[Effect of cerebral mild hypothermia on cerebral mitochondrial ATPase activity in neonatal rats with hypoxic-ischemic brain damage].
OBJECTIVE
To study the effect of cerebral mild hypothermia on cerebral mitochondrial ATPase activities in neonatal rats with hypoxic-ischemic brain damage (HIBD).


METHODS
Eighty-four seven-day-old Wistar rats were randomly assigned into four groups: sham-operated normothermic, sham-operated mild hypothermic, HIBD normothermic and HIBD mild hypothemic. HIBD was induced by left common carotid artery ligation, followed by 8% hypoxia exposure. At each time interval of 2, 6, and 12 hrs post-hypoxia-ischemia (HI), 7 rats were sacrificed and the brain tissues were sampled for detecting the activities of mitochondrial Na+K+ATPase and Ca2+ATPase.


RESULTS
The activities of mitochondrial Ca2+ATPase decreased significantly in the two HIBD groups compared with those of the two sham-operated groups at 2, 6, and 12 hrs post-HI. The HIBD mild hypothemic group had higher mitochondrial Ca2+ATPase activities compared with the HIBD normothermic group at 2, 6, and 12 hrs post-HI (5.25 +/- 0.61 micromol/mgPr.h vs 3.17 +/- 0.81 micromol/mgPr.h 4.59 +/- 0.81 micromol/mgPr.h vs 2.26 +/- 0.53 micromol/mgPr.h4.61 +/- 0.62 micromol/mgPr.h vs 1.31 +/- 0.78 micromol/mgPr.H, respectively) (P < 0.01). The activities of mitochondrial Na+K+ATPase decreased significantly in the two HIBD groups compared with those of the two sham-operated groups at 6 and 12 hrs post-HI. A significant difference was observed in the mitochondrial Na+K+ATPase activities between the HIBD mild hypothemic and HIBD normothermic groups at 6 and 12 hrs post-HI (5.25 +/- 0.66 micromol/mg Pr.h vs 3.76 +/- 0.78 micromol/mgPr.h, 4.74 +/- 0.80 micromol/mgPr.h vs 3.12 +/- 0.53 micromol/mgPr.h; P < 0.01).


CONCLUSIONS
Mild hypothermia following HIBD inhibits the decline in cerebral mitochondrial Ca2+ and Na+K+ ATPase activities in neonatal rats, thus providing protective effects against HIBD.
Yao
Li
L
Department of Pediatrics, Second Affiliated Hospital of Harbin Medical University, Harbin 150086, China. yaoli_1946@163.com
Cheng
Lin
L
Yu
Li-Jun
LJ
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000201:enzymology*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D005260:Female; D007036:Hypothermia, Induced; D020925:Hypoxia-Ischemia, Brain / Q000201:enzymology / Q000628:therapy*; D008297:Male; D008928:Mitochondria / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase