Transcranial Direct-current Stimulation Confers Neuroprotection In Rat Cerebral Ischemia-reperfusion Injury Via Regulating Serine Beta-lactamase-like Protein

BackgroundIschemic brain injury is a major cause of mortality and disability.The dysfunction in lipid metabolism leads to neuronal death in ischemic brain injury.Serine beta-lactamase-like protein(LACTB)acts as a key molecular regulator in lipid metabolism and plays a critical role in the lipid metabolism disorders.LACTB is regulated by acute insulin signaling pathways in skeletal muscle.Downregulation of PTEN attenuates ischemic brain injury by preserving the function of GABA(A)R receptors.Moreover,transcranial direct current stimulation(tDCS)is a safe and effective non-invasive treatment.It has been proven that tDCS is an effective modulating appetite control cortical excitability via regulating the lipid metabolism and protein synthesis.Hence,we hypothesize that tDCS exerts neuroprotective effects by modulating the LACTB-related lipid signaling transduction in ischemic brain injury.ObjectivesThe objectives of this study were to investigate the role of LACTB in ischemic brain injury and verify the neuroprotective role of tDCS in ischemic brain injury by regulating the LACTB.MethodsThe middle cerebral artery occlusion(MCAO)model in Sprague Dawley(SD)rats and the oxygen and glucose deprivation(OGD)model in the primary culture cortical neurons have been employed.The volume of cerebral infarction after reperfusion(R)was measured with 2,3,5-triphenyltetrazolium chloride(TTC)staining in the MCAO models,and the cellular vitality of primary culture neurons was determined after OGD/R using the cell proliferation and cytotoxicity(CCK-8)kit and lactate dehydrogenase(LDH)cytotoxicity assay kit.The protein expression of LACTB and phosphatase and tensin homolog(PTEN)were detected by western blot in the I/R tissues and OGD/R cells.To clarify the upstream signaling regulation of LACTB,the PTEN inhibitor,Bpv(pic),and the PTEN agonist,Oroxin B(OB),were administrated post MCAO and OGD in vivo and in vitro,the alteration in LACTB expression was determined by western blot.We further analyzed the modulatory role of insulin on PTEN-LACTB signaling in I/R by administering insulin.The volume of cerebral infarction and neural vitality were determined 24 hours post reperfusion,as well as the protein expression of PTEN and LACTB.Finally,we verified that tDCS’s neuroprotective effects in I/R via activating the insulin and blocking PTEN-LACTB.Results1)The protein expressions of LACTB and PTEN were increased in brain ischemic hemispheric zone tissue after I/R;the protein expressions of LACTB and PTEN were increased in primary culture cortical neurons after OGD/R.2)Blocking the activity of PTEN decreased LACTB expression while activating PTEN promoted LACTB expression.3)Administrating insulin after I/R prevented the protein expressions of PTEN and LACTB from elevating in neurons.4)tDCS exerts neuroprotective effects via the Insulin,PTEN and LACTB after ischemic brain injury.Conclusions1)PTEN-LACTB signaling was upregulated in rat cerebral ischemic reperfusion injury,leading to neurological damage and disability;activating insulin receptors inhibited PTEN-LACTB signaling transduction and conferred neuroprotection;2)tDCS regulates the Insulin,PTEN and LACTB which is an effective neuroprotective intervention to ischemic stroke.