2型糖尿病对大鼠心肌缺血再灌注损伤救援激酶信号通路的影响

The influence of diabetic on the role of reperfusion injury salvage kinase pathway

目的探讨2型糖尿病(T2DM)对心肌缺血后适应(ischemic postconditioning,IPO)减轻心肌缺血再灌注损伤作用的影响及可能机制。方法高脂饮食联合STZ诱导制成T2DM大鼠模型,将60只雄性Wistar大鼠随机分为正常大鼠缺血再灌注组(A组)、正常大鼠缺血后适应组(B组)、糖尿病大鼠后适应组(C组)。3组均采用离体大鼠心脏Langendorff灌流方法,全心停灌30min,复灌60min,制成心肌缺血再灌注模型。B、C组在再灌注开始前先给予再灌注10s,全心停灌10s,共6次循环的IPO。免疫组织化学染色及Western印迹法测定心肌磷酸化Akt,磷酸化糖原合成酶激酶(GSK-3β)的表达。结果正常离体大鼠心肌IPO干预后磷酸化Akt及GSK-3β的表达增强;而对T2DM大鼠给予IPO处理后磷酸化Akt及GSK-3β的表达无增强,去磷酸化GSK-3β表达增强。结论IPO对正常大鼠离体心脏缺血再灌注损伤有明确的保护作用,而对T2DM大鼠心肌缺血再灌注损伤无保护作用;其机制可能与糖尿病状态下影响再灌注损伤救援激酶信号通路,导致GSK-3β活性(去磷酸化水平)增高有关。

Objective To elucidate the effects of ischemic postconditioning（IPO） on ischemia/reperfusion（I/R） cardiac and the role of reperfusion injury salvage kinase pathway in type 2 diabetic rats . Methods The type 2 diabetic rats were induced by the intravenous injection of streptozotocin and high caloric diet. Sixty Wistar rats were randomly devided into I/R in nomal rats（A）, IPO in normal rats（B）, IPO in diabetic rats（C） groups. Rats were given for Langendorff isolated heart perfusion with 30 min of globe ischemia and 60 min of reperfusion, then the models of group A were made. But the rat hearts of group B and C were subjected to 6 cycles of 10 min of globe ischemia and 10 min of reperfusion as IPO during the early minutes of reperfusion. Phosphorylation of akt and gsk-3β were analyzed by Western blot and immunohistochemical staining. Results The phospho-akt and phospho-gsk-3β expressions were increased markedly in B group. But compared those in A group there was no difference in C group. The phospho-akt and phospho-gsk-3β expressions in C group were more less than those in B group. Conclusions IPO may significantly protect myocardium in isolated normal rat hearts . But in diabetic rats, the protection of IPO has no effect, the mechanism of this phenominon maybe related to gsk-3β in the condition of diabetic.