Tauroursodeoxycholic acid attenuates neuronal apoptosis via the TGR5/ SIRT3 pathway after subarachnoid hemorrhage in rats

BACKGROUND: Neuronal apoptosis plays a critical event in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). This study investigated the roles of Tauroursodeoxycholic acid (TUDCA) in attenuate neuronal apoptosis and underlying mechanisms after SAH. METHODS: Sprague-Dawley rats were subjected to model of SAH and TUDCA was administered via the internal carotid injection. Small interfering RNA (siRNA) for TGR5 were administered through intracerebroventricular injection 48 h before SAH. Neurological scores, brain water content, Western blot, TUNEL staining and immunofluorescence staining were evaluated. RESULTS: TUDCA alleviated brain water content and improved neurological scores at 24 h and 72 h after SAH. TUDCA administration prevented the reduction of SIRT3 and BCL-2 expressions, as well as the increase of BAX and cleaved caspase-3.Endogenous TGR5 expression were upregulated after SAH and treatment with TGR5 siRNA exacerbated neurological outcomes after SAH and the protective effects of TUDCA at 24 h after SAH were also abolished by TGR5 siRNA. CONCLUSIONS: Our findings demonstrate that TUDCA could attenuated neuronal apoptosis and improve neurological functions through TGR5/ SIRT3 signaling pathway after SAH. TUDCA may be an attractive candidate for anti-apoptosis treatment in SAH.

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

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.