Neonatal hypoxia‐ischemia in rat increases doublecortin concentration in the cerebrospinal fluid

Abstract

Doublecortin (DCX) is a microtubule-associated protein widely used as an indicator of neurogenesis in immunohistochemical analyses of the postmortem adult brain. A recent study reported that DCX can be quantified in the cerebrospinal fluid (CSF) from healthy rats between postnatal day 0 (P0) and P30. However, it is currently unclear whether the concentration of DCX in the CSF (CSF-DCX) may represent a measure of endogenous neurogenesis. To address this question, this study examined the impact of a neonatal hypoxic-ischemic (HI) brain injury, known to induce neurogenesis, on CSF-DCX. HI was elicited at P7 in Sprague-Dawley rat neonates, and CSF was collected serially from the cisterna magna at P5 and P10, or at P10 and P15. A sandwich immunoassay was used to measure CSF-DCX. Brains from P10 neonates were analyzed immunohistochemically for neurogenesis and cell death markers. Mean CSF-DCX was significantly higher in HI- than in sham-exposed animals, at both P10 and P15. In the HI group at P10, CSF-DCX and stroke severity correlated positively. DCX immunoreactivity was increased in the ipsilateral neurogenic niches from the P10 HI brains in comparison with that of shams. The number of proliferative DCX-positive cells was higher in the ipsilateral hippocampal subgranular zone (SGZ) than in the HI contralateral or sham SGZ. Thus, neonatal HI brain injury disrupts the developmental time-course of DCX levels in the CSF. Our data suggest that the increased concentration of DCX in the CSF after neonatal HI is the result of both cellular injury and increased neurogenesis.

Neonatal hypoxia-ischemia in rat elicits a region-specific neurotrophic response in SVZ microglia

“…In comparison, the response in the neonate evolved mainly within 4 weeks and included the contralateral SVZ that was evoked by the combination of hypoxia and ipsilateral ischemic injury, but not by hypoxia alone. An increased neurogenesis in contralateral SVZ has been noted previously after neonatal HI [6,7]. Several potential factors may account for these differences including the injury model, sex distribution, rat strains, and the cell counting method, which in our study considered changes in SVZ size.…”

“…Due to the significant variability in HI injury size in the Rice-Vannucci model of neonatal HIE, two investigators (UF, CB) independently assessed the HI injury size using ImageJ software (version 2.00rc.43/1.50e) and their results were averaged. The size of HI injury was calculated by subtracting the intact area in the right, from here on defined as the ipsilateral hemisphere from the total area of the left, contralateral hemisphere in 3 serial cresyl violet-stained sections as previously described [6]. Animals with no apparent or extensive HI injury that affected the SVZ were excluded in order to compare relatively homogenous groups.…”

“…The rodent model of neonatal hypoxic-ischemic encephalopathy (HI) reflects the key pathomechanisms of HIE in term-born infants and has been shown to be a strong inducer of early postnatal SVZ neurogenesis [6][7][8]. Up to now, there are no clinical therapies available that specifically modulate this induced neurogenesis to amplify repair processes.…”

RBM3 promotes neurogenesis in a niche-dependent manner via IMP2-IGF2 signaling pathway after hypoxic-ischemic brain injury

“…Cerebrospinal fluid (CSF) samples were collected from cisterna magna immediately before sacrificing animals as described previously 50 . NSPC culture media were collected immediately before fixing cells.…”

Distribution Assessments of Coumarins from Angelicae Pubescentis Radix in Rat Cerebrospinal Fluid and Brain by Liquid Chromatography Tandem Mass Spectrometry Analysis

“…A dorsal midline cutaneous incision was made, and the muscle at the craniocervical junction was bluntly dissected to expose the atlanto-occipital membrane. The cisterna magna was punctured with a thin syringe needle, and a microinjector connected with the needle was used to collect the interior CSF carefully [ 27 ]. Clear CSF was transferred to a clean microtube and frozen at −80 °C until further use.…”