摘要
目的探讨免疫蛋白酶体亚基β5i特异性抑制剂PR-957在心脏缺血/再灌注(I/R)损伤中的作用及机制。方法 32只雄性C57BL/6J小鼠随机分为四组:假手术组、假手术+PR-957组、缺血/再灌注组和缺血/再灌注+PR-957组。在心肌缺血/再灌注前一天皮下注射β5i特异性抑制剂PR-957(12 mg/kg)一次,然后结扎左心室左前降支30分钟再灌注24小时。小鼠处死后采用2,3,5-氯化三苯基四氮唑(TTC)染色观察心肌梗死面积;TUNEL染色检测心肌细胞凋亡情况;Western blot检测心脏组织中钙调神经磷酸酶A(Calcineurin A)蛋白水平。结果与假手术组相比,缺血/再灌注引起心肌中β5i蛋白水平明显降低;而导致梗死面积增大、细胞凋亡数量增多和钙调神经磷酸酶A蛋白水平增高;应用β5i抑制剂PR-957处理后进一步加重了缺血/再灌注引起的这些改变。结论抑制免疫蛋白酶体亚基β5i活性可加重缺血/再灌注引起的心肌损伤,其机制作用部分是通过减少钙调神经磷酸酶A被蛋白酶体降解。
Objective To study the role of immunoproteasome subunit β5i inhibitor PR-957 in regulating myocardial ischemia/ reperfusion （I/R） injury and the underlying mechanism. Methods Thirty-two male wild-type C57BL/6J mice were randomly divided into four groups： Sham; Sham＋PR-957; I/R; I/R＋PR-957. The I/R injury model was established by ligating left coronary artery for 30 minutes and reperfusion for 24 hours. PR-957 （12 mg/kg） or vehicle was administrated by subcutaneously 24 hours before the operation. Myocardial infarct area was measured by using triphenyltetrazolium chloride （TTC） staining; Apoptosis was detected by TUNEL assay; and Calcineurin A protein level was measured by Western blot analysis. Results Compared with Sham group, I/R injury significantly decreased the expression of β5i but increased myocardial infarct area, the number of apoptotic cardiomyocytes and Calcineurin A protein level. Treatment of PR-957 further enhanced these effects. Conclusions Inhibition of immunoproteasome subunit β5i aggravated myocardial I/R injury at least in part through attenuation of Calcineurin A degradation by proteasome.
出处
《中国分子心脏病学杂志》
CAS
2017年第1期1979-1982,共4页
Molecular Cardiology of China
基金
国家自然科学基金重点项目(81330003
81570207)
青年基金项目(81500276)
