Neuroprotection Of CaMKⅡγ And CaMKⅡδ Through PI3K/Akt/Erk Signaling Pathway During Ischemic Reperfusion Injury

OBJECTIVE To observe the effects of Ca2+/calmodulin-dependent kinaseⅠ(CaMKⅡ)γ and CaMkⅡδ on the neuronal acute ischemic reperfusion injury of murine,and the neuroprotective mechanisms involved.METHODS Embryonic day 18 wild type Sprague Dawley rat pups were used for primary neuron culture under 5%CO2,37℃.While inoculating the cells,the five groups were transfected with si-NT,si-CAMK2G-1,si-CAMK2G-2,si-CAMK2D1,si-CAMK2D2,respectively,and then subjected to in vitro ischemia by oxygen-glucose deprivation followed by reoxygenation(OGD/R)for 1 hour and regained the original culture conditions.The survival rate of neuronal cells between groups was evaluated by Calcein-AM and propidium iodide staining,and the expression of phosphatidylinositol-3-kinase/protein kinase B/extracellular signal-regulated kinase(PI3K/Akt/Erk)signaling pathway components were detected by Western blot.Meanwhile,the in vivo animal model of the mouse left middle cerebral artery occlusion(MCAO)model was used to induce the transient focal cerebral ischemia for certification.RESULTS 1.MCAO increased expression of CaMKⅡS and CaMKⅡγ and activated PI3K/Akt/Erk signaling pathway.The expression of Erk,phospho Erk,Akt and phospho Akt(ser473)were up-regulated at 24,48,72 and 96h after MCAO.2.Compared with neuron cells transfected with non-targeted siRNA,knocking down CaMKⅡγ significantly reduced the survival rate of rat neural cells.3.Knockdown CaMKⅡγ or CaMKⅡδ inhibited the upregulation of PI3K/Akt/Erk signaling expression.Compared with neuronal cells transfected with si-CaMK2G and si-CaMK2D,the upregulation of Erk,Phospho-Erk,Akt,and Phospho-Akt(Ser473)was significantly inhibited.CONCLUSION The neuroprotective effects of CaMKⅡγ and CaMKⅡδduring ischemia reperfusion injury may be mediated by PI3K/Akt/Erk signaling pathway.