Neuro-protection of Encapsulated Curcumine on ischemia-reperfusion injury through Attenuating Autophagic and Apoptosis in vitro and in vivo

Abstract

Recently,several breakups had been made for the treatment of cerebral infarction including I.V. thrombolysis and mechanical endovascular thrombectomy (EVT),which opening occluded arteries rapidly.However,abrupt recovery of blood flow to infarction zone usually leads to ischemia-reperfusion (I-R) injury which discounts the benefit.There is no agent has achieved clinical success in aspect of neuro-protection so far.Autophagy is one of the important ways to maintain cellular homeostasis.Appropriate autophagy protects cells in the condition of ischemia and hypoxia,while over-activatied autophagy followed I-R injury result in apoptosis.Curcumine (CUR) was reported to be a natural inhibitor of autophagy,however,its application was restricted by poor water solubility,short half-life and low concentration in brain.Basing on previous result that nanoparticle based drug delivery enhanced drug localization in the brain,we encapsulated CUR in biodegradable nanoparticles (CUR-NPs) and tested their protection in oxygen-glucose deprivation (OGD) cell model and intraluminal filament transient middle cerebral artery occlusion (tMCAO) rats.Post-conditioning with CUR-NPs via carotid artery administration increased viability and decreased apoptosis of cultured PC12 cells in OGD model.CUR-NPs induced expression of Bcl-1 and p62,while reduced the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin 1 in cultured cells through inhibition of autophagy and apoptosis.With refer to the tMCAO rats,autophagy was markedly induced with the up-regulation of LC3-Beclin 1 and down-regulation of p62 in the reperfusion zone at 12 h following reperfusion and that apoptosis was induced with the elevated expression of apoptotic protein Bax,cleaved Caspase-3 at 24 h following reperfusion.CUR-NPs via carotid artery administration after the onset of reperfusion reduced infarct size and mitigated brain edema and improved neurological deficits compared with the equal amount of CUR-solution.CUR-NPs treatment obviously inhibited the neuronal autophagy in the reperfusion brain by inhibiting the induction of LC3-Beclin 1 and reversing the reduction of p62 simultaneously,and inhibited the neuronal apoptosis by elevating the expression of anti-apoptotic protein Bcl-2 and down-regulating apoptotic protein Bax and cleaved Caspase-3.