Peroxisome proliferator-activated receptor γ nuclear translocation induced by focal cerebral ischemia-reperfusion in rats / 中华神经科杂志

ABSTRACT

objective To examine nuclear transIocation of peroxisome proliferator-activated receptor γ(PPARγ)in rats following focal cerebral ischemia/reperfusion(I/R),and to explore the significance of altered PPARγ,nuclear translocation in ischemic brain injury.Methods Healthy adult male SD rats underwent 60-min cerebral artery occlusion followed by reperfusion of 4,8,or 24 h,respectively.The cytoplasmic-to-nuclear shuttling of PPARγ was characterized by Western blot,immunohistochemical and immunofluoreseence staining.The effects of PPARγ agonist rosiglitazone (Ros) and antagonist GW9662 on I/R-induced PPARγ nuclear translocation were also examined in the present study. Furthermore,TTC staining war adopted to determine the change in cerebral infarction volume. Results (1)Western blot analysis revealed an increase of PPARγ in the nucleus and a simultaneous reduction in the cytosol following ischemia and reperfusion for 4 h(tcytosol=9.03,tmuclear=27.19,P=0.00).Prolonged the reperfusion further enhanced this I/R induced PPARγ translocation in a time-dependent manner.Using immunohistochemistry and immunofluorescence,nuclear PPAR γ positive staining increased from 48.3%in the sham control to 80.3% following ischemia and reperfusion for 24 h.(2)Western blot analysis revealed that PPARγ agonist Ros further increased I/R-induced nuclear enrichment of PPARγ,whereas PPARγ antagonist GW9662inhibited I/R-stimulated change in PPARγ.(3)When compared to the L/R group using TTC staining,Ros treatment significantly decreased the infarction volume by 48.40%(15.46±4.94 versus 29.96±3.39,t=5.93.P=0.00),whereas GW9662 increased by 58.95%(47.62±4.93 versus 29.96±3.39,t=7.23,P=0.00).Conclusions Cerebral I/R injury induces PPARγ translocation from the cytosol to the nucleus.This change may represent an intrinsic neuroprotective response against brain I/R injury.