Effects of postnatal dexamethasone on blood-brain barrier permeability and brain water content in newborn lambs.
Effects of postnatal dexamethasone on blood-brain barrier permeability and brain water content in newborn lambs.
复制标题
产后地塞米松对新生羔羊血脑屏障通透性和脑含水量的影响。
DOI：
10.1152/ajpregu.2001.280.2.r547
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Stonestreet,BS
中科院分区：
文献类型：
--
作者：
Sysyn,GD;Petersson,KH;Patlak,CS;Sadowska,GB;Stonestreet,BS
We showed that antenatal corticosteroids reduced blood-brain barrier permeability in fetuses at 60 and 80%, but not 90% of gestation, and decreased brain water content in fetuses. Our objective was to examine the effects of postnatal corticosteroids on regional blood-brain barrier permeability and brain water content in newborn lambs. Three dexamethasone treatment groups were studied in 3- to 5-day-old lambs. A 0.01 mg/kg dose was selected to estimate the amount of dexamethasone that might have reached fetuses via antenatal treatment of ewes in our previous studies. The other doses (0.25 and 0.5 mg/kg) were chosen to approximate those used clinically to treat infants with bronchopulmonary dysplasia. Lambs were randomly assigned to receive four intramuscular injections of dexamethasone or placebo given 12 h apart ondays 3and4of age. Blood-brain barrier function was measured with the blood-to-brain transfer constant (Ki) to α-aminoisobutyric acid, brain plasma volume was measured with polyethylene glycol for the calculation ofKi,and brain water was measured by wet-to-dry tissue weights. Postnatal treatment with corticosteroids did not reduce barrier permeability in newborn lambs. Brain blood volume was higher in the 0.25 and 0.5 mg/kg dose dexamethasone groups than in the placebo group. Brain water content did not differ among the groups. We conclude that postnatal treatment with corticosteroids did not reduce regional blood-brain barrier permeability or brain water content but increased the brain plasma volume in newborn lambs. These findings are consistent with our previous work indicating that barrier permeability is responsive to corticosteroids at 60 and 80% of gestation and brain water regulation at 60% of gestation, but not in near-term fetuses or newborn lambs.
