1H nuclear magnetic resonance brain metabolomics in neonatal mice after hypoxia-ischemia distinguished normothermic recovery from mild hypothermia recoveries.
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ABSTRACT:
SUBMITTER: Liu J
PROVIDER: S-EPMC3734529 | biostudies-other | 2013 Aug
REPOSITORIES: biostudies-other
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Project description:Therapeutic hypothermia is the standard of clinical care for moderate neonatal hypoxic-ischemic encephalopathy. We investigated the independent and interactive effects of hypoxia-ischemia (HI) and temperature on neuronal survival and injury in basal ganglia and cerebral cortex in neonatal piglets. Male piglets were randomized to receive HI injury or sham procedure followed by 29 h of normothermia, sustained hypothermia induced at 2 h, or hypothermia with rewarming during fentanyl-nitrous oxide anesthesia. Viable and injured neurons and apoptotic profiles were counted in the anterior putamen, posterior putamen, and motor cortex at 29 h after HI injury or sham procedure. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) identified genomic DNA fragmentation to confirm cell death. Though hypothermia after HI preserved viable neurons in the anterior and posterior putamen, hypothermia prevented neuronal injury in only the anterior putamen. Hypothermia initiated 2 h after injury did not protect against apoptotic cell death in either the putamen or motor cortex, and rewarming from hypothermia was associated with increased apoptosis in the motor cortex. In non-HI shams, sustained hypothermia during anesthesia was associated with neuronal injury and corresponding viable neuron loss in the anterior putamen and motor cortex. TUNEL confirmed increased neurodegeneration in the putamen of hypothermic shams. Anesthetized, normothermic shams did not show abnormal neuronal cytopathology in the putamen or motor cortex, thereby demonstrating minimal contribution of the anesthetic regimen to neuronal injury during normothermia. We conclude that the efficacy of hypothermic protection after HI is region specific and that hypothermia during anesthesia in the absence of HI may be associated with neuronal injury in the developing brain. Studies examining the potential interactions between hypothermia and anesthesia, as well as with longer durations of hypothermia, are needed.
| S-EPMC6732227 | biostudies-literature
Project description:BackgroundTherapeutic hypothermia (TH) is the standard of care for neonates with hypoxic-ischemic encephalopathy, but it is not fully protective in the clinical setting. Hypoxia-ischemia (HI) may cause white matter injury (WMI), leading to neurological and cognitive dysfunction.MethodsP9 mice were subjected to HI as previously described. Pups underwent 3.5?h of systemic hypothermia or normothermia. Cresyl violet and Perl's iron staining for histopathological scoring of brain sections was completed blindly on all brains. Immunocytochemical (ICC) staining for myelin basic protein (MBP), microglia (Iba1), and astrocytes (glia fibrillary acidic protein (GFAP)) was performed on adjacent sections. Volumetric measurements of MBP coverage were used for quantitative analysis of white matter.ResultsTH provided neuroprotection by injury scoring for the entire group (n=44; P<0.0002). ICC analysis of a subset of brains showed that the lateral caudate was protected from WMI (P<0.05). Analysis revealed decreased GFAP and Iba1 staining in hippocampal regions, mostly CA2/CA3. GFAP and Iba1 directly correlated with injury scores of normothermic brains.ConclusionTH reduced injury, and qualitative data suggest that hippocampus and lateral caudate are protected from HI. Mildly injured brains may better show the benefits of TH. Overall, these data indicate regional differences in WMI susceptibility and inflammation in a P9 murine HI model.
| S-EPMC5570671 | biostudies-literature
Project description:Therapeutic hypothermia (TH) is standard treatment following perinatal asphyxia in newborn infants. Experimentally, TH is neuroprotective after moderate hypoxia-ischemia (HI) in seven-day-old (P7) rats. However, TH is not neuroprotective after severe HI. After a moderate HI insult in newborn brain injury models, the anesthetic gas xenon (Xe) doubles TH neuroprotection. The aim of this study was to examine whether combining Xe and TH is neuroprotective as applied in a P7 rat model of severe HI.120 P7 rat pups underwent a severe HI insult; unilateral carotid artery ligation followed by hypoxia (8% O2 for 150min at experimental normothermia (NT-37: Trectal 37°C). Surviving pups were randomised to immediate NT-37 for 5h (n = 36), immediate TH-32: Trectal 32°C for 5h (n = 25) or immediate TH-32 plus 50% inhaled Xe for 5h (n = 24). Pups were sacrificed after one week of survival. Relative area loss of the ligated hemisphere was measured, and neurons in the subventricular zone of this injured hemisphere were counted, to quantify brain damage.Following the HI insult, median (interquartile range, IQR) hemispheric brain area loss was similar in all groups: 63.5% (55.5-75.0) for NT-37 group, 65.0% (57.0-65.0) for TH-32 group, and 66.5% (59.0-72.0) for TH-32+Xe50% group (not significant). Correspondingly, there was no difference in neuronal cell count (NeuN marker) in the subventricular zone across the three treatment groups.Immediate therapeutic hypothermia with or without additional 50% inhaled Xe, does not provide neuroprotection one week after severe HI brain injury in the P7 neonatal rat. This model aims to mimic the clinical situation in severely asphyxiated neonates and treatment these newborns remains an ongoing challenge.
| S-EPMC4890818 | biostudies-literature
Project description:The NaKCl cotransporter NKCC1 facilitates intraneuronal chloride accumulation in the developing brain. Bumetanide (BUM), a clinically available diuretic, inhibits this chloride transporter and augments the antiepileptic effects of phenobarbital (PB) in neonatal rodents. In a neonatal cerebral hypoxia-ischemia (HI) model, elicited by right carotid ligation, followed by 90 min 8% O(2) exposure in 7-d-old (P7) rats, PB increases the neuroprotective efficacy of hypothermia (HT). We evaluated whether BUM influenced the neuroprotective efficacy of combination treatment with PB and HT.P7 rats underwent HI lesioning; 15 min later, all received PB (30 mg/kg), and 10 min later, half received BUM (10 mg/kg, PB-HT+BUM) and half received saline (PB-HT+SAL). One hour after HI, all were cooled (30 °C, 3 h). Contralateral forepaw sensorimotor function and brain damage were evaluated 1-4 wk later.Forepaw functional measures were close to normal in the PB-HT+BUM group, whereas deficits persisted in PB-HT+SAL controls; there were corresponding reductions in right cerebral hemisphere damage (at P35, % damage: PB-HT+BUM, 21 ± 16 vs. 38 ± 20 in controls).These results provide evidence that NKCC1 inhibition amplifies PB bioactivity in the immature brain and suggest that coadministration of PB and BUM may represent a clinically feasible therapy to augment the neuroprotective efficacy of therapeutic HT in asphyxiated neonates.
| S-EPMC4721236 | biostudies-literature
Project description:The only validated treatment to prevent brain damage associated with hypoxia-ischemia (HI) encephalopathy of the newborn is controlled hypothermia with limited benefits. Additional putative neuroprotective drug candidates include sildenafil citrate, a phosphodiesterase-type 5 inhibitor. The main objective of this preclinical study is to assess its ability to reduce HI-induced neuroinflammation, in particular through its potential effect on microglial activation. HI was induced in P10 Sprague–Dawley rats by unilateral carotid permanent artery occlusion and hypoxia (HI), and treated by either hypothermia (HT) alone, Sildenafil (Sild) alone or combined treatment (SildHT). Lesion size, glial activation were analyzed by immunohistochemistry, qRT-PCR and proteomic analyses performed at P13. Exposure to any treatment was not associated with significant reduction in lesions size both in cerebral cortex and hippocampus, 72h after HI. Significant reductions in either Iba1+ (within the ipsilateral hemisphere) or GFAP+ cells (within the ipsilateral hippocampus) were observed in SildHT group, but not in the other treatment groups. In microglia sorted cells, pro-inflammatory markers, ie. Il1b, Il6, Nos2, and CD86 were significantly downregulated in SildHT treatment group only. These changes were restricted to ipsilateral hemisphere, were not evidenced in sorted astrocytes, and were not sex-dependent. Proteomic analyses in sorted microglia refined the pro-inflammatory effect of HI and confirmed a biologically relevant impact of SildHT on specific molecular pathways including notably genes related to neutrophilic functions. Our findings demonstrate that Sildenafil combined with controlled hypothermia confers maximum effect to mitigate microglial activation induced by HI through complex proteomic regulation. The reduction of neuroinflammation induced by Sildenafil may represent an interesting therapeutic strategy for neonatal neuroprotection.
2024-04-30 | PXD045168 | Pride
Project description:Approximately half of moderate to severely hypoxic-ischemic (HI) newborns do not respond to hypothermia, the only proven neuroprotective treatment. N-acetylcysteine (NAC), an antioxidant and glutathione precursor, shows promise for neuroprotection in combination with hypothermia, mitigating post-HI neuroinflammation due to oxidative stress. As mechanisms of HI injury and cell death differ in males and females, sex differences must be considered in translational research of neuroprotection. We assessed the potential toxicity and efficacy of NAC in combination with hypothermia, in male and female neonatal rats after severe HI injury. NAC 50mg/kg/d administered 1h after initiation of hypothermia significantly decreased iNOS expression and caspase 3 activation in the injured hemisphere versus hypothermia alone. However, only females treated with hypothermia +NAC 50mg/kg showed improvement in short-term infarct volumes compared with saline treated animals. Hypothermia alone had no effect in this severe model. When NAC was continued for 6 weeks, significant improvement in long-term neuromotor outcomes over hypothermia treatment alone was observed, controlling for sex. Antioxidants may provide insufficient neuroprotection after HI for neonatal males in the short term, while long-term therapy may benefit both sexes.
| S-EPMC4903952 | biostudies-literature
Project description:Delayed hippocampal injury and memory impairments follow neonatal hypoxia-ischemia (HI) despite the use of therapeutic hypothermia (TH). Death of hippocampal pyramidal cells occurs acutely after HI, but characterization of delayed cell death and injury of interneurons (INs) is unknown. We hypothesize that injury of INs after HI is: (i) asynchronous to that of pyramidal cells, (ii) independent of injury severity, and (iii) unresponsive to TH. HI was induced in C57BL6 mice at p10 with unilateral right carotid ligation and 45?min of hypoxia (FiO2 ?=?0.08). Mice were randomized to normothermia (36?°C, NT) or TH (31?°C) for 4?hr after HI and anesthesia-exposed shams were use as controls. Brains were studied at 24?hr (p11) or 8 days (p18) after HI. Vglut1, GAD65/67, PSD95, parvalbumin (PV) and calbindin-1 (Calb1) were measured. Cell death was assessed using cresyl violet staining and TUNEL assay. Hippocampal atrophy and astroglyosis at p18 were used to assess injury severity and to correlate with number of PV?+?INs. VGlut1 level decreased by 30% at 24?hr after HI, while GAD65/67 level decreased by ?50% in forebrain 8 days after HI, a decrease localized in CA1 and CA3. PSD95 levels decreased in forebrain by 65% at 24?hr after HI and remained low 8 days after HI. PV?+?INs increased in numbers (per mm2 ) and branching between p11 and p18 in sham mice but not in NT and TH mice, resulting in 21-52% fewer PV?+?INs in injured mice at p18. Calb1 protein and mRNA were also reduced in HI injured mice at p18. At p18, somatodendritic attrition of INs was evident in all injured mice without evidence of cell death. Neither hippocampal atrophy nor astroglyosis correlated with the number of PV?+?INs at p18. Thus, HI exposure has long lasting effects in the hippocampus impairing the development of the GABAergic system with only partial protection by TH independent of the degree of hippocampal injury. © 2018 Wiley Periodicals, Inc.
| S-EPMC6432630 | biostudies-literature
Project description:BackgroundHypoxic-ischemic encephalopathy (HIE) is a major cause of morbidity in survivors. Therapeutic hypothermia (TH) is the only available intervention, but the protection is incomplete. Preclinical studies of HIE/TH in the rodent have relied on the postnatal day (P) 7 rat whose brain approximates a 32-36 wk gestation infant, less relevant for these studies. We propose that HIE and TH in the term-equivalent P10 rat will be more translational.MethodsP10-11 rat pups were subjected to unilateral hypoxia-ischemia (HI) and 4 h recovery in normothermic (N) or hypothermic (TH) conditions. Brain damage was assessed longitudinally at 24 h, 2 wk, and 12 wk. Motor function was assessed with the beam walk; recognition memory was measured by novel object recognition.ResultsNeuroprotection with TH was apparent at 2 and 12 wk in both moderately and severely damaged animals. TH improved motor function in moderate, but not severe, damage. Impaired object recognition occurred with severe damage with no evidence of protection of TH.ConclusionThis adaptation of the immature rat model of HI provides a reproducible platform to further study HIE/TH in which individual animals are followed up longitudinally to provide a useful translational preclinical model.
| S-EPMC4543535 | biostudies-literature
Project description:Hippocampal injury following neonatal hypoxia-ischemia (HI) leads to memory impairments despite therapeutic hypothermia (TH). In the hippocampus, the expression of calbindin-1 (Calb1), a Ca2+-buffering protein, increases during postnatal development and decreases with aging and neurodegenerative disorders. Since persistent Ca2+ dysregulation after HI may lead to ongoing injury, persistent changes in hippocampal expression of Calb1 may contribute to memory impairments after neonatal HI. We hypothesized that, despite TH, neonatal HI persistently decreases Calb1 expression in the hippocampus, a change associated with memory deficits in the mouse. We induced cerebral HI in C57BL6 mice at postnatal day 10 (P10) with right carotid ligation and 45 min of hypoxia (FiO2 = 0.08), followed by normothermia (36°C, NT) or TH (31°C) for 4 h with anesthesia-shams as controls. Nissl staining and glial fibrillary acidic protein (GFAP) immunohistochemistry (IHC) were used to grade brain injury and astrogliosis at P11, P18, and P40 prior to the assessment of Calb1 expression by IHC. The subset of mice followed to P40 also performed a memory behavior task (Y-maze) at P22-P26. Nonparametric statistics stratified by sex were applied. In both anterior and posterior coronal brain sections, hippocampal Calb1 expression doubled between P11 and P40 due to an increase in the cornus ammonis (CA) field (Kruskal-Wallis [KW] p < 0.001) and not the dentate gyrus (DG). Neonatal HI produced delayed (P18) and late (P40) deficits in the expression of Calb1 exclusively in the CA field (KW p = 0.02) in posterior brain sections. TH did not attenuate Calb1 deficits after HI. Thirty days after HI injury (at P40), GFAP scores in the hippocampus (p < 0.001, r = -0.47) and CA field (p < 0.001, r = -0.39) of posterior brain sections inversely correlated with their respective Calb1 expression. Both sexes demonstrated deficits in Y-maze testing, including approximately 40% lower spontaneous alterations performance and twice as much total impairment compared to sham mice (KW p < 0.001), but it was only in females that these deficits correlated with the Calb1 expression in the hippocampal CA field (p < 0.05) of the posterior sections. Hippocampal atrophy after neonatal HI also correlated with worse deficits in Y-maze testing, but it did not predict Calb1 deficits. Neonatal HI produces a long-lasting Calb1 deficit in the hippocampal CA field during development, which is not mitigated by TH. Late Calb1 deficit after HI may be the result of persistent astrogliosis and can lead to memory impairment, particularly in female mice.
| S-EPMC6742590 | biostudies-literature
Project description:Background and purposeThe only validated treatment to prevent brain damage associated with hypoxia-ischemia (HI) encephalopathy of the newborn is controlled hypothermia with limited benefits. Additional putative neuroprotective drug candidates include sildenafil citrate, a phosphodiesterase-type 5 inhibitor. The main objective of this preclinical study is to assess its ability to reduce HI-induced neuroinflammation, in particular through its potential effect on microglial activation.MethodsHI was induced in P10 Sprague-Dawley rats by unilateral carotid permanent artery occlusion and hypoxia (HI) and treated by either hypothermia (HT) alone, Sildenafil (Sild) alone or combined treatment (SildHT). Lesion size and glial activation were analyzed by immunohistochemistry, qRT-PCR, and proteomic analyses performed at P13.ResultsNone of the treatments was associated with a significant early reduction in lesion size 72h after HI, despite significant changes in tissue loss distribution. Significant reductions in both Iba1 + (within the ipsilateral hemisphere) and GFAP + cells (within the ipsilateral hippocampus) were observed in SildHT group, but not in the other treatment groups. In microglia-sorted cells, pro-inflammatory markers, i.e. Il1b, Il6, Nos2, and CD86 were significantly downregulated in SildHT treatment group only. These changes were restricted to the ipsilateral hemisphere, were not evidenced in sorted astrocytes, and were not sex dependent. Proteomic analyses in sorted microglia refined the pro-inflammatory effect of HI and confirmed a biologically relevant impact of SildHT on specific molecular pathways including genes related to neutrophilic functions.ConclusionsOur findings suggest that Sildenafil combined with controlled hypothermia produces maximum effect in mitigating microglial activation induced by HI through complex proteomic regulation. The reduction of neuroinflammation induced by Sildenafil may represent an interesting therapeutic strategy for neonatal neuroprotection.
| S-EPMC10804557 | biostudies-literature