J.A. Quinlivan, L.D. Beazley, M. Archer, S.F. Evans, J.P. Newnham, S.A. Dunlop
Repeated prenatal corticosteroids reduce glial fibrillary acidic protein in the ovine central nervous system
Introduction: A single course of corticosteroid reduces
intracranial hemorrhage in preterm infants. The mechanism
of protection is unclear. Glial fibrillary acidic protein
(GFAP), expressed by astrocytes, is regulated by glucosteroids
and is an important component of the cells
forming the blood brain barrier. We have evaluated the
effect of prenatal corticosteroid upon ovine GFAP.
Methods: Date-mated ewes were studied in two protocols
and lambs delivered on day 125 or 145 (term = 150).
In the maternal injection protocol (n = 36) ewes were administered
saline, single or repeated injections of corticosteroid.
In the fetal injection protocol (n = 48) direct
ultrasound-guided fetal injections of saline, single or repeated
corticosteroid were administered, and an additional
control group did not receive fetal injections. Optic
nerve GFAP immunohistochemistry was performed and
quantified.
Results: At 125 days, repeated, but not single, administration
of corticosteroid, by either maternal or fetal route,
was associated with a significant reduction in GFAP
(both p < 0.002); by 145 days, the deficit had recovered
(both p > 0.05). The process of performing repeated fetal
injections had an independent effect upon GFAP at
145 days (p = 0.002).
Conclusion: Repeated administration of corticosteroid
results in a reduction in GFAP in the developing ovine
optic nerve, with recovery demonstrated by 145 days.
Journal of Perinatal Medicine, Walter de Gruyter
Print ISSN: 1619-3997
Volume: 30, 06/2002
Pages: 209 - 219
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