The cyclic adenosine 3′,5′ monophosphate-dependent protein kinase system in breast cancer

Components of the cyclic adenosine 3′,5′ monophosphate (AMP) dependent protein kinase sys- tem have been measured in primary tumours from 55 patients with invasive breast cancer. There were highly significant positive correlations between levels of regulatory subunits as measured by cyclic AMP binding proteins and catalytic kinase activity (both basal and cyclic AMP-activated). This suggests that, in general, increased expression of binding proteins is accompanied by a corresponding elevated level of catalytic activity. Nevertheless, individual tumours could have substantially different proportions of regulatory and catalytic activities. Whether such differences influence tumour behaviour remains to be determined.     

Activation of cyclic adenosine monophosphate-dependent protein kinase a signaling prevents liver ischemia/reperfusion injury in mice

Hepatic ischemia/reperfusion injury (IRI) occurs in multiple clinical settings, including liver transplantation. The cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) pathway inhibits hepatocellular apoptosis and regulates toll-like receptor 4-triggered inflammation responses in vitro. Here we examined the function and therapeutic potential of cAMP-PKA activation in a murine (C57/BL6) model of liver warm ischemia (90 minutes) followed by reperfusion. Liver IRI triggered cAMP-PKA activation, whereas the administration of its specific inhibitor, H89, exacerbated hepatocellular damage. Conversely, forskolin therapy, which activates PKA by elevating cAMP levels, protected livers from IRI; this was evidenced by diminished serum alanine aminotransferase levels and well-preserved tissue architecture. Liver protection due to cAMP-PKA stimulation was accompanied by diminished neutrophil and macrophage infiltration/activation, reduced hepatocyte necrosis/apoptosis, and increased cAMP response element-binding protein (CREB) expression and augmented interleukin-10 (IL-10) expression. The neutralization of IL-10 restored liver damage in otherwise ischemia/reperfusion-resistant, forskolin-treated mice. In vitro, cAMP-PKA activation diminished macrophage tumor necrosis factor α, IL-6, and IL-12 in an IL-10-dependent manner and prevented necrosis/apoptosis in primary mouse hepatocyte cultures. Our novel findings in a mouse model of liver IRI document the importance of cAMP-PKA signaling in hepatic homeostasis and cytoprotection in vivo. The activation of cAMP-PKA signaling differentially regulates local inflammation and prevents hepatocyte death, and this provides a rationale for novel therapeutic approaches to combating liver IRI in transplant recipients.     

蛋白激酶C-环磷酸腺苷信号通路在三氧化二砷诱导膀胱癌凋亡中的作用

目的探讨三氧化二砷(As_2O_3)诱导膀胱癌凋亡过程中蛋白激酶C(PKC)和环磷酸腺苷(cAMP)水平的改变及其在膀胱癌凋亡中的作用。方法应用原位末端转移酶标记技术(TUNEL)、放射免疫、酶联免疫、免疫组化和Western blot等方法分别检测As_2O_3作用后膀胱癌T24细胞凋亡、凋亡过程中PKC和cAMP改变、caspase 3蛋白表达及caspase 3激活。结果药物作用24 h后,凋亡细胞呈现棕黄色浓染和绿色荧光。对照组细胞凋亡率0.86%,PKC总量2.55pmol·min~(-1)·μg~(-1),cAMP含量22.56pmol/ml,caspase 3蛋白表达率8.01%。与对照组相比,5μmol/L和10μmol/L As_2O_3组细胞凋亡率分别升高8.51倍和13.33倍,PKC总量分别降低59.22%和64.71%,cAMP含量分别升高5.34倍和4.23倍,caspase 3蛋白表达率分别上调3.96倍和6.76倍,差异有统计学意义(P＜0.05)。与As_2O_3组相比,5μmol/L和10μmol/L As_2O_3+100nmol/L PKC激动剂佛波酯(PMA)组细胞凋亡率分别降低40.22%和45.58%,PKC总量分别升高1.00倍和0.76倍,cAMP含量分别降低8.37%和31.46%,caspase 3蛋白表达率分别下调51.09%和65.03%。As_2O_3组均可显著激活caspase 3活性,As_2O_3+100nmol/L PMA组对caspase 3激活明显弱于同浓度As_2O_3组。结论As_2O_3可通过降低PKC和升高cAMP水平启动膀胱癌T24细胞凋亡,诱导细胞凋亡。     

Involvement of cyclic adenosine monophosphate-dependent protein kinase A and pertussis toxin-sensitive G proteins in the migratory response of human CD14+ mononuclear cells to katacalcin.

Katacalcin (KC) belongs to a small family of polypeptides that are encoded by the calc-1 gene and also include calcitonin (CT) and procalcitonin NH2-terminal cleavage peptide (N-ProCT). Biological roles of KC or N-ProCT are unknown. To determine whether these polypeptides affect leukocyte function, forearm venous blood polymorphonuclear neutrophils and CD14+ peripheral blood mononuclear cells (PBMCs) were isolated from healthy human donors. Cell migration was assessed in a blindwell chemotaxis chamber using nitrocellulose micropore filters. Cellular levels of cyclic adenosine monophosphate (cAMP) were measured by HPLC; activation of protein kinase A was studied by Western blot. Fluorochrome-labeled peptide binding to cells was studied by fluorescence-activated cell sorting (FACS) and intracellular calcium transients were studied by confocal microscopy with FLUO-3. KC elicited concentration-dependent migration of CD14+ PBMC at concentrations from the atomolar to the micromolar range and deactivated attractant-induced chemotaxis. CT N-terminal flanking peptide had no such effect. Neutrophils did not migrate toward any of those peptides and their oxygen-free radical release was not affected as measured fluorometrically. Functional responses of CD14+ PBMC to KC correlated to forskolin-sensitive cAMP accumulation in cells and were inhibited by protein kinase A inhibitor (PKI) and Rp diastereomer of adenosine 3',5'-cyclic monophosphorothioate. Treatment of CD14+ PBMC with KC activated protein kinase A(C alpha). Intracellular calcium was decreased with CT, KC, and procalcitonin (PCT). Binding studies showed that KC might share the binding site with CT and PCT. Data indicate that KC regulates human CD14+ PBMC migration via signaling events involving protein kinase A-dependent cAMP pathways.     

丝裂原蛋白激酶信号转导通路在机械通气相关性肺损伤中的作用

目的观察机械通气介导肺损伤（VILI）过程中丝裂原蛋白激酶（MAPK）的活性变化以及对细胞因子的影响，从中探讨VILI发生机制和MAPK的作用。方法72只SD大鼠随机分为未处理的对照组（不行机械通气）、正常通气组、过度通气组和采用MAPK抑制剂SP600125（JNK）、SB203580（p38）、PD98059（ERK）分别预处理上述3组。机械通气4h后取大鼠肺组织采用Western blot方法测定各组的总JNK、ERK、p-38蛋白激酶的表达及其磷酸化水平变化。同时以酶联免疫吸附试验（EUSA）方法测定大鼠肺组织、支气管肺泡灌洗液（BALF）和血浆中的肿瘤坏死因子-α（TNF-α）、巨噬细胞炎性蛋白-2（MIP-2）浓度。结果正常和过度机械通气4h后均能激活JNK、ERK、p38激酶，但以过度通气组为著（P〈0．01）。过度通气组大鼠肺组织、BALF、血浆中的TNF-α、MIP-2含量显著高于其他组（P〈0．01）。JNK、ERK、p38抑制剂显著降低肺组织、BALF中的TNF-α、MIP-2含量（P〈0．05或0．01），且JNK和ERK抑制剂作用强于p38抑制剂。结论过度机械通气激活了肺细胞中的JNK、ERK、p38激酶，且JNK、ERK、p38参与了VILI细胞因子的产生，即MAPK信号转导通路的激活可能是VILI发生机制之一。     

环磷酸腺苷/蛋白激酶A信号转导通路在重症急性胰腺炎肺损伤中的作用

目的 探讨环磷酸腺苷/蛋白激酶A(cAMP/PKA)信号转导通路在重症急性胰腺炎肺损伤的作用机制.方法 健康雄性SD大鼠72只,按完全随机法分为假手术(SO)组、重症急性胰腺炎组(SAP组)、SAP+ H89(cAMP抑制剂)组,后两组按取材时间不同又分为3、6、12及24 h四个亚组,共9组,每组8只.采用酶联免疫吸附法检测血清TNF-α、IL-1β,同时观察胰腺和肺组织的病理变化,免疫组织化学蛋白方法检测cAMP依赖PKA催化亚基C(PKA C)和磷酸化的血管扩张刺激磷蛋白(p-VASP),荧光定量聚合酶链反应检测肺组织VSAP mRNA表达水平.结果 与SO组比较,SAP组各时间点血清TNF-α 、IL-1β明显上升(P＜0.05),胰腺、肺病理学改变明显,肺组织PKA C蛋白、VASP磷酸化水平及VASPmRNA表达水平明显增强(P＜0.05),12 h达高峰[TNF-α(266.07±17.14) pg/mL、IL-1β (169.17±25.92) pg/mL、PKA C(210.69 ±6.32)×103、p-VASP(56.62 ±0.57)×103、VASPmRNA(2.06 ±0.21)],且与TNF-α、IL-1β之间存在明显的正相关性.与SAP组比较,SAP+ H89组各时间点胰腺、肺病理学改变明显减轻,肺组织PKA C蛋白、VASP磷酸化水平及VSAP mRNA表达水平明显下降(P＜0.05).结论 cAMP/PKA信号转导通路的活化参与了重症急性胰腺炎肺损伤的病理过程,可能与TNF-α及IL-1β水平上调及VASP磷酸化而发挥作用有关.     

Smooth muscle contractility in prostatic hyperplasia: Role of cyclic adenosine monophosphate

The role of cyclic 3′-5′ adenosine monophosphate (cAMP) on α₁-adreno-ceptor (α₁-receptor) induced smooth muscle contractions in symptomatic benign prostatic hyperplasia (BPH) was investigated. Application of the selective α₁-receptor agonist phenylephrine (PE) induced fully reversible contractions in a dose-dependent fashion. Phosphodiesterase (PDE) inhibitors blocking the degradation of cAMP suppressed the PE induced contractions as follows: theophylline (1 mM), 91.1 ± 1.4%; papaverine (0.5 mM), 822.8 ± 3.2%; milrinone (0.5 mM), 68.2 ± 0.6%. Forskolin (50 μM), which elevates cAMP through direct activation of adenylatecyclase (AC), inhibited the PE induced contractions by 82.4 ± 3.6%. To further increase the intracellular cAMP concentration ([cAMP]_i), the membrane permeable cAMP analogue N⁶-2′-O-dibutyryladenosine derivative (dBcAMP; 1 mM) was applied and reduced the PE evoked contractions by 69.8 ± 2.3%. We conclude that elevation of [cAMP]_i is an important step in inducing smooth muscle relaxation. © 1994 Wiley-Liss, Inc.     

Effects of plant extract neferine on cyclic adenosine monophosphate and cyclic guanosine monophosphate levels in rabbit corpus cavernosum in vitro

Aim： To further investigate the relaxation mechanism of neferine （NED, a bis-benzylisoquinoline alkaloid extracted （isolated） from the green seed embryo of Nelumbo nucifera Gaertn in China, on rabbit corpus cavernosum tissue in vitro. Methods： The effects of Nef on the concentrations of cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） in isolated and incubated rabbit corpus cavernosum tissue were recorded using ^125I radioimmunoassay. Results： The basal concentration of cAMP in corpus cavernosum tissue was 5.67 ± 0.97 pmol/mg. Nef increased the cAMP concentration in a dose-dependent manner （P 〈 0.05）, but this effect was not inhibited by an adenylate cyclase inhibitor （cis-N-[2-phenylcyclopentyl]azacyclotridec-1-en-2-amine, MDL-12, 330A） （P 〉 0.05）. The accumulation of cAMP induced by prostaglandin Et （PGEt, a stimulator of cAMP production） was also augmented by Nef in a dose-dependent manner （P 〈 0.05）. The basal concentration of cGMP in corpus cavernosum tissue is 0.44 ± 0.09 pmol/mg. Nef did not affect this concentration of cGMP, either in the presence or in the absence of a guanyl cyclase inhibitor （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ） （P 〉 0.05）. Also, sodium nitroprusside （SNP, a stimulator of cGMP production）-induced cGMP production was not enhanced by Nef （P 〉 0.05）. Conclusion： Nef, with its relaxation mechanism, can enhance the concentration of cAMP in rabbit corpus cavernosum tissue, probably by inhibiting phosphodiesterase activity. （Asian JAndro12008 Mar; 10： 307-312）     

Extracellular signal-related kinase 1/2 and p38 mitogen-activated protein kinase pathways serve opposite roles in neutrophil cytotoxicity.

BACKGROUND: Inflammatory stimuli rapidly activate mitogen-activated protein kinases (MAPKs) in neutrophils (PMNs). However, their role in cytotoxic function remains unknown. Elucidating the signals involved in release of cytotoxic agents from PMNs may provide new avenues for therapy in diseases of diminished or excessive PMN function. HYPOTHESIS: The p38 MAPK and extracellular signal-related kinase 1/2 (ERK1/2) modulate superoxide generation and elastase release in activated human PMNs. STUDY DESIGN: Isolated human PMNs were incubated with specific inhibitors of MAPK pathways, or vehicle control solution, before activation with the bacterial peptide f-Met-Leu-Phe. MAIN OUTCOME MEASURES: The rate of superoxide release from activated PMNs was measured by the superoxide dismutase-inhibitable reduction of cytochrome-c. Elastase release from PMNs was determined by cleavage of the substrate Ala-Ala-Pro-Val-pNA. RESULTS: Superoxide release from activated PMNs was inhibited by blockade of p38 MAPK activation but unaffected by blockade of ERK1/2. Conversely, elastase release was unaffected by p38 MAPK inhibition and increased by ERK1/2 inhibition. CONCLUSIONS: Activation of p38 MAPK promotes superoxide release from PMNs activated by f-Met-Leu-Phe. The ERK1/2 pathway may serve as a negative feedback mechanism for granule exocytosis.     

Endothelin-1 decreases microvascular fluid leak via second messenger cyclic nucleotides and protein kinase a signal transduction

Introduction. Endothelin-1 (ET-1) decreases microvascular fluid leak by an unknown mechanism. Elevated cAMP levels, depressed cGMP levels, and protein kinase A (PKA) activation are all known to decrease fluid leak. We hypothesized that ET-1 decreases permeability by increased cAMP levels, decreased cGMP levels, and PKA activation. The purpose of this series of experiments was to determine ET-1’s effect on venular fluid leak during (1) cAMP synthesis inhibition, (2) increased cGMP levels, and (3) PKA activation inhibition. Methods. Using the modified-Landis technique, rat mesenteric venules were cannulated to measure hydraulic permeability, L_p (units × 10⁻⁷ cm/s/cmH₂O). L_p was measured during continuous perfusion of ET-1 and a test solution. The test solutions consisted of (1) a cAMP synthesis inhibitor (2′,5′ddA), (2) an inhibitor of cGMP degradation (zaprinast), or (3) an inhibitor of PKA (H-89). These results were compared to L_p measurements from the different test solutions alone. Data were statistically analyzed using unpaired t-tests. L_p values are represented as mean ± standard error. Results. ET-1 did not change L_p during (1) cAMP synthesis inhibition and (2) PKA inhibition: cAMP inhibitor with and without ET-1 (L_p = 3.6 ± 0.1 versus 3.6 ± 0.2, P = 0.4, n = 4) and PKA inhibitor with and without ET-1 (L_p = 2.3 ± 0.2 versus 2.6 ± 0.2, P = 0.3, n = 5). Increased cGMP levels (inhibition of cGMP degradation) failed to block the permeability-decreasing effect of ET-1. Compared to increased levels of cGMP alone, ET-1 in the presence of increased cGMP levels decreased L_p from 2.3 ± 0.2 to 1.5 ± 0.1 (P < 0.008, n = 6). Conclusion. The permeability-decreasing effect of ET-1 was blocked by cAMP and PKA inhibition. In contrast, ET-1 was able to decrease fluid leak while cGMP degradation was inhibited. The intracellular mechanism of ET-1 may involve increased cAMP production and PKA activation, but not cGMP degradation. Further understanding of intracellular mechanisms that control microvascular fluid leak may lead to the development of a pharmacologic therapy to control third space fluid loss in severely injured or septic patients.     

Inhibition of heme oxygenase-1 in microvascular lung pericytes diminishes at high concentrations of an inflammatory mediator

Post-traumatic inflammation and sepsis induce changes in the lung microvasculature causing increased permeability. Pericytes, contractile cells positioned abluminally to endothelial cells, play a role in regulating this response. An in vitro model of microvascular lung pericytes (MLP) was used to investigate the effect of inhibiting heme oxygenase-1 (HO-1), a stress-induced enzyme, in the presence of varying levels of lipopolysaccharide (LPS), a mediator in the initiation of inflammation, on pericyte contractility. Rat MLP were cultured on collagen gel matrices. Cells were exposed to three concentrations of LPS in the presence of zinc protoporphyrin IX (ZnPP-9), a known inhibitor of HO-1. After 24 hours, the surface area of the collagen disks was quantified, thereby measuring pericyte contraction. ZnPP-9 caused a significant attenuation of the LPS-induced relaxation of the pericytes (P < or = 0.003). The effects of ZnPP-9, however, depended on the concentration of LPS to which the pericytes were exposed. Greater concentrations of LPS decrease the attenuating power of ZnPP-9. The inhibition of HO-1 diminished MLP relaxation triggered by LPS. The effect of ZnPP-9, however, is dependent on the concentration of LPS to which the MLP are exposed, indicating its saturation. ZnPP-9 may antagonize the microvascular response to trauma.     

环腺苷酸效应元件结合蛋白在学习记忆中的作用及机制

背景 环腺苷酸效应元件结合蛋白(cAMP response-element binding protein,CREB)是新发现的学习记忆正调控因子.近年来的研究提示CREB可能通过多种途径调控学习记忆. 目的 阐述CREB在学习记忆中的作用及机制,为认知障碍相关疾病的防治提供思路. 内容 阐述CREB的来源、结构及其在学习记忆中的作用.分析其调控学习记忆的相关机制. 趋向 CREB的确切上游调控机制及自身的表达调控需要进一步明确,对其深入研究可为多种认知障碍疾病的防治提供新的靶点与思路.     

Characterization of endothelin receptors and effects of endothelin on diacylglycerol and protein kinase C in retinal capillary pericytes

Retinal capillary pericyte is a cell type selectively lost in early diabetic retinopathy. The physiological function of pericytes is not yet clearly identified, although it probably has contractile properties. We determined the specific binding of endothelin 1, a 21-amino acid peptide with potent vasoconstrictive action, and the stimulation of diacylglycerol/protein kinase C (DAG/PKC) pathway in cultured retinal capillary pericytes by endothelin. A single specific binding site for 125I-labeled endothelin was identified, with an apparent Kd of 1.3 nM and a maximal binding capacity of approximately 1-2 x 10(5) sites/cell. Endothelin (100 nM) increased total cellular DAG content by 15% at 5 min and 24% at 10 min. When pericytes were labeled isotopically with [3H]glycerol, endothelin stimulated [3H]DAG formation by 100% at 10 min and 88% at 30 min. After 10 min of endothelin treatment, PKC activities were increased by 60 and 100% in the membranous and cytosolic pools, respectively. We conclude that bovine retinal capillary pericytes possess numerous high-affinity specific binding sites for endothelin that mediate the action of endothelin by the stimulation of the DAG/PKC pathway in pericytes. These findings suggest that endothelin is a regulator of the contractile properties of pericytes, which may be adversely affected in diabetic retinopathy.     

蛋白激酶C和线粒体ATP敏感性钾通道在未成熟心肌预处理中的作用

目的探讨蛋白激酶C(PKC)和线粒体三磷酸腺苷敏感性钾通道(mitoKATP)在未成熟心肌预处理保护中的作用。方法采用Langendorff离体心脏灌注模型,30只新生日本长耳大白兔分为5组:缺血/再灌注组(I/R组),心脏缺血预处理组(E1组),蛋白激酶C(PKC)阻滞剂chelerythrine(CLT) 心脏缺血预处理(E2组),mitoKATP阻滞剂5-hydroxydecanoate(5-HD) 心脏缺血预处理(E3组),mitoKATP通道开放剂Diazoxide(Diaz)预处理组(E4组)。以血流动力学、生化指标、心肌超微结构等作为观察指标。结果E1和E4组心功能恢复、心肌含水量优于I/R、E2和E4组(P<0.05),三磷酸腺苷含量、超氧化物歧化酶活性、心肌线粒体Ca2 -ATPase活性、心肌线粒体合成三磷酸腺苷(ATP)的能力优于I/R、E2和E4组(P<0.01),丙二醛含量、血清肌酸激酶和乳酸脱氢酶漏出率、心肌细胞内Ca2 含量、心肌线粒体Ca2 含量低于I/R、E2和E4组(P< 0.01),心肌超微结构损伤较I/R、E2和E4组明显减轻。结论心肌缺血预处理对未成熟心肌具有明显的保护作用,其机制可能是通过PKC的激活和mitoKATP通道的开放起作用。     

阻塞性黄疸大鼠肝细胞凋亡及蛋白激酶C信号通道的调控作用

目的探讨阻塞性黄疸肝损害的调控机制。方法采用胶原酶原位肝灌注法获取大鼠肝细胞，行原代培养，用蛋白激酶(PK)C激动剂帕斯酶埃(PMA)、拮抗剂切勒斯埃作用于肝细胞，再用50μmol／L甘氨鹅脱氧胆酸钠(GCDC)作用后行流式细胞术(FCM)及用末端脱氧核苷酸转移酶(TdT)介导的脱氧核苷酸(duTP)缺口末端标记技术(TUNEL)检测肝细胞凋亡情况。结扎大鼠胆总管后3、7、14、21d处死大鼠，用TUNEL技术及免疫组织化学方法检测阻塞性黄疸大鼠肝脏组织细胞凋亡状态及PKC蛋白的表达。结果随PMA浓度的增加，肝细胞的凋亡明显增加。随Chelerythrine的增加，肝细胞的凋亡明显减少。大鼠胆总管结扎后随结扎时间的延长细胞凋亡指数(AI)增加，结扎14d后AI达高峰。PKC表达越强，AI就越高。结论PKC信号通道参与了阻塞性黄疸肝细胞凋亡的调节，并在阻塞性黄疸肝损害的发生和发展中起重要作用。     

Angiotensin II suppresses adenosine monophosphate-activated protein kinase of podocytes via angiotensin II type 1 receptor and mitogen-activated protein kinase signaling

Background

Adenosine monophosphate (AMP)-activated protein kinase (AMPK), as a sensor of cellular energy status, has been known to play an important role in the pathophysiology of diabetes and its complications. As AMPK is also expressed in podocytes, it is possible that podocyte AMPK would be an important contributing factor in the development of diabetic proteinuria. We investigated the roles of AMPK in the pathological changes of podocytes induced by angiotensin II (Ang II), a major injury inducer in diabetic proteinuria.

Methods

Mouse podocytes were incubated in media containing various concentrations of Ang II and AMPK-modulating agents. The changes of AMPKα were analyzed by confocal imaging and Western blotting in response to Ang II.

Results

Ang II changed the localization of AMPKα from peripheral cytoplasm into internal cytoplasm and peri- and intranuclear areas in podocytes. Ang II also reduced AMPKα (Thr172) phosphorylation in time- and dose-sensitive manners. In particular, 10^?7 M Ang II reduced phospho-AMPKα significantly and continuously at 6, 24, and 48 h. AMPK activators, metformin and 5-aminoimidazole-4-carboxamide-1β-riboside, restored the suppressed AMPKα (Thr172) phosphorylation. Losartan, an Ang II type 1 receptor antagonist, also recovered the suppression and the mal-localization of AMPKα, which were induced by Ang II. PD98059, a mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitor, also restored the AMPKα (Thr172) phosphorylation suppressed by Ang II.

Conclusion

We suggest that Ang II induces the relocation and suppression of podocyte AMPKα via Ang II type 1 receptor and MAPK signaling pathway, which would be an important mechanism in Ang II-induced podocyte injury.     

环磷酸腺苷-蛋白激酶A信号通路对大鼠深低温缺血再灌注后肺组织水通道蛋白-5的调控及其与肺损伤的关系

目的 探讨环磷酸腺苷-蛋白激酶A (cAMP-PKA)信号通路对大鼠深低温缺血再灌注后肺组织水通道蛋白-5(AQP5)的调控及其与肺损伤的关系.方法 将28只Wistar大鼠随机分为假手术组(sham组)、深低温缺血再灌注损伤组(I/R组)、H89组和forskolin组,每组7只.I/R组大鼠体表降温至深低温后阻断左下肺门30 min后开放、复温;sham组只开胸但不降温阻断左下肺门;H89组和forskolin组分别于实验前2d腹腔注射H89和forskolin,其余操作同I/R组;测量左下肺组织湿重/干重比值(W/D比值)同时观察组织学变化,实时定量聚合酶链反应(Real-time PCR)以及Westem blot法检测左下肺组织中AQP5 mRNA和蛋白表达.结果 I/R组与sham组比较,肺组织AQP5 mRNA表达减少(0.67±0.15,P＜0.01)、AQP5蛋白表达减少(0.47±0.09,P＜0.01),W/D比值增高(5.27±0.92,P＜0.01),肺组织形态及结构明显受损;forskolin干预组与I/R组比较,肺组织AQP5 mRNA表达增加(0.83 ±0.30,P＜0.01)、AQP5蛋白表达增加(0.89±0.07,P＜0.01)、W/D比值减低(3.98±0.45,P＜0.01),肺组织病理形态学改变轻于I/R组,与sham组比较,AQP5表达减少,但差异无统计学意义;H89干预组与I/R组和sham组比较,肺组织AQP5 mRNA表达减少(0.53±0.11,P＜0.01)、AQP5蛋白表达减少(0.31±0.03,P＜0.01),W/D比值增高(6.13 ±0.78,P＜0.01),肺组织形态及结构受损最为明显.结论 深低温缺血再灌注肺组织中AQP5表达下调且与肺损伤程度相关,cAMP-PKA信号通路可能参与AQP5的调控.     

Superior protection in orthotopic rat lung transplantation with cyclic adenosine monophosphate and nitroglycerin-containing preservation solution.

BACKGROUND: Primary lung graft failure is common, and current lung preservation strategies are suboptimal. Because the decline in lung levels of cyclic adenosine monophosphate and cyclic guanosine monophosphate during preservation could enhance adhesiveness of endothelial cells for leukocytes as well as increase vascular permeability and vasoconstriction, we hypothesized that buttressing these levels by means of a preservation solution would significantly improve lung preservation. METHODS: An orthotopic rat left lung transplantation model was used. Lungs were harvested from male Lewis rats and preserved for 6 hours at 4 degrees C with (1) Euro-Collins solution (n = 8); (2) University of Wisconsin solution (n = 8); (3) low-potassium dextran glucose solution (n = 8); (4) Columbia University solution (n = 8), which contains a cyclic adenosine monophosphate analog (dibutyryl cyclic adenosine monophosphate) and a nitric oxide donor (nitroglycerin) to buttress cyclic guanosine monophosphate levels; or (5) Columbia University solution without cyclic adenosine monophosphate or nitroglycerin (n = 8). PaO2, pulmonary vascular resistance, and recipient survival were evaluated 30 minutes after left lung transplantation and removal of the nontransplanted right lung from the pulmonary circulation. RESULTS: Among all groups studied, grafts stored with Columbia University solution demonstrated the highest Pa O2 (355 +/- 25 mm Hg for Columbia University solution versus 95 +/- 22 mm Hg for Euro-Collins solution, P <.01, 172 +/- 55 mm Hg for University of Wisconsin solution, P <.05, 76 +/- 15 mm Hg for low-potassium dextran glucose solution, P <.01, and 82 +/- 25 mm Hg for Columbia University solution without cyclic adenosine monophosphate or nitroglycerin, P <.01) and the lowest pulmonary vascular resistances (1 +/- 0.2 mm Hg * mL-1 * min-1 for Columbia University solution versus 12 +/- 4 mm Hg * mL-1 * min-1 for Euro-Collins solution, P <.01, 9 +/- 2 mm Hg * mL-1 * min-1 for University of Wisconsin solution, 14 +/- 6 mm Hg * mL-1 * min-1 for low-potassium dextran glucose solution, P <.01, and 8 +/- 2 mm Hg * mL-1 * min-1 for Columbia University solution without cyclic adenosine monophosphate and nitroglycerin). These functional and hemodynamic improvements provided by Columbia University solution were accompanied by decreased graft leukostasis and decreased recipient tumor necrosis factor alpha and interleukin 1alpha levels compared with the other groups. In toto, these improvements translated into superior survival among recipients of Columbia University solution-preserved grafts (100% for Columbia University solution, 37% for Euro-Collins solution, P <.01, 50% for University of Wisconsin solution, P <.05, 50% for low-potassium dextran glucose solution, P <.05, and 13% for Columbia University solution without cyclic adenosine monophosphate and nitroglycerin, P <.01). CONCLUSION: Nitroglycerin and cyclic adenosine monophosphate confer beneficial vascular effects that make Columbia University solution a superior lung preservation solution in a stringent rat lung transplantation model.