抑制糖原合成酶激酶3活性对Toll样受体4介导肝脏炎症反应的调节作用

目的 研究抑制糖原合成酶激酶3 β (GSK-3 β)活性对Toll样受体4介导的炎症反应的调节作用. 方法 以C57BL/6小鼠为研究对象,分别建立不同灌注时间的小鼠热缺血再灌注损伤模型以及通过腹腔注射脂多糖(LPS)建立小鼠肝脏炎症模型；通过小鼠的股骨分离出骨髓干细胞,经过分化培养获得骨髓来源的巨噬细胞,随后通过LPS激活TLR4配体引发炎症细胞模型.通过SB216763抑制GSK-3β活性,分别干预小鼠肝脏炎症模型和炎症细胞模型.通过Western blot检测肝脏丝裂原活化蛋白激酶的表达；实时定量PCR方法检测细胞炎症因子的基因表达.用SPSS13.0统计软件进行单因素方差分析,用LSD- f检验进行组间比较. 结果 在肝脏缺血再灌注过程中,丝裂原活化蛋白激酶(包括ERK、JNK和p38)的磷酸化水平在灌注1h后增加,ERK、JNK和p38的活性升高,但在4h后,这种活性激活消失,回归到起始水平.此外,LPS刺激巨噬细胞激活ERK、JNK在15 min被磷酸化而激活,p38蛋白在1h左右磷酸化而被激活.SB216763预处理一定程度上抑制了LPS刺激巨噬细胞的ERK、JNK和p38蛋白磷酸化的激活.无论是小鼠肝脏炎症模型还是炎症细胞模型,GSK-3 β活性抑制均促进了抗炎细胞因子白细胞介素10 (IL-10)的表达,而显著抑制了促炎细胞因子IL-12、肿瘤坏死因子(TNF)α,IL-6和IL-1β的基因表达.在对照组、炎症组及SB216763干预组小鼠炎症模型中炎症因子基因表达结果显示,IL-10相对表达量分别为0.21±0.08,0.83±0.21,1.76±0.67,F=3.16,P=0.027;IL-12相对表达量分别为0.11±0.05,0.85±0.11,0.43±0.10,F=2.67,P=0.038；TNFα相对表达量分别为0.052±0.012,8.11 ±0.98, 3.9±0.82,F=4.13,P=0.016; IL-1 β相对表达量分别为0.12±0.07,2.51±0.62,1.28±0.33,F=2.22,P=0.030;IL-6相对表达量分别为0.22±0.08,6.37±0.81,2.11±0.63,F=3.21,P=0.024.结论 抑制GSK-3 β活性选择性地调节肝脏中枯否细胞抗炎和促炎因子的表达从而引起肝脏缺血再灌注损伤的改善,随着促炎细胞因子被抑制,使得炎症反应所诱导的肝细胞凋亡也间接地受到有效控制.     

糖原合成酶激酶-3β在D-GalN/LPS诱导的小鼠急性肝衰竭中的作用

目的:研究细胞信号分子糖原合成酶激酶-3β(glycogen synthase kinase-3β,GSK-3β)在D-氨基半乳糖/脂多糖联合注射诱导小鼠重型肝炎肝衰竭中的作用.方法:以C57BL/6小鼠为研究对象,腹腔注射D-氨基半乳糖/脂多糖建立小鼠重型肝炎肝衰竭模型.动物实验分组:对照组,重型肝炎肝衰竭模型组,SB216763干预组(建模前2h腹腔注射),SB216763治疗组(建模后2h腹腔注射).Western blot检测肝脏组织GSK-3β磷酸化水平,检测血清转氨酶(alanine aminotransferase,ALT)、天门冬酸氨基转移酶(aspartate aminotransferase,AST)评价肝脏功能,观察肝脏组织病理变化评价肝脏损伤情况,实时荧光定量PCR法检测肝脏细胞炎症因子基因表达,并检测凋亡相关蛋白Caspase 3的活性表达.多组样本均数的两两比较采用One-way ANOVA分析(方差齐者用LSD-t检验,方差不齐者用Games-Howell法),P<0.05有统计学意义.结果:Western blot结果显示,GSK-3β在急性肝衰竭过程中磷酸化水平先降低(活性升高)后再次升高;抑制GSK-3β活性,无论是干预还是治疗都改善肝脏功能(血清ALT、AST水平明显下降,肝组织病理损伤明显改善),并且抑制炎症反应[抑制促炎因子肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白介素6(Interleukin-6,IL-6)、IL-1β表达,促进抗炎因子IL-10高表达],并可降低凋亡相关蛋白Caspase 3表达.结论:在D-氨基半乳糖/脂多糖诱导小鼠急性肝衰竭过程中GSK-3β被激活,抑制GSK-3β活性通过降低炎症反应和肝细胞凋亡从而改善肝损伤.因此,对信号分子GSK-3β活性进行干预有可能为重型肝炎肝衰竭的治疗提供一个新的靶点.     

糖原合成酶激酶-3与糖代谢异常的关系

糖原合成酶激酶（glycogen synthase kinase,GSK）-3是表达于各种组织的丝/苏氨酸激酶,最初因其底物是糖原合成酶而得名.现在的研究结果发现,GSK-3具有多种功能,与细胞内糖原代谢、胰岛素信号途径、细胞增殖、神经功能、胚胎发育、肿瘤发生等都有密切的关系.     

抑制糖原合成酶激酶-3β活性减少肝细胞凋亡保护D-氨基半乳糖／脂多糖诱导的小鼠急性肝衰竭损伤

目的：研究细胞信号分子糖原合成酶激酶-3β（glycogen synthase kinase-3β,GSK-3β）对 D-氨基半乳糖／脂多糖（D-GalN／LPS）联合诱导的小鼠急性肝衰竭肝细胞凋亡的影响。方法腹腔注射 D-GalN／LPS 建立小鼠急性肝衰竭模型。实验动物分为对照组、模型组、SB216763干预组（建模前2 h 腹腔注射）。检测血清 ALT、AST,TUNEL 法测定肝细胞凋亡,免疫荧光染色法及比色法检测 Caspase-3活性,Western 印迹检测 Cleaved Caspase-3蛋白表达。多组样本均数的两两比较采用一步法 ANOVA 分析。结果 GSK-3β活性升高促进了在小鼠急性肝衰竭的发生和发展：抑制 GSK-3β活性可以显著改善肝脏功能,血清 ALT、AST 水平明显下降。SB216763干预组 ALT 与 AST 水平分别为（961．1±356．0）IU／L和（2709．9±423．9）IU／L,SB216763干预组与模型组相比,Caspase-3活性降低,TUNEL 方法检测肝细胞凋亡减少,并且Cleaved Caspase-3的蛋白表达降低。结论在 D-GalN／LPS 诱导的小鼠急性肝衰竭中,抑制 GSK-3β活性可能通过抑制肝细胞凋亡而改善肝损伤。因此,对信号分子 GSK-3β活性进行干预有可能为急性肝衰竭的治疗提供一个新的靶点。     

Dynamical changing patterns of glycogen and enzyme histochemical activities in rat liver graft undergoing warm ischemia injury

AIM: To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to warm ischemia injury. METHODS: The rats were randomized into five groups, WIT was 0,15,30,45,60 min, respectively, and histochemical staining of liver graft specimens was observed. The recovery changes of glycogen and enzyme histochemistry activities were measured respectively 6 and 24 h following liver graft implantation. RESULTS: The activities of succinic dehydrogenase, cytochrome oxidase, apyrase (Mg++-ATPase) and content of glycogen were decreased gradually after different WIT in a time-dependent manner. The changes were significant when WIT was over 30 min. CONCLUSION: Hepatic injury is reversible within 30 min of warm ischemia injury. Glycogen and enzyme histochemistry activities of liver grafts and their recovery potency after reperfusion may serve as criteria to evaluate the quality of liver grafts.     

Expression of macrophage inflammatory protein-1αin Kupffer cells following liver ischemia or reperfusion injury in rats

AIM: To explore the expression of macrophage inflammatory protein-la (MlP-1α) in Kupffer cells (KCs) following liver ischemia/reperfusion injury IRI in rats. METHODS: Forty male SD rats were divided randomly into five groups. A model of partial warm ischemia/ reperfusion injury in the rat liver was established. KCs were isolated and incubated one hour, six hours, 12 h, and 24 h after the reperfusion. Tumor necrosis factor alpha (TNF-α) and interleukin-1beta (IL-1β) in the supernatants were measured by ELISA. MIP-1αin KCs was detected by immunocytochemical and RT-PCR. RESULTS: No or few MIP-1αprotein and mRNA were expressed in the KCs of the control group. Its expression in the IRI group had a significant increase after the reperfusion (P < 0.05), which was contrary to the control group. CONCLUSION: The active behavior of the MIP-1αgene in KCs following liver ischemia/reperfusion injury is assumed to be one of the major causes for the hepatic ischemia/reperfusion injury.     

单硝酸异山梨酯注射液通过调控PI3K/AKT/GSK3β通路改善急性心肌缺血大鼠心功能的研究

目的 探讨单硝酸异山梨酯注射液（isosorbide mononitrate injection,ISMI）对急性心肌缺血（acute myocardial ischemia,AMI）大鼠心功能及磷酸肌醇3激酶/蛋白激酶B/糖原合成酶激酶3β(phosphoinositide 3-kinase/protein kinase B/glycogen synthase kinase 3 beta,PI3K/AKT/GSK3β)信号通路的影响。方法 40只SD大鼠随机分为假手术组、AMI模型组、AMI+ISMI组、AMI+PI3K抑制剂组、AMI+ISMI+PI3K抑制剂组，每组8只，冠状动脉结扎法构建AMI大鼠模型，构建成功后各组连续干预14 d。超声心动图检测大鼠心功能指标，多导生理记录仪检测大鼠血液流变学指标，苏木精-伊红染色法（hematoxylin-eosin,HE）染色、Masson染色观察大鼠心肌组织损伤情况，TUNEL法检测大鼠心肌细胞凋亡情况，蛋白质印迹（Western blot,WB）法检测大鼠心肌组织中PI3K/AKT/GSK3β通路蛋白表达。结果 与假手术组相比，AMI...     

Differentiation of bone marrow stem cells into the cardiomyocyte-like cells induced by fetal cardiac supernatant with 6-bromoindirubin-3-oxime

Background Our previous study showed the 150 mg/mL fetal cardiac supernatant (FCS) could induce differentiation of BMSCs into cardiomyocye-like cells without cardiomyocyte touch,but differentiation efficiency is not high enough.Inhibition of glycogen synthase kinase-3 enhanced the proliferation and survives of stem cells.We tested if 6-bromoindirubin-3-oxime (BIO,glycogen synthase kinase-3 inhibitor) enhances the effects of FCS on differentiation of BMSCs and explore the growth factors in FCS.Methods BMSCs were isolated from the femur and tibia of four-week-old male Sprague-Dawley rats and co-cultured with FCS (150 mg/mL) that was made from fetal hearts from nineteen-day pregnant Wistar rats.BIO with different concentration (0,1,10,and 100 nM) was introduced in culture dishes.Transforming growth factor beta 1 (TGF-β1),bone morphogenetic protein 2 (BMP-2) and Akt in cardiac supernatant and culture medium were assayed with ELISA methods.Results After co-culturing with FCS,beating myotubes were observed in 25.9 % BMSCs dishes after 1 to 2 weeks’ culture.The levels of TGF-β1 and BMP-2 in FCS concentrations were no more than that in young and adult cardiac supernatant.All BIO groups significantly enhanced the effects of FCS on differentiation of BMSCs into the cardiomyocyte-like cells (1 nM,83 %;10 nM,73 %;100 nM,100 %).Akt levels were higher in BMSCs cultural medium with FCS.Conclusions FCS could induce the differentiation of BMSCs into the cardiomyocyte-like cells.TGF-β1 and BMP-2 might not play a role in the differentiation of BMSCs induced by FCS.BIO enhanced the effects of FCS on the differentiation of BMSCs into cardiomyocyte-like cells,which might involve the Akt pathway.     

Safe time to warm ischemia and posttransplant survival of liver graft from non-heart-beating donors

AIM:To explore the dynamical changes of histology,histochemistry,energy metabolism,liver microcirculation,liver function and posttransplant survival of liver graft inrats under different warm ischemia times(WIT)and predictthe maximum limitation of liver graft to warm ischemia.METHODS:According to WIT,the rats were randomizedinto 7 groups,with WIT of 0,10,15,20,30,45,60 min,respectively.The recovery changes of above-mentioned indiceswere observed or measured after liver transplantation.Thegraft survival and postoperative complications in each subgroupwere analyzed.RESULTS:Liver graft injury was reversible and graduallyresumed normal structure and function after reperfusionwhen WIT was less than 30 min.In terms of graft survival,there was no significant difference between subgroupswithin 30 min WIT.When WIT was prolonged to 45 min,the recipients' long-term survival was severely insulted,and both function and histological structure of liver graftdeveloped irreversible damage when WIT was prolongedto 60 min.CONCLUSION:The present study indicates that rat livergraft can be safely subjected to warm ischemia within 30 min.The levels of ATP,energy charge,activities of glycogen,enzyme-histochemistry of liver graft and its recoverypotency after reperfusion may serve as the importantcriteria to evaluate the quality of liver graft.He XS,Ma Y,Wu LW,Ju WQ,Wu JL,Hu RD,Chen GH,Huang JF.Safe time to warm ischemia and posttransplantsurvival of liver graft from non-heart-beating donors.World JGastroenterol 2004;10(21):3157-3160http://www.wjgnet.com/1007-9327/10/3157.asp     

Phosphorylation of glycogen synthase kinase-3beta during preconditioning through a phosphatidylinositol-3-kinase--dependent pathway is cardioprotective

We previously reported that activation of phosphatidylinositol-3-kinase (PI3-kinase) is involved in ischemic preconditioning (PC). Our goal was to determine downstream targets of PI3-kinase. In perfused rat hearts, PC (4 cycles of 5 minutes of ischemia and 5 minutes of reflow) increased phosphorylation of glycogen synthase kinase-3beta (GSK-3beta), a downstream target of PI3-kinase and protein kinase B (PKB), an effect that was blocked by wortmannin. Because phosphorylation inactivates GSK-3beta, we examined whether PC-induced phosphorylation and inhibition of GSK-3beta is important in PC by using two inhibitors of GSK-3beta, lithium and SB 216763. Pretreatment of perfused rat hearts with lithium or SB 216763, before ischemia, mimicked the protective effects of PC; hearts treated with either lithium or SB 216763 had improved postischemic function and reduced infarct size. These findings indicate that inhibition of GSK-3beta is protective and that this PI3-kinase--dependent signaling pathway may play an important role in ischemic preconditioning.     

Inhibition of glycogen synthase kinase 3 beta ameliorates liver ischemia reperfusion injury by way of an interleukin-10-mediated immune regulatory mechanism

The ubiquitous serine/threonine kinase glycogen synthase kinase 3 beta (Gsk3β) differentially regulates macrophage Toll-like receptor (TLR)-triggered pro- and anti-inflammatory cytokine programs. This study was designed to determine the in vivo role and therapeutic potential of Gsk3β modulation in tissue inflammation and injury in a murine model of liver partial warm ischemia/reperfusion injury (IRI). As a constitutively activated liver kinase, Gsk3β became quickly inactivated (phosphorylated) following IR. The active Gsk3β, however, was essential for the development of IRI pathology, as administration of its specific inhibitor, SB216763, ameliorated the hepatocellular damage, evidenced by reduced serum alanine aminotransferase (sALT) levels and well-preserved liver architecture compared with controls. The liver protective effect of Gsk3β inhibition was dependent on an immune regulatory mechanism, rather than direct cytoprotection via mitochondria permeability transition pores (MPTP). Indeed: (1) coadministration of SB216763 and atractyloside (MPTP opener) failed to abrogate a local cytoprotective Gsk3β inhibition effect; (2) SB216763 selectively inhibited IR-triggered liver pro-inflammatory, but spared interleukin (IL)-10, gene induction programs; and (3) IL-10 neutralization restored liver inflammation and IRI in SB216763-treated mice. Gsk3β inactivation by IR was a self-regulatory mechanism in liver homeostasis, critically dependent on phosphoinositide 3 (PI3)-kinase activation, as administration of a PI3 kinase inhibitor, wortmannin, reduced Gsk3 phosphorylation and augmented liver damage. In vitro, IL-10 was critical for the suppression of pro-inflammatory gene programs by Gsk3 inhibition in bone marrow-derived macrophages in response to TLR4 stimulation. CONCLUSION: Our novel findings document the key immune regulatory function of Gsk3β signaling in the pathophysiology of liver IRI, and provide a rationale to target Gsk3β as a refined therapeutic strategy to ameliorate liver IRI.     

Bradykinin prevents reperfusion injury by targeting mitochondrial permeability transition pore through glycogen synthase kinase 3beta

Although bradykinin has been demonstrated to protect the heart at reperfusion, the detailed cellular and molecular mechanisms that mediate the protection remain elusive. Here we aimed to determine whether bradykinin protects the heart at reperfusion by modulating the mitochondrial permeability transition pore (mPTP) opening through glycogen synthase kinase 3beta (GSK-3beta). Bradykinin given at reperfusion reduced infarct size in isolated rat hearts subjected to 30 min regional ischemia followed by 2 h of reperfusion. The infarct-limiting effect of bradykinin was reversed by atractyloside, an opener of the mPTP, suggesting that bradykinin may protect the heart at reperfusion by modulating the mPTP opening. In support of this observation, bradykinin prevented the collapse of mitochondrial membrane potential (DeltaPsi(m)), an index of the mPTP opening. Bradykinin increased GSK-3beta phosphorylation at reperfusion, and the selective inhibitor of GSK-3beta SB216763 reduced infarct size and prevented the loss of DeltaPsi(m) by mimicking the effect of bradykinin. The effect of bradykinin on GSK-3beta phosphorylation was blocked by wortmannin and LY294002, and bradykinin increased Akt phosphorylation at reperfusion. Further experiments showed that the MEK inhibitor PD98059 prevented the effect of bradykinin on GSK-3beta. However, the mTOR/p70s6K pathway inhibitor rapamycin did not alter bradykinin-induced GSK-3beta phosphorylation and bradykinin failed to alter phosphorylation of either mTOR or p70s6K at reperfusion. Taken together, these data suggest that bradykinin protects the heart at reperfusion by modulating the mPTP opening through inhibition of GSK-3beta. The PI3-kinase/Akt pathway and ERK, but not the mTOR/p70s6K pathway account for the suppression of GSK-3beta by bradykinin.     

Effect of pressure overload on cardioprotection of mitochondrial KATP channels and GSK-3beta: interaction with the MPT pore

BACKGROUND: The mitochondrial permeability transition (MPT) pore may serve as the end-effector of cardioprotective mechanisms, namely the mitochondrial K(ATP) channels and glycogen synthase kinase-3beta (GSK-3beta). We recently showed that augmented MPT pore induction contributes to pressure overload-induced exacerbation of infarct size. This study tests the hypotheses that (i) elevation in perfusion pressure attenuates cardioprotection associated with activation of mitochondrial KATP channels or inhibition of GSK-3beta and (ii) perfusion pressure modulates the regulation of the MPT pore by mitochondrial KATP channels and/or GSK-3beta. METHODS: Langendorff-perfused hearts were subjected to a regional ischemia-reperfusion insult at a perfusion pressure of either 80 or 160 cm H2O. The perfusion medium contained no drug, diazoxide (80 micromol/l; mitochondrial KATP channel opener), lithium chloride (LiCl, 1 mmol/l; nonselective inhibitor of GSK-3beta), SB-216763 (3 micromol/l; selective inhibitor of GSK-3beta), cyclosporine A (0.2 micromol/l; inhibitor of MPT pore induction), glibenclamide (50 micromol/l; inhibitor of KATP channels), and the combination of cyclosporine A and glibenclamide or the combination of glibenclamide and LiCl. RESULTS: The increase in perfusion pressure in the absence of a drug caused larger infarcts, an effect associated with poorer recovery of function following ischemia reperfusion. Treatment with either diazoxide or cyclosporine A reduced infarct size at both perfusion pressures but in contrast to diazoxide, cyclosporine A was more protective at the higher pressure. On the other hand, LiCl and SB-216763 reduced infarct size at both pressures, with the effect more marked at the higher perfusion pressure. Glibenclamide did not affect infarct size but eliminated the cardioprotective effect of cyclosporine A while having no effect on LiCl-induced cardioprotection. CONCLUSION: Perfusion pressure primarily affects GSK-3beta-mediated regulation of MPT pore formation in the ischemic reperfused heart.     

Roles of phospho-GSK-3β in myocardial protection afforded by activation of the mitochondrial KATP channel

The aim of this study was to determine the roles of glycogen synthase kinase-3β (GSK-3β) in cardioprotection by activation of the mitochondrial ATP-sensitive K⁺ channel (mK_ATP channel). In isolated rat hearts, an mK_ATP activator, diazoxide, and a GSK-3β inhibitor, SB216763, similarly limited infarct size and the combination of these agents did not afford further protection. The protection by pre-ischemic treatment with diazoxide was abolished by inhibition of protein kinase C-ε (PKC-ε) or phosphatidylinositol-3-kinase (PI3K) upon reperfusion. Infusion of a GSK-3β inhibitor (LiCl), but not diazoxide, during reperfusion limited infarct size. Inhibition of PKC-ε or PI3K did not affect the protection by LiCl. Diazoxide infusion alone did not induce GSK-3β phosphorylation. However, diazoxide infusion before ischemia increased mitochondrial phospho-GSK-3β level and reduced cyclophilin-D (CypD) binding to adenine nucleotide translocase (ANT) at 10 min after reperfusion. This diazoxide-induced GSK-3β phosphorylation was inhibited by blockade of the mK_ATP channel before ischemia and by blockade of PKC-ε, PI3K or the adenosine A2b receptor at the time of reperfusion. Inhibition of GSK-3β by LiCl during reperfusion increased phospho-GSK-3β but had no significant effect on CypD-ANT binding. These results suggest that GSK-3β phosphorylation at the time of reperfusion by a PKC-ε, PI3K- and A2b receptor-dependent mechanism contributes to prevention of myocardial necrosis by pre-ischemic activation of the mK_ATP channel. Inhibition of CypD-ANT interaction may contribute to mK_ATP-induced myocardial protection, though it is not the sole mechanism of phospho-GSK-3β-mediated cytoprotection.     

缺血后处理减轻大鼠肥厚心肌缺血再灌注损伤的观察

目的探讨缺血后处理对心肌肥厚大鼠离体心脏缺血再灌注损伤的影响及其信号机制。方法通过腹主动脉结扎建立大鼠心肌肥厚模型,用Landendorff装置建立心肌肥厚大鼠离体心脏缺血再灌注模型。观察缺血后处理对心肌肥厚大鼠离体缺血再灌注心脏左心室收缩压,冠状动脉流量,肌酸磷酸激酶和乳酸脱氢酶释放,心肌梗死范围,心肌组织中蛋白激酶B／Akt（Akt）、糖原合成酶激酶-3β（GSK-3β）磷酸化的影响。结果与缺血再灌注对照组相比,缺血后处理组心脏左心室收缩压、冠状动脉流量显著高,冠状动脉循环流出液中肌酸磷酸激酶、乳酸脱氢酶含量低,心肌梗死范围减小,心肌组织中磷酸化Akt（Ser473）、磷酸化GSK-3β（Set9）水平高,磷脂酰肌醇-3激酶（PI3K）抑制剂渥曼青霉素（wortmannin）能够抑制缺血后处理所致的磷酸化Akt（Ser473）、磷酸化GSK-3β（Set9）水平升高,但只能部分消除缺血后处理的心脏保护效应。结论缺血后处理能够减轻心肌肥厚大鼠离体心脏缺血再灌注损伤,PI3K／Akt／GSK-3信号途径参与介导缺血后处理对离体缺血再灌注肥厚心肌的保护作用。     

糖原合成酶激酶-3β对巨噬细胞系RAW264.7活化的影响

目的探讨糖原合成酶激酶-3β（GSK-3β）对巨噬细胞系RAW264.7活化的影响。方法将生长状态良好的RAW264.7细胞分为3组：实验对照组、脂多糖（LPS）组和GSK-3β特异抑制剂SB216763干预组,在12 h、24 h进行指标检测。采用Western印迹法检测细胞GSK-3β、p-GSK-3β^ser9蛋白的表达,ELISA试剂盒法检测细胞上清IL-10、TNF-α的变化,RT-PCR检测细胞中5-LO mRNA变化,免疫荧光法检测ED1表达,电镜下观察RAW264.7细胞形态变化。结果12 h和24 h LPS组与对照组相比,p-GSK-3β^ser9表达减少,GSK-3β表达不变,活性升高;TNF-α、IL-10及5-LO mRNA表达增多（P〈0.05）;ED1表达绿色荧光明显增多;透射电镜观察LPS组巨噬细胞形态不规则,吞噬坏死物质细胞变多。12 h和24 h SB216763干预组与LPS组进行比较,p-GSK-3β^ser9表达明显增多,GSK-3β表达不变,活性降低;TNF-α及5-LO mRNA表达减少（P〈0.05）,IL-10表达明显增多（P〈0.05）;ED1绿色荧光表达减少;透射电镜观察细胞形态较规则。结论 GSK-3β对于RAW264.7细胞活化发挥重要的作用。     

Glycogen synthase kinase-3 inactivation is not required for ischemic preconditioning or postconditioning in the mouse

The inactivation of glycogen synthase kinase-3beta (GSK-3beta) is proposed as the event integrating protective pathways initiated by preconditioning and other interventions. The inactivation of GSK-3 is thought to decrease the probability of opening of the mitochondrial permeability transition pore. The aim of this study was to verify the role of GSK-3 using a targeted mouse line lacking the critical N-terminal serine within GSK-3beta (Ser9) and the highly homologous GSK-3alpha (Ser21), which when phosphorylated results in kinase inactivation. Postconditioning with 10 cycles of 5 seconds of reperfusion/5 seconds of ischemia and preconditioning with 6 cycles of 4 minutes of ischemia/6 minutes of reperfusion, similarly reduced infarction of the isolated perfused mouse heart in response to 30 minutes of global ischemia and 120 minutes of reperfusion. Preconditioning caused noticeable inactivating phosphorylation of GSK-3. However, both preconditioning and postconditioning still protected hearts of homozygous GSK-3 double knockin mice. Moreover, direct pharmacological inhibition of GSK-3 catalytic activity with structurally diverse inhibitors before or after ischemia failed to recapitulate conditioning protection. Nonetheless, cyclosporin A, a direct mitochondrial permeability transition pore inhibitor, reduced infarction in hearts from both wild-type and homozygous GSK-3 double knockin mice. Furthermore, in adult cardiac myocytes from GSK-3 double knockin mice, insulin exposure was still as effective as cyclosporin A in delaying mitochondrial permeability transition pore opening. Our results, which include a novel genetic approach, suggest that the inhibition of GSK-3 is unlikely to be the key determinant of cardioprotective signaling in either preconditioning or postconditioning in the mouse.     

磷脂酰肌醇3激酶信号通路在缺血后适应中对大鼠心肌保护机制的研究

目的研究缺血后适应(IPost)对大鼠心肌保护作用及磷脂酰肌醇3激酶(PI3K/Akt)信号通路机制。方法将32只雄性Wistar大鼠随机分为缺血再灌注组(A组),IPost组(B组),IPost+Wortmannin组(C组)和缺血再灌注+SB216763组(D组),每组8只。测定各组左心室收缩压(LVSP)和再灌注30 min冠状动脉流出液中乳酸脱氢酶和肌酸激酶含量。并测定心肌梗死面积,对心肌进行免疫组织化学染色,观察Akt磷酸化和GSK-3β磷酸化的表达。结果与B组比较,A组LVSP明显降低,乳酸脱氢酶和肌酸激酶含量明显升高(P0.05);同时IPost干预减小了心肌梗死面积(47.3% vs 29.5%),B组Akt磷酸化和GSK-3β磷酸化表达增加。结论 IPost对体外大鼠缺血再灌注损伤有明确的保护作用。Wortmannin可削弱IPost的保护作用,SB216763具有模拟IPost的心肌保护作用,Akt和GSK-3β的磷酸化水平在IPost的心肌保护作用信号通道传导机制中具有重要地位。