Neuroprotective effect of phosphatase and tensin homolog allele activity deleted in chromosome 10 inhibition on neuronal apoptosis after hypoxia-ischemia / 中华实用儿科临床杂志

ABSTRACT

Objective To investigate the mechanisms of neuroprotective roles of phosphatase and tensin homolog allele activity deleted in chromosome 10 (PTEN) inhibition on neuronal apoptosis after hypoxia-ischemia (HI)damage.Methods The cerebral cortical neurons of newbom Sprague-Dawley rats were cultured in vitro.Oxygen and glucose deprivation (OGD) model was established to imitate HI environment in vivo.Neurons were divided randomly into 3 groupscontrol groupneurons were treated with normal medium ; OGD groupneurons were treated with OGD for 3 h followed by reperfusion at 0.5,3.0,6.0,12.0,24.0,48.0 h ; PTEN inhibition groupbefore OGD treatment,neurons were pretreated with PTEN inhibitor,and then the neurons were collected at 24 h after reperfusion.Terminal deoxynucleotidyl transferase-mediated dUTP nick and labeling staining was used to detect the apoptotic cells.Western blot was used to detect the expression of PTEN,p-PTEN,protein kinase B(Akt),p-Akt,synthesis of glucose kinase-3 betal (GSK-3β),p-GSK-3β and myeloid cell ceukemia-1 (Mcl-1).Results 1.As compared with control group,TUNEL positive cells increased after OGD observed by TUNEL staining (P ＜ 0.05).The expression of PTEN was increased,the expressions of p-PTEN,p-Akt,p-GSK-3 β,and Mcl-1 were significantly decreased after OGD (all P ＜ 0.05).However,Akt and GSK-3β remained unchanged at different time points after OGD(all P ＞ 0.05).2.As compared with OGD group,TUNEL positive cells were obviously reduced at 24 h after OGD in PTEN group (P ＜ 0.05).Although total PTEN,Akt,and GSK-3 β were not obviously changed in PTEN group(all P ＞ 0.05),the expressions of p-PTEN,p-Akt,p-GSK-3β,and Mcl-1 were significantly increased after OGD (all P ＜ 0.05).Conclusions HI can induce neuronal apoptosis,and the mechanisms of apoptosis may involve PTEN/Akt/GSK-3β/Mcl-1 pathway.The phosphorylation of Akt and GSK-3β can be increased via PTEN activity inhibition,while the ubiquitination of Mcl-1 would be decreased,and thus reduce the neuronal apoptosis.