缺血后处理对于脑缺血再灌注损伤具有保护作用，但分子机制至今未明。脑组织中缝隙连接蛋白（connexin,Cx）表达丰富，细胞间Cx可形成功能性缝隙连接（gap junction，GJ）通道。研究表明（包括课题组前期结果）：缺血再灌注损伤时Cx表达明显增强；缺血后处理对损伤的保护与GJ功能抑制有关，且GJ功能抑制时Src激酶表达显著降低。因此我们推测：缺血再灌注损伤时，神经细胞间可通过GJ传递死亡信号，从而增强细胞凋亡和（或）死亡；而缺血后处理可通过抑制Src激酶，降低缝隙连接功能，从而减轻损伤。本研究拟采用在体缺血再灌注模型，观察后处理中Src激酶的改变，并进一步研究抑制Src激酶对缺血后处理的影响；在离体缺氧复氧损伤模型中，采用工具药和分子生物学方法（过表达、siRNA）改变Src激酶表达，探讨其在脑缺血后处理中的作用及可能机制。本研究将为脑缺血性疾病的防治提供理论依据及潜在的治疗靶点。

Ischemic postconditioning has protective effect on cerebral ischemia/reperfusion injury, but the molecular mechanisms are still not clear. connexin (connexin, Cx) proteins are expressed abundant in brain tissue. Intercellular Cxs can form functional gap junctions (gap junction, GJ) channels. Research(including our previous results) showed that the expression of Cxs was significantly enhanced during ischemia /reperfusion injury. The protective effect of ischemic postconditioning is related to the functional inhibition of GJ, and the expression of Src kinase is reduced when the function of GJ is inhibited. Therefore, we hypothesis that death signal can be transmitted between nerve cells through GJ during ischemia/reperfusion injury, and cells apoptosis and (or) death are enhanced, while ischemic postconditioning can extenuate the damage by reduceing gap junction function through inhibiting Src kinase. In this study, model of in vivo ischemia/reperfusion will be used, the Src kinase change was observed after ischemic postconditioning and the influence of Src kinase inhitbition on ischemic postconditioning will also be further researched. In vitro hypoxia/reoxygen injury model, tool drugs and molecular biology methods (overexpression, siRNA) will be used to change the expression of Src kinase and explore its role and possible mechanisms in cerebral ischemic postconditioning. This study will provide a theoretical basis and potential therapeutic targets for the prevention and treatment of ischemic cerebrovascular disease.

目的：研究Src激酶对缝隙连接功能的调控在脑缺血后处理中的作用及机制。方法：在体实验采用大脑中动脉栓塞法复备大鼠局灶性脑缺血/再灌注损伤的模型及离体实验采用原代培养星形胶质细胞缺氧/复氧损伤模型，观察后处理对大鼠脑组织缺血/再灌注损伤及星形胶质细胞缺氧/复氧的保护作用。在体实验中采用Longa 5分法对大鼠的神经行为学表现进行评分，TTC染反法测定脑梗死体积 并计算脑梗死体积百分率，另取脑组织作HE杂色进行病理学检查；离体实验采用MTT法对星形胶质细胞存活情况进行检测而凋亡情况则采用AnexinV/PI双染流式细胞术及Hoechst33258染色法进行检测，采用荧光示踪法测定星形胶质细胞间的GJ功能；Western blot 法检测大鼠大脑皮层组织及星形胶质细胞Cx43蛋白、Src激酶及凋亡相关蛋白Bax、Bcl-2的表达。结果：与正常大鼠相比，缺血/再灌注损伤大鼠出现明显的神经功能障碍，出现脑组织HE染色病理学改变以及脑组织梗死；缺血后处理可明显降低脑缺血/再灌注损伤引起的大鼠神经功能障碍的评分，减轻病理学改变，降低脑梗死体积百分率。联合使用缝隙连接抑制剂后，缺血后处理的上述保护作用进一步增强。与正常星形胶质细胞相比，缺氧/复氧损伤时星形胶质细胞存活率明显降低，而细胞凋亡率则明显升高；缺氧后处理使缺氧/复氧损伤星形胶质细胞存活率明增加而细胞凋亡率则明显降低。在缺氧后处理的基础上合用了缝隙连接增强剂及缝隙连接抑制剂后，缺氧后处理对缺氧/复氧损伤星形胶质细胞的上述保护作用则分别有所减弱和增强。缺血/再灌注(缺氧/复氧)损伤时Cx 43、Src的表达增加，Bax/ Bcl-2的比值升高，后处理则使该改变减轻。结论：后处理减轻脑缺血/再灌注损伤机理可能与抑制Src激酶，进而抑制GJ功能，减少细胞凋亡有关。　　此外，针对缝隙连接在脑缺血再灌注损伤中的改变开展了相关研究工作，如抑制ADPH氧化酶、全麻药丙泊酚、激动EGF受体对大鼠脑缺血再灌注损伤的影响及其与缝隙连接的关系等。