality, infarct volume, and tissue damage by light microscopic techniques. End-ischemic regional cerebral blood flow (CBF) was determined using [14C] iodoantipyrine autoradiography. Glycolytic and high energy phosphate compounds were measured in blood and brain by enzymatic and fluorometric techniques. Gender and diabetes had significant effects on mortality from HI and extent of brain damage in the survivors. Female mice were more resistant than their male counterparts, such that the severity (mortality and infarction size) in the male diabetics > female diabetics ~ male controls > female controls. End-ischemic CBF and depletion of cerebral high energy reserves were comparable among all groups. Surprisingly, female diabetic mice were more hyperglycemic and demonstrated a greater prolonged lactacidosis than the males; however, they were more resistant to damage. The results suggest a unique pathophysiology of hypoxia–ischemia in the female diabetic brain.

Transient changes in muscle high-energy phosphates during moderate exercise

1993 ◽  
Vol 75 (2) ◽  
pp. 648-656 ◽  
Author(s):  
G. D. Marsh ◽  
D. H. Paterson ◽  
J. J. Potwarka ◽  
R. T. Thompson
Keyword(s):  
Oxygen Consumption ◽  
Steady State ◽  
Recovery Period ◽  
High Energy ◽  
Second Order ◽  
Moderate Intensity ◽  
High Energy Phosphates ◽  
Order Model ◽  
Time Constants ◽  
First Order

The purpose of this study was to use 31P-nuclear magnetic resonance spectroscopy to examine changes in wrist flexor muscle metabolism during the transitions from rest to steady-state exercise (on-transient) and back to rest (off-transient). Five healthy young males (mean age 25 +/- 2 yr) performed a series of square-wave exercise tests, each consisting of 5 min of moderate-intensity work followed by a 5-min recovery period. The subjects repeated this protocol six times, and each individual's results were pooled before analysis. ATP and intracellular pH did not change significantly during exercise or recovery. Phosphocreatine (PCr) declined progressively at the onset of exercise, reaching a plateau after approximately 2 min. A reciprocal increase in Pi occurred during the onset of exercise. During the recovery period PCr was resynthesized, whereas Pi returned to resting levels. The data were plotted as a function of time and fit with both first- and second-order exponential growth or decay models; however, the second-order model did not significantly improve the fit of the data. Time constants for the first-order model of the on- and off-transient responses for both PCr and Pi were approximately 30 s. These values are nearly identical to the time constants for oxygen consumption during submaximal exercise that have been reported previously by several authors. The results of this study show that the metabolism of muscle PCr during steady-state exercise and recovery can be accurately described by a monoexponential model and, further, suggest that a first-order proportionality exists between metabolic substrate utilization and oxygen consumption.

scholarly journals Regional Alterations of ATP and Heat-Shock Protein-72 mRNA following Hypoxia—Ischemia in Neonatal Rat Brain

1995 ◽  
Vol 15 (6) ◽  
pp. 1047-1056 ◽  
Author(s):  
Shuichi Kobayashi ◽  
Frank A. Welsh
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Cell Injury ◽  
Surface Expression ◽  
Subcortical White Matter ◽  
Neonatal Rat ◽  
Heat Shock Protein 72 ◽  
Artery Ligation ◽  
Ipsilateral Hemisphere ◽  
Hypoxia Ischemia

Neonatal rats, 7 days of age, underwent unilateral carotid artery ligation followed by exposure to hypoxia (8% O2) for 80 min. At the end of the period of hypoxia, and after recovery for 2 or 24 h, regional levels of ATP and heat-shock protein-72 (hsp72) mRNA were measured in adjacent brain sections using ATP-luminescence histochemistry and in situ hybridization, respectively. At the end of hypoxia, ATP levels were decreased in a patchy pattern within the hemisphere ipsilateral to the carotid ligation. In the parietal cortex, the reduction of ATP often occurred in columns oriented perpendicular to the cortical surface. Expression of hsp72 mRNA was not detected prior to recovery, except in the ventricular lining of the ipsilateral hemisphere. However, by 2 h of recovery, hsp72 mRNA was expressed in a diffuse pattern in the ipsilateral hemisphere, even in regions in which the distribution of ATP remained patchy. Although the regional extent of expression varied in different animals, hsp72 mRNA was expressed consistently in the subcortical white matter, which, in some animals, was the only region showing expression. In contrast to the diffuse pattern of expression at 2 h of recovery, expression of hsp72 mRNA at 24 h was highly localized in the superficial layers of cerebral cortex and the pyramidal cell layer of hippocampus. The present results demonstrate that hypoxia–ischemia causes regionally distinct alterations in ATP and hsp72 mRNA that may be related to cell injury in this model.

scholarly journals Global Gene Expression in the Immature Brain after Hypoxia-Ischemia

2004 ◽  
Vol 24 (12) ◽  
pp. 1317-1332 ◽  
Author(s):  
Hedtjärn Maj ◽  
Carina Mallard ◽  
Saskia Eklind ◽  
Katarina Gustafson-Brywe ◽  
Henrik Hagberg
Keyword(s):  
Global Gene Expression ◽  
Differentially Expressed ◽  
Global Changes ◽  
Artery Ligation ◽  
Oligonucleotide Arrays ◽  
Genomic Changes ◽  
Neonatal Hypoxia ◽  
Carotid Artery Ligation ◽  
New Genes ◽  
Hypoxia Ischemia

Ischemia induces a complex response of differentially expressed genes in the brain. In order to understand the specific mechanisms of injury in the developing brain, it is important to obtain information on global changes in the transcriptome after neonatal hypoxia-ischemia. In this study, oligonucleotide arrays were used to investigate genomic changes at 2, 8, 24, and 72 hours after neonatal hypoxia-ischemia, which was induced in 9-day-old mice by left carotid artery ligation followed by hypoxia (10% O2). In total, 343 genes were differentially expressed in cortex, hippocampus, thalamus, and striatum 2 to 72 hours after hypoxia-ischemia, when comparing ipsilateral with contralateral hemispheres and with controls, using the significance analysis for microarrays. A total of 283 genes were upregulated and 60 were downregulated, and 94% of the genes had not previously been shown after neonatal hypoxia-ischemia. Genes related to transcription factors and metabolism had mostly upregulated transcripts, whereas most downregulated genes belonged to the categories of ion and vesicular transport and signal transduction. Genes involved in transcription, stress, and apoptosis were induced early after the insult, and many new genes that may play important roles in the pathophysiology of neonatal hypoxiaischemia were identified.

Hypoxia-induced functional alterations in adult rat neocortex

1992 ◽  
Vol 67 (4) ◽  
pp. 798-811 ◽  
Author(s):  
H. J. Luhmann ◽  
U. Heinemann
Keyword(s):  
Synaptic Transmission ◽  
Recovery Period ◽  
Field Potential ◽  
Reversal Potential ◽  
Input Resistance ◽  
High Energy ◽  
High Energy Phosphates ◽  
Inhibitory System ◽  
Paired Pulse ◽  
Inhibitory Synaptic Transmission

1. Brief periods of hypoxia (2-7 min) were induced in rat neocortical slices maintained in an interface-type recording chamber at 34-35 degrees C by changing the aerating gas from 95% O2-5% CO2 to 95% N2-5% CO2. Field potential (FP) and intracellular recordings were obtained in layers II/III of primary somatosensory cortex. Intracellular injection of biocytin revealed the characteristic morphology of supragranular spiny pyramidal neurons. 2. Excitatory synaptic transmission reversibly decreased by 45% as estimated from FP responses to orthodromic stimulation of the underlying white matter/layer VI. Excitatory postsynaptic potentials (EPSPs) were suppressed by 36% in amplitude and recovered within 2-3 min after reoxygenation. During the recovery period, EPSPs showed a reversible increase in duration by 72%. 3. Inhibitory synaptic transmission was completely blocked as determined in FP responses with a paired-pulse inhibition protocol. The fast inhibitory postsynaptic potential (IPSP) declined by 58% during hypoxia. The long-lasting IPSP was suppressed by 75% and showed incomplete recovery. During hypoxia, the amplitude of both IPSPs was significantly more strongly suppressed than the EPSP. 4. In 40% of the cells, hypoxia induced an early anoxic hyperpolarization with a reversal potential of E = -80.8 mV, followed by a postanoxic hyperpolarization (E = -89.4 mV). In a second group of cells (37%), a gradual anoxic depolarization with E = -57.5 mV was observed instead of an early hyperpolarization. In both groups of cells, the anoxic response was associated with a marked decrease in input resistance, by 42 and 31%, respectively. 5. The spike discharge frequency was reversibly suppressed by 71% during hypoxia. A transient hyperexcitability accompanied with a rise in input resistance and discharge rate was observed in 38% of the cells on reoxygenation. 6. The reversal potential of the anoxic hyperpolarization was unaffected by tetrodotoxin (TTX) but was significantly altered by application of the ATP-sensitive K+ channel (KATP) blocker gliquidone. Application of gliquidone additionally resulted in a significantly smaller hypoxia-induced decline in paired-pulse inhibition. 7. Increases in tissue high-energy phosphates induced by preincubating the slices in 25 mM creatine for greater than 2 h had a pronounced protective effect on excitatory and inhibitory synaptic transmission. 8. These data suggest a selective vulnerability of the neocortical inhibitory system during hypoxia. Our results further indicate that hypoxia activates a pre- and postsynaptic KATP conductance because of the decline in intracellular ATP.

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