Dynamic changes in adenosine monophosphate-activated protein kinase in neonatal rats with hypoxic ischemic encephalopathy / 中华围产医学杂志

ABSTRACT

Objective To determine the dynamic changes in adenosine monophosphate-activated protein kinase (AMPK) in neurons of neonatal rats suffering from hypoxic ischemic brain injury.Methods Twenty-four-hour old and seven-day old neonatal rats were used in this study.A classic primary cortical neuron oxygen glucose deprivation (OGD) model and neonatal rat hypoxic ischemic encephalopathy (HIE) model were employed.Lactic dehydrogenase (LDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were used to evaluate neuron viability and damage.The expression of phosphorylated adenosine monophosphate-activated protein kinase (P-AMPK),phosphorylated activated protein kinase (P-Akt) and Cleaved Caspase-3 in neurons and brain tissue was measured by Western blot at different time points after OGD or HIE.The Student-t test was used for statistical analysis.Results (1) Compared with the control group,LDH levels at 2,4,8 and 24 h after OGD were higher (all P＜0.05) and optical absorption levels of MTT were lower (all P＜0.05).(2) Levels of P-AMPK in the OGD group were higher than those in the control group,and showed a time-dependent increase at 30 min and 2,4,8 and 24 h (all P＜0.05).The expression levels of P-AMPK in the HIE group were higher than those in the control group (0.345 ± 0.038,0.387 ± 0.112 and 0.618 ± 0.075 at 1,3 and 7 days after HIE,and 0.132±0.032 in the control group,all P＜0.05).(3) The levels of P-Akt increased above the control levels at 30 min (0.991 ±0.134 vs 0.304±0.050),reached a maximum level at 2 h (1.183± 0.107),and then gradually declined,whereas the levels of Cleaved Caspase-3 started to increase at 30 min,and remained elevated at 24 h (all P＜0.05).Conclusion Following hypoxic ischemic brain damage,the expression of P-AMPK is significantly increased in both in vivo and in vitro studies in a time-dependent manner.