Role of ERS in Astragaloside Ⅳ-induced cardioprotection against ischemia/reperfusion injury in rats / 中国药理学通报

ABSTRACT

Aim To explore the role of endoplasmic re-ticulum stress( ERS) in Astragaloside Ⅳ-induced car-dioprotection against ischemia/reperfusion injury in rats. Methods A model of myocardial ischemia 30 min followed by 120 min reperfusion was made by liga-ting coronary artery in male Wistar rats. Rats were di-vided randomly into 4 groups: sham group, ischemia/reperfusion group, ERS inhibitor TUDCA group, As-tragaloside Ⅳgroup. Myocardial samples were collect-ed from the risk zones during ischemia and reperfu-sion, ERS was determined by measuring levels of glu-cose regulated protein 78 ( GRP78 ) , an established marker of ERS with Western blot. Immunofluorescence study was used to test GRP78 intensity with laser scan-ning confocal microscopy, TTC method was used to measure the infarct size,hematoxylin-eosin staining was used to observe the changes of morphological changes of myocardium. Results There was no statistical difference in GRP78 expression during ischemia com-pared to the sham group, but was markedly increased upon reperfusion. Astragaloside Ⅳ could mimic TUD-CA and significantly decreased the GRP78 expression, reduced infarct size and improved the morphology of myocardial tissue with a significant statistical difference compared with the control group ( P<0. 05 ) . Conclu-sions ERS is induced upon reperfusion but not during ischemia in isolated rat hearts. Astragaloside Ⅳ pre-vents myocardial reperfusion injury presumably by the inhibition of ERS.