Estrogen attenuates hypoxic-ischemic brain injury in neonatal rats.
Estrogen is neuroprotective in adult animals. We wished to determine if estrogen protects against brain injury in the newborn. Four-day-old rat pups were treated with subcutaneously implanted pellets containing 0.05 mg (2.4 microg/day) of 17beta-estradiol or vehicle, designed to release the estrogen over 21 days. At 7 days old the pups had the right carotid artery ligated followed by 2.5 h of 8% oxygen. Brain damage was evaluated by weight deficit of the right hemisphere at 22 days following hypoxia. Estradiol treatments reduced brain weight loss from -17.4+/-2.8% S.E.M. in the vehicle group (n=32) to -9.3+/-2.7% in the treated group (n=32, P<0.05). Brain cortex thiobarbituric acid reacting substances and caspase activities were assessed 24 h after reoxygenation. Estradiol significantly reduced a hypoxia-induced increase in brain thiobarbituric acid reactive substances (P<0.05). Levels of caspase-3, -8 and -9 activity increased due to hypoxia-ischemia. Estradiol had no effect on caspase activity. Estradiol reduced brain injury in the neonatal rat.
Feng
Yangzheng
Y
Department of Pediatrics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA.
Fratkins
Jonathan D
JD
LeBlanc
Michael H
MH
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D020169:Caspases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004967:Estrogens / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy* / Q000201:enzymology / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D004967:Estrogens; D020169:Caspases