White matter protection with insulin-like growth factor 1 and hypothermia is not additive after severe reversible cerebral ischemia in term fetal sheep.

Autor:	George S; Department of Physiology, University of Auckland, Auckland, New Zealand., Bennet L, Weaver-Mikaere L, Fraser M, Bouwmans J, Mathai S, Skinner SJ, Gunn AJ
Jazyk:	angličtina
Zdroj:	Developmental neuroscience [Dev Neurosci] 2011; Vol. 33 (3-4), pp. 280-7. Date of Electronic Publication: 2011 Aug 03.
DOI:	10.1159/000329923
Abstrakt:	Moderate cerebral hypothermia significantly improves survival without disability from perinatal hypoxia-ischemia. However, protection is partial. Insulin-like growth factor 1 (IGF-1) plays a key role in oligodendrocyte survival and myelination. The purpose of this study was to test the hypothesis that the combination of IGF-1 plus hypothermia could reduce postischemic white matter damage compared with hypothermia alone. Unanesthetized near-term fetal sheep received 30 min of cerebral ischemia, followed by either an infusion of 3 μg of IGF-1 intracerebroventricularly from 4.5 to 5.5 h plus cooling from 5.5 to 72 h (IGF-1 + hypothermia; n = 8), vehicle infusion plus cooling from 5.5 to 72 h (vehicle + hypothermia; n = 12), sham cooling plus sham infusion (ischemia control; n = 12) or sham ischemia (n = 5). The fetal extradural temperature was reduced from 39.4 ± 0.1°C to between 30 and 33°C. White matter was assessed after 5 days. Ischemia was associated with severe loss of CNPase-positive oligodendrocytes in white matter compared with sham ischemia (380 ± 138 vs. 1,180 ± 152 cells/field; mean ± SD; p < 0.001). Delayed hypothermia reduced cell loss (847 ± 297 cells/field, p < 0.01, vs. ischemia control), but there was no significant difference between vehicle + hypothermia and IGF-1 + hypothermia (1,015 ± 211 cells/field; NS). Ischemia was associated with increased caspase 3 expression in white matter (216 ± 41 vs. 19 ± 18 cells/field; p < 0.001). Hypothermia reduced numbers of activated caspase 3-positive cells (116 ± 81 cells/field; p < 0.05), with no significant difference between vehicle + hypothermia and IGF-1 + hypothermia (91 ± 27 cells/field; NS). In conclusion, delayed cotreatment with IGF-1 plus hypothermia after ischemia was associated with an improvement in white matter damage similar to that achieved by hypothermia alone. (Copyright © 2011 S. Karger AG, Basel.)
Databáze:	MEDLINE
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