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 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 Ã¢ÂÂ 31 weeks), usually due to immature respiratory development. Upregulation of inflammatory genes and pathways in children 7 Ã¢ÂÂ 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 Ã¢ÂÂprogrammingÃ¢ÂÂ 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:Depression is a heterogeneous disorder characterized by a wide range of symptoms, including but not restricted to increased anxiety-like behavior, altered stress responsivity, increased depressive like behavior, decreased pleasure seeking, and altered susceptibility to drugs of abuse. Adding another level of complexity to the disease is the fact that individuals differ in their susceptibility to depression. Research done over the past decade has highlighted the contribution of early life adverse experience to this individual differences in vulnerability to depression. Such studies have been done at the clinical as well as the preclinical level, where rodent and primate models of adverse postnatal environment such as Maternal Separation (MS) are used. MS involves separation of the pup from the dam for 3h every day for the first two weeks of postnatal life. The MS model has been characterized to produce long lasting anxiety-like behavior, depressive behavior and altered stress responsivity in adulthood. While several molecular mechanisms have been hypothesized to mediate the long lasting effects of MS, the serotonin 2a receptor is an attractive candidate, given its role in regulating anxiety-like behavior. So we set out to ask if Maternal Separation alters the 5HT2a responses. In order to assay if MS alters the transcriptional targets of the 5Ht2a receptor, we use a drug that stimulates the 5Ht2a receptor, DOI. The experiment involves injecting both control and MS animals with DOI and looking at the transcriptome induced by DOI under control and MS conditions. This would help understand how the adverse early life experience MS, alters the transcriptional response of an adult rat to stimulation at the 5HT2a receptor, which is physiologically seen in conditions of stress. Maternal Separation (MS) was carried out according to standard protocol. Briefly, upon birth the litters were assigned to either the control or the maternal separation group. Pups from the maternal separation litters were separated from their mother every day for a period of 3 hours from postnatal day 2 (p2) to postnatal day 14 (p14) while the control litters were left undisturbed. After p14, the maternally separated pups were left undisturbed and all litters were weaned at postnatal day 30. Experiments on adult control and MS rats were performed at postnatal day 60. We wanted to ask if a history of adverse experience in early life like MS would alter the transcriptional response of the adult rat to the 5Ht2a agonist DOI. In order to measure the transcriptional changes induced by DOI in control and maternally separated animals, 15 rats (7 - Control and 8 - Maternally Separated) were injected i.p. with either saline or 8 mg/kg DOI. The groups included Control (Control rats injected with saline; n=3), DOI (control rats injected with 8 mg/kg DOI; n=4), MS (MS rats injected with saline, n=4) and MS+ DOI (MS rats injected with 8 mg/kg DOI, n=4). Rats were sacrificed 2 hours after the injection by decapitation. The prefrontal cortex was quickly dissected out and stored at -70 till further use. Total RNA from each rat was extracted, labeled with Cy3 and hybridized onto Agilent Custom Rat Array 8X15K (AMADID: G2509F_16352). Each biological replicate was hybridized onto one array making the total number of arrays 15.

Dataset Information

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure