Project description:Goal was to determine differences in response to hypoxa-ischemia in the mouse brain at development stages representative of human preterm or term neonates, and to detect putative interference with spontaneous development from 2 to 15 days post-natal. Hypoxia-ischemia was realized in 5-day old and 10 day-old mice by unilateral permanent carotid ligature followed by 40 min oxygen restriction (8%). Ipsilateral hemisphere were collected at 3h, 6h 12h or 24h after hypoxia and pools of sex-equilibrated 4-6 brains were used for total RNA extraction at each time point. Co-hybridization of ishemic mRNA (labelled Cy5) and control tissues (labelled Cy3) were performed on Agilent (design 026655) micro-arrays in three independent experiments. In order to evaluate hypoxia ischemia interference during development, we evaluated spontaneous expression at P5 and P10 (Cy3) and extented the observations in a separate set of tissues extracted at P2 and P15.
Project description:The long-term effects of neonatal intermittent hypoxia (IH), an accepted model of apnea-induced hypoxia, are unclear. We have previously shown lasting âprogrammingâ effects on the HPA axis in adult rats exposed to neonatal IH. We hypothesized that neonatal rat exposure to IH will subsequently result in a heightened inflammatory state in the adult. Rat pups were exposed to normoxia (control) or six cycles of 5% IH or 10% IH over one hour daily from postnatal day 2 â 6. Plasma samples from blood obtained at 114 days of age were analyzed by assessing the capacity to induce transcription in a healthy peripheral blood mononuclear cell (PBMC) population and read using a high-density microarray. The analysis of plasma from adult rats previously exposed to neonatal 5% IH vs. 10% IH resulted in 2,579 significantly regulated genes including increased expression of Cxcl1, Cxcl2, Ccl3, Il1a, and Il1b. We conclude that neonatal exposure to intermittent hypoxia elicits a long-lasting programming effect in the adult resulting in an upregulation of inflammatory-related genes. Apnea is the most common cause of neonatal hypoxia affecting about 50% of preterm births (30 â 31 weeks), usually due to immature respiratory development. Upregulation of inflammatory genes and pathways in children 7 â 10 years of age has been shown, and there is a known increased risk of insulin resistance in adulthood when the fetus is exposed to maternal hypoxia, but the mechanism is unclear. The long-term metabolic, endocrine, and immunological effects of neonatal intermittent hypoxia (IH) exposure, an accepted model of apnea-induced hypoxia, have not been thoroughly evaluated. Recent studies in rats have shown that perinatal IH exposure can result in oxidative stress, causing a permanent immune response subsequently resulting in features of diabetes mellitus. We have previously examined adult rats exposed to neonatal intermittent hypoxia and perinatal continuous hypoxia, and have found lasting âÂÂprogrammingâ effects on the HPA axis. We now assess the long term effects of an accepted model of apnea-induced hypoxia using a validated transcriptional bioassay to study the extracellular milieu of adult rats exposed to neonatal intermittent hypoxia. We hypothesize that exposure to neonatal intermittent hypoxia will result in an increased inflammatory state in the adult as a result of long-lasting programming. Sprague-Dawley (SD) rat pups were treated with neonatal normoxia (21% O2, control), 5% intermittent hypoxia (IH), or 10% IH on postnatal days (PD) 2-6, daily over 1 hr. They were reared normally by birth dams and weaned at PD22. Males were allowed to mature and sacrificed at age PD114 after an overnight fast. Whole blood collected by decapitation into tubes with EDTA, and plasma saved for further analysis. Two adult (~180 day) male Brown Norway (BN) rats served as PBMC donors. Cells were incubated with 20% plasma that was either autologous BN (self-control), or one of 3 pools: a) SD normoxic N=8, b) SD 5% IH treated N=5, and c) SD 10% IH N=3.
Project description:The long-term effects of neonatal intermittent hypoxia (IH), an accepted model of apnea-induced hypoxia, are unclear. We have previously shown lasting “programming” effects on the HPA axis in adult rats exposed to neonatal IH. We hypothesized that neonatal rat exposure to IH will subsequently result in a heightened inflammatory state in the adult. Rat pups were exposed to normoxia (control) or six cycles of 5% IH or 10% IH over one hour daily from postnatal day 2 – 6. Plasma samples from blood obtained at 114 days of age were analyzed by assessing the capacity to induce transcription in a healthy peripheral blood mononuclear cell (PBMC) population and read using a high-density microarray. The analysis of plasma from adult rats previously exposed to neonatal 5% IH vs. 10% IH resulted in 2,579 significantly regulated genes including increased expression of Cxcl1, Cxcl2, Ccl3, Il1a, and Il1b. We conclude that neonatal exposure to intermittent hypoxia elicits a long-lasting programming effect in the adult resulting in an upregulation of inflammatory-related genes. Apnea is the most common cause of neonatal hypoxia affecting about 50% of preterm births (30 – 31 weeks), usually due to immature respiratory development. Upregulation of inflammatory genes and pathways in children 7 – 10 years of age has been shown, and there is a known increased risk of insulin resistance in adulthood when the fetus is exposed to maternal hypoxia, but the mechanism is unclear. The long-term metabolic, endocrine, and immunological effects of neonatal intermittent hypoxia (IH) exposure, an accepted model of apnea-induced hypoxia, have not been thoroughly evaluated. Recent studies in rats have shown that perinatal IH exposure can result in oxidative stress, causing a permanent immune response subsequently resulting in features of diabetes mellitus. We have previously examined adult rats exposed to neonatal intermittent hypoxia and perinatal continuous hypoxia, and have found lasting “programming” effects on the HPA axis. We now assess the long term effects of an accepted model of apnea-induced hypoxia using a validated transcriptional bioassay to study the extracellular milieu of adult rats exposed to neonatal intermittent hypoxia. We hypothesize that exposure to neonatal intermittent hypoxia will result in an increased inflammatory state in the adult as a result of long-lasting programming.
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.
Project description:NRVMs were subjected to varying durations of ischemia or ischemia+reperfusion using coverslip hypoxia. Expression profiling was used to identify genes that are differentially regulated in either event. We used microarrays to detail the global program of gene expression underlying ischemia and reperfusion using Coverslip Hypoxia and identified distinct classes of genes regulated during these processes. Experiment Overall Design: RNA was extracted from NRVMs subjected to varying durations of ischemia or ischemia+reperfusion and hybridized to rat genome Affymetrix arrays.
Project description:NRVMs were subjected to varying durations of ischemia or ischemia+reperfusion using coverslip hypoxia. Expression profiling was used to identify genes that are differentially regulated in either event. We used microarrays to detail the global program of gene expression underlying ischemia and reperfusion using Coverslip Hypoxia and identified distinct classes of genes regulated during these processes. Keywords: time course
Project description:Hypoxia-ischemia (HI) brain damage is one of the most common causes of neonatal brain injuries, amidst other conditions such as intrauterine infection and perinatal cerebral hemorrhage (Bracci et al., 2006). HI, occurring during the perinatal period, severely affects brain integrity resulting in detrimental long-term neurological morbidity in terms of motor, intellectual, educational and neuropsychological performance deficits (e.g. cerebral palsy, mental retardation, learning disability and epilepsy), and even neonatal mortality (Cowan et al., 2003; Ferriero, 2004; van Handel et al., 2007; Shalak and Perlman, 2004). Current therapeutic interventions fail to provide substantial reversal of HI brain injuries and improvement in overall cognitive function. Recent clinical studies demonstrated that post-HI hypothermia provide moderate neuroprotection but fail to show any significant reduction in neonatal morbidity and mortality (Shankaran et al., 2005). We would like to investigate the transcriptional effects of HI on neonatal brain, and if hypoxic pre-conditioning is beneficial to the reduction of brain damage.
Project description:Hypoxia-ischemia (HI) brain damage is one of the most common causes of neonatal brain injuries, amidst other conditions such as intrauterine infection and perinatal cerebral hemorrhage (Bracci et al., 2006). HI, occurring during the perinatal period, severely affects brain integrity resulting in detrimental long-term neurological morbidity in terms of motor, intellectual, educational and neuropsychological performance deficits (e.g. cerebral palsy, mental retardation, learning disability and epilepsy), and even neonatal mortality (Cowan et al., 2003; Ferriero, 2004; van Handel et al., 2007; Shalak and Perlman, 2004). Current therapeutic interventions fail to provide substantial reversal of HI brain injuries and improvement in overall cognitive function. Recent clinical studies demonstrated that post-HI hypothermia provide moderate neuroprotection but fail to show any significant reduction in neonatal morbidity and mortality (Shankaran et al., 2005). We would like to investigate the transcriptional effects of HI on neonatal brain, and if hypoxic pre-conditioning is beneficial to the reduction of brain damage.
Project description:Hypoxia-ischemia (HI) brain damage is one of the most common causes of neonatal brain injuries, amidst other conditions such as intrauterine infection and perinatal cerebral hemorrhage (Bracci et al., 2006). HI, occurring during the perinatal period, severely affects brain integrity resulting in detrimental long-term neurological morbidity in terms of motor, intellectual, educational and neuropsychological performance deficits (e.g. cerebral palsy, mental retardation, learning disability and epilepsy), and even neonatal mortality (Cowan et al., 2003; Ferriero, 2004; van Handel et al., 2007; Shalak and Perlman, 2004). Current therapeutic interventions fail to provide substantial reversal of HI brain injuries and improvement in overall cognitive function. Recent clinical studies demonstrated that post-HI hypothermia provide moderate neuroprotection but fail to show any significant reduction in neonatal morbidity and mortality (Shankaran et al., 2005). We would like to investigate the transcriptional effects of HI on neonatal brain, and if hypoxic pre-conditioning is beneficial to the reduction of brain damage. Microarray analysis was performed on the cortex of neonatal brains using Illumina mouse Ref8 V2 genechips. The right common carotid artery was exposed through a ventral midline neck incision and permanently occluded by electrocoagulation, The wound was sutured and mouse pups were returned to their mother for 1.5M-bM-^@M-^S2 h. Sham control and pre-conditioned mice (n = 4) underwent the identical procedure, without carotid artery occlusion. Pups were then placed in an 8% O2/92% N2 humidified chamber at 37M-BM-0C for 1 h with tissue extraction taking place 3h, 8h and 24h thereafter (n=4 respectively). Sham controls were included in this study too (n=4 respectively).
Project description:Hypoxia-ischemia (HI) brain damage is one of the most common causes of neonatal brain injuries, amidst other conditions such as intrauterine infection and perinatal cerebral hemorrhage (Bracci et al., 2006). HI, occurring during the perinatal period, severely affects brain integrity resulting in detrimental long-term neurological morbidity in terms of motor, intellectual, educational and neuropsychological performance deficits (e.g. cerebral palsy, mental retardation, learning disability and epilepsy), and even neonatal mortality (Cowan et al., 2003; Ferriero, 2004; van Handel et al., 2007; Shalak and Perlman, 2004). Current therapeutic interventions fail to provide substantial reversal of HI brain injuries and improvement in overall cognitive function. Recent clinical studies demonstrated that post-HI hypothermia provide moderate neuroprotection but fail to show any significant reduction in neonatal morbidity and mortality (Shankaran et al., 2005). We would like to investigate the transcriptional effects of HI on neonatal brain, and if hypoxic pre-conditioning is beneficial to the reduction of brain damage. Microarray analysis was performed on the striatum of neonatal brains using Illumina mouse Ref8 V2 genechips. The right common carotid artery was exposed through a ventral midline neck incision and permanently occluded by electrocoagulation, The wound was sutured and mouse pups were returned to their mother for 1.5M-bM-^@M-^S2 h. Sham control and pre-conditioned mice (n = 4) underwent the identical procedure, without carotid artery occlusion. Pups were then placed in an 8% O2/92% N2 humidified chamber at 37M-BM-0C for 1 h with tissue extraction taking place 3h, 8h and 24h thereafter (n=4 respectively). Sham controls were included in this study too (n=4 respectively).