目的:研究1型糖尿病早期阶段脑损伤的主要病理原因,是否影响线粒体功能及其可能机制。方法:SD大鼠经股静脉单次注射链脲佐菌素(streptozotocin,STZ)诱导高血糖,持续高血糖2个月后,检测外周血、脑脊液及脑组织中葡萄糖、甘油三酯和总胆固醇水平。取大鼠前额皮层,分离线粒体,检测线粒体氧化及抗氧化水平,Western blotting检测腺苷酸活化蛋白激酶(AMP-activated protein kinase,AMPK)磷酸化水平。全脑冰冻切片,Fluo-Jade-C染色检测神经细胞损伤程度。电镜检测皮层锥体细胞自噬-溶酶体变化。结果:1型糖尿病神经损伤主要原因是高血糖,可以导致皮层Fluo-Jade-C阳性细胞增多,线粒体氧化水平升高,抗氧化能力下降,AMPK磷酸化水平下降。同时发现1型糖尿病大鼠皮层锥体细胞自噬体增多,自噬体内包裹有线粒体或线粒体残余。结论:1型糖尿病早期所致的脑损伤,与持续高血糖增加氧化应激,进而损伤线粒体功能有关,伴随有自噬激活。
Accumulating evidence has suggested that the gap junction plays an important role in the determination of cerebral ischemia, but the underlying mechanisms remain to be elucidated. In this study, we assessed the effect of a gap-junction blocker, carbenoxolone （CBX）, on ischemia/reperfusion-induced brain injury and the possible mechanisms. By using the transient cerebral ischemia model induced by occlusion of the middle cerebral artery for 30 min followed by reperfusion for 24 h, we found that pre-administration of CBX （25 mg/kg, intracerebroventricular injection, 30 min before cerebral ischemic surgery） diminished the infarction size in rats. And this was associated with a decrease of reactive oxygen species generation and inhibition of the activation of astrocytes and microglia. In PC12 cells, H202 treatment induced more coupling and apoptosis, while CBX partly inhibited the opening of gap junctions and improved the cell viability. These results suggest that cerebral ischemia enhances the opening of gap junctions. Blocking the gap junction with CBX may attenuate the brain injury after cerebral ischemia/reperfusion by partially contributing to amelioration of the oxidative stress and apoptosis.
Lang ZhangYu-Min LiYu-Hong JingShao-Yu WangYan-Feng SongJie Yin
