Neuroscience 2004 Abstract
| Presentation Number: | 919.13 |
|---|---|
| Abstract Title: | Repetitive sublethal hypoxia alters white-matter maturation. |
| Authors: |
Follett, P. L.*1
; Nelligan, J.1
; Volpe, J. J.1
; Jensen, F. E.1
1Neurol., Children's Hosp., Boston, MA |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Developmental Disorders -- Acquired |
| Secondary Theme and Topics | Development<br />- Neurogenesis and Gliogenesis<br />-- Glial differentiation |
| Session: |
919. Developmental Disorders: Sensory and Metabolic Disorders Poster |
| Presentation Time: | Wednesday, October 27, 2004 8:00 AM-9:00 AM |
| Location: | San Diego Convention Center - Hall A-H, Board # EEE29 |
| Keywords: | OLIGODENDROCYTE, AMPA RECEPTOR, MOTOR CONTROL, MYELINATION |
White matter of the preterm brain is highly vulnerable to injury from hypoxia/ischemia and infection. However, while many premature infants experience multiple episodes of hypoxia in the course of neonatal intensive care, the effect of recurrent hypoxia on white matter injury is relatively unexplored. We previously demonstrated that sublethal exposure to hypoxia in the very immature rat at postnatal day (P)3 modifies subsequent AMPA receptor activity in developing oligodendrocytes at P5; and that hypoxia at P3, then repeated at P5, alters subsequent myelin basic protein expression (Follett et al, SFN Abstracts, 2002). Rats subjected to a single episode of hypoxia at either P3 or P5 do not show changes in white matter maturation by immunocytochemistry. In contrast, rats subjected to hypoxia (1h, 6%) at P3 and again at P5 show significantly fewer O1 expressing immature oligodendrocytes in white matter (n=8, p<0.001), as compared with littermate controls (n=6). A mean of 52.3±14.7% of white matter cells express O1 in animals post-hypoxia, as compared to O1+ cells counted in a similar region of stereologically comparable sections in littermate controls. A consistent anterior to posterior decrease in O1+ cells is seen in all animals. We then evaluated whether these changes in white matter maturation have associated motor deficits. Rats were evaluated at P21 with a motorized, accelerating RotaRod test as a sensitive indicator of subtle deficits in rodent motor coordination. RotaRod tests at 5 rpm with 0.1 rpm acceleration demonstrated significant loss of motor performance, by decreased time to drop off in P21 animals following repetitive hypoxia at P3 and at P5 (106±21 seconds, n=9, p<0.03) as compared with littermate controls (129±15 seconds, n=10). These results indicate that repeated sublethal hypoxia injures developing white matter and, importantly, that histological changes appear to correlate with longer-term subtle motor deficits.
Supported by Hood Fnd, NIH HD01359, HD18655, NS38475
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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