摘要
目的:探讨锌离子在缺血预处理保护机制中的作用。方法:50只雄性Wistar大鼠随机分为5组(n=10):假手术组(对照组)、缺血再灌注组(I/R组)及缺血预处理组(I/R+IPC组)、缺血预处理加锌离子抑制剂(TPEN)组(I/R+IPC+TPEN组)、缺血再灌注加TPEN组(I/R+TPEN组)。检测各组大鼠心肌组织锌离子水平、心肌梗死面积大小、心肌组织形态学变化、心肌磷酸化蛋白激酶样内质网激酶(p-PERK)和抗氧化应激蛋白质核因子E2相关因子2(Nrf2)表达水平以及细胞凋亡指数(AI)。结果:(1)心肌组织内锌离子水平:心脏再灌注后,I/R组较对照组显著降低,I/R+IPC组则较I/R组显著升高(P均<0.05)。(2)心肌梗死面积比:I/R组较对照组显著增加,I/R+IPC组则较I/R组明显减小,I/R+IPC+TPEN组较I/R+IPC组显著增加(P均<0.05)。(3)与对照组相比,I/R组大鼠心肌组织明显排列紊乱,心肌纤维断裂,而I/R+IPC组大鼠上述现象明显改善,I/R+IPC+TPEN组中IPC的这种作用被TPEN逆转。(4)心肌p-PERK和Nrf2的表达水平:I/R组较对照组均显著升高,I/R+IPC组较I/R组显著降低;I/R+IPC+TPEN组较I/R+IPC组明显升高(P均<0.05)。(5)心肌细胞AI:I/R组显著高于对照组[(35.80±5.31)%vs(5.80±2.86)%],I/R+IPC组[(16.20±4.82)%]显著低于I/R组,I/R+IPC+TPEN组[(32.60±6.03)%]较I/R+IPC组明显升高(P均<0.05)。I/R+TPEN组与I/R组上述各指标间的差异均无统计学意义(P均>0.05)。结论:缺血预处理可能通过锌离子抑制PERK/Nrf2通路,发挥心肌保护作用。
Objectives:To investigate if zinc plays a role in ischemic preconditioning(IPC)-induced cardioprotection in rats.Methods:Fifty male rats(250-350 g)were randomized assigned into control group,I/R group,I/R+IPC group,I/R+IPC+TPEN group,I/R+TPEN group(n=10 each).Cytosolic zinc concentrations were measured with Zinc assay kit;Infarct size was assessed by Evans blue dye and triphenyltetrazolium chloride double staining;Hematoxylin and eosin staining was applied to observe the morphological changes;The expression levels of Nuclear factor erythroid-2 related factor 2(Nrf2)and phosphorylatd PKR-like ER kinase(p-PERK)were detected by Western blotting;Terminal deoxynu-cleotidyl transferase-mediated(dUTP)nick end-labeling(TUNEL)assay was used to analyze the apoptotic index.Results:(1)Compared with control group,Cytosolic zinc concentrations were decreased dramatically in I/R hearts(P<0.05),IPC increased the zinc levels at reperfusion(P<0.05).(2)Infarct size was reduced significantly in IPC group as compared to I/R group,but the effect of IPC was blunted by the selective zinc chelator N,N,N′,N′-tetrakis-(2-pyridylmethyl)ethylenediamine(TPEN)(all P<0.05).(3)Destructive pathological changes in the I/R group could be partly reversed by IPC,this effect could be attenuated by TPEN.(4)Compared with control group,I/R significantly upregulated the expression of p-PERK and Nrf2(P<0.05),while IPC significantly downregulated the expression of p-PERK and Nrf2(P<0.05),which were again reversed by TPEN(P<0.05).(5)Apoptotic index(AI)was significantly increased in the I/R group than in control group([35.80±5.31]%vs[5.80±2.86]%,P<0.05),which was significantly reduced in the IPC group([16.20±4.82]% vs[35.80±5.31]%,P<0.05),this effect could be partly blunted by TPEN([32.60±6.03]%vs[16.20±4.82]%,P<0.05).Conclusions:These results demonstrate that zinc may play an important role in the cardioprotective effect of IPC through inhibiting the PERK/Nrf2 pathway.
作者
温凌娜
田增有
张春来
周洪霞
习瑾昆
WEN Lingna;TIAN Zengyou;ZHANG Chunlai;ZHOU Hongxia;XI Jinkun(School of Clinical Medicine,North China University of Science and Technology,Tangshan(063210),Hebei,China)
出处
《中国循环杂志》
CSCD
北大核心
2019年第11期1110-1116,共7页
Chinese Circulation Journal
