糖尿病患者心脏较非糖尿病患者更不易耐受缺血再灌注损伤（IRI），这与糖尿病心肌PKC-β2过度活化及PI3K/Akt/eNOS通路失活有关，但其调控机制不明。我们前期研究发现，PKC-β2活化后可与心肌细胞Caveolin-3（Cav-3）直接相互作用并对后者发挥负性调控作用，进一步研究发现在单克隆抗体Cav-3的免疫沉淀下，PKC-β2可与Akt形成蛋白复合体。据此申请者推测PKC-β2负性调控Cav-3/PI3K/Akt/eNOS信号通路而加重糖尿病心肌IRI。本项目拟用Cav-3基因敲除小鼠、原代心肌细胞为研究对象，复制糖尿病心肌IRI模型及高糖与缺氧/再复氧模型，并结合腺病毒转染及siRNA技术，试图阐明PKC-β2/Cav-3/PI3K/Akt/eNOS信号轴在糖尿病心肌IRI中的作用机制，以期为临床开发糖尿病心肌IRI保护药物提供实验依据。

Diabetic patients are less tolerant to myocardial ischemia reperfusion injury ( IRI ) as compared to non-diabetic, which may be due to excessive activation of PKC beta 2 and inactivation of PI3K / Akt / eNOS pathway in myocardium. However, its underlying mechanisms are still unknown. In our preliminary studies, we found that the activated PKC beta 2 interacted directly with cardiomyocyte caveolins-3 (Cav-3) and negatively regulated Cav-3 function. Furthermore, with immunoprecipitation of monoclonal antibody Cav-3, we also identified the formation of protein complex of PKC beta 2 and Akt in diabetic myocardium. Therefore, we hypothesize that PKC beta 2 activation exacerbates diabetic myocardial IRI through inhibition of Cav-3 / PI3K /Akt / eNOS signaling pathway. In the current proposal, we will use the selective Cav-3 gene knockout mice and primary cultured cardiomyocytes to make diabetic model or high glucose with hypoxia/reoxygenation treated model, incorporating the use of adenovirus transfection and siRNA technology, to elucidate the role and mechanism of PKC beta 2 / Cav-3 / PI3K / Akt / eNOS signaling pathway in diabetic myocardial IRI. This proposed study will improve our understandings of diabetic myocardial IRI and may help facilitate the development of novel and optimal therapies in diabetic and ischemic heart disease.