All issues > Volume 47(11); 2004

Original Article

Korean J Pediatr. 2004;47(11):1210-1215. Published online November 15, 2004.

Possible Neuroprotective Role of Exogenous Growth Hormone on Hypoxic-Ischemic Brain Injury in Neonatal Rats

Young Pyo YP Chang¹, Mi Kyung MK Jung¹, Youn Hee YH Jee¹, Jae Ju JJ Cho¹, Soon Bum SB Lee¹, Woo Sung WS Park¹, Jong-Wan JW Kim², Dong Hoon DH Shin³

¹Department of Pediatrics, College of Medicine, Dankook University, Cheoan, Korea
²Department of Biological Sciences, Dankook University, Cheoan, Korea
³Department of Anatomy, College of Medicine, Seoul National University, Seoul, Korea

Correspondence Young Pyo YP Chang ,Email: ychang@dankook.ac.kr

Abstract

Purpose
: This study was performed to evaluate the possible neuroprotective effect of exogenous growth hormone on hypoxic-ischemic brain injury in neonatal rats.
Methods
: After ligation of the right common carotid artery, seven-day old Sprague-Dawley rats(n= 75) were exposed to 8% oxygen for two hours. In a growth hormone(GH)-treated group(n=25), each animal was subcutanously injected by GH(50 mg/kg, Grotrpin , Dong-Ah Pharmacy Co. KOREA) just before exposing to 8% oxygen, and then injected for the next two consecutive days by the same method. In a saline-treated group(n=25), the same amounts of saline were injected instead of GH. Other twenty five animals were sham-operated without hypoxia as a sham control group. The gross morphologic changes of extracted brains at three and seven days after injury were observed, and the ratios of wet and dry weight of each cerebral hemisphere ipsilateral and contralateral to hypoxic-ischemic injury were compared among three groups for evaluating the severity of brain edema. Also, the microscopic changes of cerebral cortex on coronal sections of paraffin-embedded brains were observed at three days after injury by light microscopy.
Results
: The GH injection reduced the severities of gross changes at seven days after HI injury. The brain edemas of ipsilateral cerebral hemispheres to the site of ligation of the right common carotid artery were significantly decreased in GH-treated animals at three days after HI injury, compared to those in saline-treated animals(P<0.05). On light microscopic examination, neurons with pyknosis of nucleus were remarkably reduced on cerebral cortex at three days after hypoxic-ischemic injury by GH treatment.
Conclusion
: Exogenous GH might have a some neuroprotective role in hypoxic-ischemic brain injury of newborn rats.

Keywords :Growth hormone, Hypoxic-ischemic injury, Apoptosis, Brain, Newborn