J Korean Pediatr Soc.  2003 Oct;46(10):989-995.

The Effect of Postnatal Dexamethasone Treatment on Hypoxic-Ischemic Brain Injury in Neonatal Rats

• Park CR
• Park KP
• Kim HM
• Sohn YK

Abstract

PURPOSE
Dexamethasone is frequently administered to prevent or treat chronic lung disease in human neonates who are also prone to hypoxic-ischemic(HI) insults. Recently, meta-analysis of the follow-up studies reveals a significantly increased odd ratio for the occurrence of cerebral palsy or an abnormal neurologic outcome, and there is conflicting evidence regarding the impact of dexamethasone exposure on HI brain injury. This study was conducted to explore the effect of post-HI dexamethasone administration on neuronal injury in neonatal rats.
METHODS
HI was produced in seven-day-old rats by right carotid artery ligation followed by two hours of 8% oxygen exposure. At the end of HI, the animals were injected intraperitoneally either with dexamethasone(0.5 mg/kg) or saline. Neuronal injury was assessed seven days after the HI by the area of infarction, TUNEL reactivity, Bcl-2 and Bax expression in brain.
RESULTS
Post-insult dexamethasone administration resulted in reduction of weight gain and a higher mortality rate during seven days after HI. Dexamethasone treatment revealed no effect on the size of brain infarction induced by HI. Bax protein expression increased in dexamethasone treated brain but Bcl-2 protein expression and TUNEL reactivity revealed no significant differences between dexamethasone treated and non treated brain. Increased Bax protein expression suggest upregulation of the apoptosis by dexamethasone.
CONCLUSION
The result suggests the adverse role of Post-HI administration of dexamethasone in neonatal HI.

Keyword

Dexamethasone; Hypoxia-ischemia; neonatal rat; Apoptosis; Infarction size

MeSH Terms

Animals
Apoptosis
bcl-2-Associated X Protein
Brain Infarction
Brain Injuries*
Brain*
Carotid Arteries
Cerebral Palsy
Dexamethasone*
Follow-Up Studies
Humans
In Situ Nick-End Labeling
Infant, Newborn
Infarction
Ligation
Lung Diseases
Mortality
Neurons
Oxygen
Rats*
Up-Regulation
Weight Gain
Dexamethasone
Oxygen
bcl-2-Associated X Protein