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1.
Cells ; 12(17)2023 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-37681864

RESUMO

Stroke is a major global health problem that causes significant mortality and long-term disability. Post-stroke neurological impairment is a complication that is often underestimated with the risk of persistent neurological deficits. Although traditional Chinese medicines have a long history of being used for stroke, their scientific efficacy remains unclear. Scutellaria baicalensis, an herbal component known for its anti-inflammatory and antioxidant properties, has traditionally been used to treat brain disorders. This study investigated the therapeutic effects of the Scutellaria baicalensis extraction (SB) during the acute stage of ischemic stroke using photothrombotic (PTB)-induced and transient middle cerebral artery occlusion (tMCAO) model mice. We found that SB mitigated ischemic brain injury, as evidenced by a significant reduction in the modified neurological severity score in the acute stage of PTB and both the acute and chronic stages of tMCAO. Furthermore, we elucidated the regulatory role of SB in the necroptosis and pyroptosis pathways during the acute stage of stroke, underscoring its protective effects. Behavioral assessments demonstrated the effectiveness of SB in ameliorating motor dysfunction and cognitive impairment compared to the group receiving the vehicle. Our findings highlight the potential of SB as a promising therapeutic candidate for stroke. SB was found to help modulate the programmed cell death pathways, promote neuroprotection, and facilitate functional recovery.


Assuntos
AVC Isquêmico , Acidente Vascular Cerebral , Animais , Camundongos , AVC Isquêmico/tratamento farmacológico , Scutellaria baicalensis , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/tratamento farmacológico , Apoptose , Piroptose
2.
J Breast Cancer ; 24(5): 463-473, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34652077

RESUMO

Immunoreactive dynamics of tumor-infiltrating lymphocytes (TILs) within the tumor microenvironment in breast cancer are not well understood. This study aimed to investigate the spatiotemporal cellular dynamics of TILs in breast cancer models. Breast cancer cells were implanted into the dorsal skinfold chamber of BALB/c nude mice, and T lymphocytes were adoptively transferred. Longitudinal intravital imaging was performed, and the spatiotemporal dynamics of TILs were assessed. In the 4T1 model, TILs progressively exhibited increased motility, and their motility inside the tumor was significantly higher than that outside the tumor. In the MDA-MB-231 model, the motility of TILs progressively decreased after an initial increase. TIL motility in the MDA-MB-231 and MCF-7 models differed significantly, suggesting an association between programmed death-ligand 1 expression levels and TIL motility, which warrants further investigation. Furthermore, intravital imaging of TILs can be a useful method for addressing dynamic interactions between TILs and breast cancer cells.

3.
Theranostics ; 11(1): 79-92, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33391462

RESUMO

Transarterial chemoembolization (TACE) is an image-guided locoregional therapy used for the treatment of patients with primary or secondary liver cancer. However, conventional TACE formulations are rapidly dissociated due to the instability of the emulsion, resulting in insufficient local drug concentrations in the target tumor. Methods: To overcome these limitations, a doxorubicin-loaded albumin nanoparticle-conjugated microbubble complex in an iodized oil emulsion (DOX-NPs-MB complex in Lipiodol) has been developed as a new ultrasound-triggered TACE formulation. Results: (1) Microbubbles enhanced therapeutic efficacy by effectively delivering doxorubicin- loaded nanoparticles into liver tumors via sonoporation under ultrasound irradiation (US+). (2) Microbubbles constituting the complex retained their function as an ultrasound contrast agent in Lipiodol. In a rabbit VX2 liver cancer model, the in vivo study of DOX-NPs-MB complex in Lipiodol (US+) decreased the viability of tumor more than the conventional TACE formulation, and in particular, effectively killed cancer cells in the tumor periphery. Conclusion: Incorporation of doxorubicin-loaded microbubble in the TACE formulation facilitated drug delivery to the tumor with real-time monitoring and enhanced the therapeutic efficacy of TACE. Thus, the enhanced TACE formulation may represent a new treatment strategy against liver cancer.


Assuntos
Albuminas , Antibióticos Antineoplásicos/administração & dosagem , Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica/métodos , Doxorrubicina/administração & dosagem , Neoplasias Hepáticas/terapia , Microbolhas , Nanopartículas , Animais , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/patologia , Modelos Animais de Doenças , Composição de Medicamentos , Sistemas de Liberação de Medicamentos , Óleo Etiodado , Infusões Intra-Arteriais , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Imageamento por Ressonância Magnética , Masculino , Coelhos , Ultrassonografia
4.
Biomed Opt Express ; 10(6): 2719-2729, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31259046

RESUMO

In vivo, longitudinal observation of tumorigenesis in a live mouse model over an extended time period has been actively pursued to obtain a better understanding of the cellular and molecular mechanism in a highly complex tumor microenvironment. However, common intravital imaging approaches based on a conventional laser scanning confocal or a two-photon microscope have been mostly limited to the observation of superficial parts of the solid tumor tissue. In this work, we implemented a small diameter needle-shaped side-view confocal endomicroscope that can be directly inserted into a solid tumor in a minimally-invasive manner in vivo. By inserting the side-view endomicroscope into the breast tumor from the surface, we achieved in vivo depth-wise cellular-level visualization of microvasculature and fluorescently labeled tumor cells located deeply inside the tumor. In addition, we successfully performed longitudinal depth-wise visualization of a growing breast tumor over three weeks in a live mouse model, which revealed dynamic changes in microvasculature such as a decreasing amount of intratumoral blood vessels over time.

5.
Eur Respir J ; 53(3)2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30635296

RESUMO

The lung is highly vulnerable during sepsis, yet its functional deterioration accompanied by disturbances in the pulmonary microcirculation is poorly understood. This study aimed to investigate how the pulmonary microcirculation is distorted in sepsis-induced acute lung injury (ALI) and reveal the underlying cellular pathophysiologic mechanism.Using a custom-made intravital lung microscopic imaging system in a murine model of sepsis-induced ALI, we achieved direct real-time visualisation of the pulmonary microcirculation and circulating cells in vivo We derived the functional capillary ratio (FCR) as a quantitative parameter for assessing the fraction of functional microvasculature in the pulmonary microcirculation and dead space.We identified that the FCR rapidly decreases in the early stage of sepsis-induced ALI. The intravital imaging revealed that this decrease resulted from the generation of dead space, which was induced by prolonged neutrophil entrapment within the capillaries. We further showed that the neutrophils had an extended sequestration time and an arrest-like dynamic behaviour, both of which triggered neutrophil aggregates inside the capillaries and arterioles. Finally, we found that Mac-1 (CD11b/CD18) was upregulated in the sequestered neutrophils and that a Mac-1 inhibitor restored the FCR and improved hypoxaemia.Using the intravital lung imaging system, we observed that Mac-1-upregulated neutrophil aggregates led to the generation of dead space in the pulmonary microcirculation that was recovered by a Mac-1 inhibitor in sepsis-induced ALI.


Assuntos
Lesão Pulmonar Aguda/etiologia , Pulmão/irrigação sanguínea , Antígeno de Macrófago 1/imunologia , Neutrófilos/citologia , Sepse/complicações , Lesão Pulmonar Aguda/patologia , Lesão Pulmonar Aguda/prevenção & controle , Animais , Anticorpos Monoclonais/farmacologia , Capilares , Modelos Animais de Doenças , Pulmão/diagnóstico por imagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microcirculação , Microscopia de Vídeo , Sepse/tratamento farmacológico , Sepse/patologia
6.
Small ; 14(50): e1803601, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30411856

RESUMO

Current nanoparticle (NP) drug carriers mostly depend on the enhanced permeability and retention (EPR) effect for selective drug delivery to solid tumors. However, in the absence of a persistent EPR effect, the peritumoral endothelium can function as an access barrier to tumors and negatively affect the effectiveness of NPs. In recognition of the peritumoral endothelium as a potential barrier in drug delivery to tumors, poly(lactic-co-glycolic acid) (PLGA) NPs are modified with a quinic acid (QA) derivative, synthetic mimic of selectin ligands. QA-decorated NPs (QA-NP) interact with human umbilical vein endothelial cells expressing E-/P-selectins and induce transient increase in endothelial permeability to translocate across the layer. QA-NP reach selectin-upregulated tumors, achieving greater tumor accumulation and paclitaxel (PTX) delivery than polyethylene glycol-decorated NPs (PEG-NP). PTX-loaded QA-NP show greater anticancer efficacy than Taxol or PTX-loaded PEG-NP at the equivalent PTX dose in different animal models and dosing regimens. Repeated dosing of PTX-loaded QA-NP for two weeks results in complete tumor remission in 40-60% of MDA-MB-231 tumor-bearing mice, while those receiving control treatments succumb to death. QA-NP can exploit the interaction with selectin-expressing peritumoral endothelium and deliver anticancer drugs to tumors to a greater extent than the level currently possible with the EPR effect.


Assuntos
Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Células Endoteliais/metabolismo , Nanopartículas/química , Ácido Quínico/química , Animais , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Feminino , Citometria de Fluxo , Células Endoteliais da Veia Umbilical Humana , Humanos , Neoplasias Mamárias Animais/tratamento farmacológico , Neoplasias Mamárias Animais/metabolismo , Camundongos , Camundongos Nus , Microscopia Confocal , Polímeros/química , Selectinas/química , Microambiente Tumoral/fisiologia
7.
Biomed Opt Express ; 9(5): 2383-2393, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29760995

RESUMO

Direct intravital imaging of an endothelial surface layer (ESL) in pulmonary microcirculation could be a valuable approach to investigate the role of a vascular endothelial barrier in various pathological conditions. Despite its importance as a marker of endothelial cell damage and impairment of the vascular system, in vivo visualization of ESL has remained a challenging technical issue. In this work, we implemented a pulmonary microcirculation imaging system integrated to a custom-design video-rate laser scanning confocal microscopy platform. Using the system, a real-time cellular-level microscopic imaging of the lung was successfully performed, which facilitated a clear identification of individual flowing erythrocytes in pulmonary capillaries. Subcellular level pulmonary ESL was identified in vivo by fluorescence angiography using a dextran conjugated fluorophore to label blood plasma and the red blood cell (RBC) exclusion imaging analysis. Degradation of ESL width was directly evaluated in a murine sepsis model in vivo, suggesting an impairment of pulmonary vascular endothelium and endothelial barrier dysfunction.

8.
PLoS One ; 12(11): e0187660, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29099870

RESUMO

Bone marrow is a vital tissue that produces the majority of erythrocytes, thrombocytes, and immune cells. Bone marrow transplantation (BMT) has been widely performed in patients with blood disorders and cancers. However, the cellular-level behaviors of the transplanted bone marrow cells over wide-areas of the host bone marrow after the BMT are not fully understood yet. In this work, we performed a longitudinal wide-area cellular-level observation of the calvarial bone marrow after the BMT in vivo. Using a H2B-GFP/ß-actin-DsRed double-transgenic mouse model as a donor, a subcellular-level nuclear-cytoplasmic visualization of the transplanted bone marrow cells was achieved, which enabled a direct in vivo dynamic monitoring of the distribution and proliferation of the transplanted bone marrow cells. The same spots in the wide-area of the calvarial bone marrow were repeatedly identified using fluorescently labeled vasculature as a distinct landmark. It revealed various dynamic cellular-level behaviors of the transplanted BM cells in early stage such as cluster formation, migration, and active proliferation in vivo.


Assuntos
Transplante de Medula Óssea , Medula Óssea/patologia , Diferenciação Celular , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Animais , Medula Óssea/diagnóstico por imagem , Linhagem da Célula , Citometria de Fluxo , Humanos , Estudos Longitudinais , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal
9.
Biomed Opt Express ; 6(10): 4154-64, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26504662

RESUMO

Lymph node (LN) is an important immune organ that controls adaptive immune responses against foreign pathogens and abnormal cells. To facilitate efficient immune function, LN has highly organized 3D cellular structures, vascular and lymphatic system. Unfortunately, conventional histological analysis relying on thin-sliced tissue has limitations in 3D cellular analysis due to structural disruption and tissue loss in the processes of fixation and tissue slicing. Optical sectioning confocal microscopy has been utilized to analyze 3D structure of intact LN tissue without physical tissue slicing. However, light scattering within biological tissues limits the imaging depth only to superficial portion of LN cortex. Recently, optical clearing techniques have shown enhancement of imaging depth in various biological tissues, but their efficacy for LN are remained to be investigated. In this work, we established optical clearing procedure for LN and achieved 3D volumetric visualization of the whole cortex of LN. More than 4 times improvement in imaging depth was confirmed by using LN obtained from H2B-GFP/actin-DsRed double reporter transgenic mouse. With adoptive transfer of GFP expressing B cells and DsRed expressing T cells and fluorescent vascular labeling by anti-CD31 and anti-LYVE-1 antibody conjugates, we successfully visualized major cellular-level structures such as T-cell zone, B-cell follicle and germinal center. Further, we visualized the GFP expressing metastatic melanoma cell colony, vasculature and lymphatic vessels in the LN cortex.

10.
Biomed Opt Express ; 6(6): 2158-67, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26114035

RESUMO

The number of circulating tumor cell (CTC) in the peripheral blood of cancer patients can be a valuable biomarker for cancer diagnosis and treatment monitoring. In this study, we implemented a custom-design video-rate confocal microscopy system in capable of direct visualization of fast flowing CTC at great saphenous vein (GSV) of a live animal model in vivo. Continuous acquisition of video-rate images at GSV revealed the highly dynamic time-dependent changes in the number of intravenously injected circulating tumor cells. By extracting a calibration factor through the hemocytometric analysis of intravenously injected long-circulating red blood cells, we established a novel quantitation method for CTC in whole body blood in vivo.

11.
Hepatology ; 61(6): 1978-97, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25627085

RESUMO

UNLABELLED: Tumor metastasis involves circulating and tumor-initiating capacities of metastatic cancer cells. Epithelial-mesenchymal transition (EMT) is related to self-renewal capacity and circulating tumor cell (CTC) characteristics for tumor metastasis. Although tumor metastasis is a life-threatening, complicated process that occurs through circulation of tumor cells, mechanistic aspects of self-renewal and circulating capacities have been largely unknown. Hepatic transmembrane 4 L six family member 5 (TM4SF5) promotes EMT for malignant growth and migration, so it was rationalized that TM4SF5, as a hepatocellular carcinoma (HCC) biomarker, might be important for metastatic potential. Here, self-renewal capacity by TM4SF5 was mechanistically explored using hepatocarcinoma cells with or without TM4SF5 expression, and we explored whether they became CTCs using mouse liver-orthotopic model systems. We found that TM4SF5-dependent sphere growth correlated with CD24(-) , aldehyde dehydrogenase (ALDH) activity, as well as a physical association between CD44 and TM4SF5. Interaction between TM4SF5 and CD44 was through their extracellular domains with N-glycosylation modifications. TM4SF5/CD44 interaction activated proto-oncogene tyrosine-protein kinase Src (c-Src)/signal transducer and activator of transcription 3 (STAT3)/Twist-related protein 1 (Twist1)/B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi1) signaling for spheroid formation, whereas disturbing the interaction, expression, or activity of any component in this signaling pathway inhibited spheroid formation. In serial xenografts using 200∼5,000 cells per injection, TM4SF5-positive tumors exhibited subpopulations with locally increased CD44 expressions, supporting for tumor cell differentiation. TM4SF5-positive, but not TM4SF5- or CD44-knocked-down, cells were identified circulating in blood 4-6 weeks after orthotopic liver injection using in vivo laser scanning endomicroscopy. Anti-TM4SF5 reagent blocked their metastasis to distal intestinal organs. CONCLUSION: TM4SF5 promotes self-renewal and CTC properties supported by TM4SF5(+) /CD44(+(TM4SF5-bound)) /ALDH(+) /CD24(-) markers during HCC metastasis.


Assuntos
Carcinoma Hepatocelular/metabolismo , Receptores de Hialuronatos/metabolismo , Neoplasias Hepáticas Experimentais/metabolismo , Proteínas de Membrana/metabolismo , Células Neoplásicas Circulantes/metabolismo , Animais , Proteína Tirosina Quinase CSK , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Complexo Repressor Polycomb 1/metabolismo , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Esferoides Celulares , Proteína 1 Relacionada a Twist/metabolismo , Quinases da Família src/metabolismo
12.
Biomacromolecules ; 16(1): 246-56, 2015 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-25514368

RESUMO

Renewable thermoset elastomers were prepared using the plant-based monomer carvomenthide. Controlled ring-opening transesterification polymerization of carvomenthide using diethylene glycol as an initiator gave α,ω-dihydroxyl poly(carvomenthide) (HO-PCM-OH), which was subsequently converted to carboxy-telechelic poly(carvomenthide) (HOOC-PCM-COOH) by esterification with excess succinic anhydride through a one-pot, two-step process, leading to no crystallinity, high viscosity, strong thermal resistance, and low glass transition temperature of the resulting functionalized polyester. Thermal curing processes of the resulting 3, 6, and 12 kg mol(-1) prepolymers were achieved with trifunctional aziridine to give cross-linked PCM elastomers. The thermal properties, mechanical behavior, and biocompatibility of the rubbery thermoset products were investigated by differential scanning calorimetry, thermal gravimetric analysis, dynamic mechanical analysis, tensile tests under static and cyclic loads, and cell adherence. These new materials are useful candidates to satisfy the design objective for the engineering of a variety of soft tissues.


Assuntos
Materiais Biocompatíveis/síntese química , Elastômeros/síntese química , Monoterpenos/química , Extratos Vegetais/química , Animais , Materiais Biocompatíveis/química , Varredura Diferencial de Calorimetria , Monoterpenos Cicloexânicos , Elastômeros/química , Etilenoglicóis , Técnicas In Vitro , Camundongos , Células NIH 3T3 , Anidridos Succínicos , Temperatura de Transição
13.
J Biomed Opt ; 18(3): 036005, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23462969

RESUMO

Lymph nodes (LN) are major checkpoints for circulating T lymphocytes to recognize foreign antigens collected from peripheral tissue. High endothelial venule (HEV) in LN facilitates the effective transmigration of circulating T lymphocytes from the blood into LN. There have been many efforts to visualize T lymphocytes trafficking across HEV to understand the underlying mechanism. However, due to insufficient spatiotemporal resolution and the lack of an in vivo labeling method, clear visualization of dynamic behaviors of rapidly flowing T lymphocytes in HEV and their transmigration have been difficult. In this work, we adapted a custom-designed video-rate laser scanning confocal microscopy system to track individual flowing T lymphocytes in the HEV in real time in vivo. We demonstrate that the HEVs in LN can be clearly identified in vivo with its distinctive cuboidal morphology of endothelial cells fluorescently labeled by intravenously injected anti-CD31 antibody conjugated with Alexa fluorophore. By visualizing the adaptively transferred T lymphocytes, we successfully analyzed dynamic flowing behaviors of T lymphocytes and their transendothelial migration while interacting with the endothelial cells in HEV.


Assuntos
Rastreamento de Células/métodos , Linfonodos/citologia , Linfócitos T/citologia , Animais , Células Endoteliais/química , Células Endoteliais/citologia , Eritrócitos/química , Eritrócitos/citologia , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Processamento de Imagem Assistida por Computador , Linfonodos/química , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Confocal , Microscopia de Vídeo , Modelos Biológicos , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Linfócitos T/química
14.
J Pharmacol Sci ; 109(2): 222-32, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19234365

RESUMO

The cardioprotective effects of KR-31761, a newly synthesized K+(ATP) opener, were evaluated in rat models of ischemia/reperfusion (I/R) heart injury. In isolated rat hearts subjected to 30-min global ischemia/30-min reperfusion, KR-31761 perfused prior to ischemia significantly increased both the left ventricular developed pressure (% of predrug LVDP: 17.8, 45.1, 54.2, and 62.6 for the control, 1 microM, 3 microM, and 10 microM, respectively) and double product (DP: heart rate x LVDP; % of predrug DP: 17.5, 44.9, 56.2, and 64.5 for the control, 1 microM, 3 microM, and 10 microM, respectively) at 30-min reperfusion while decreasing the left ventricular end-diastolic pressure (LVEDP). KR-31761 (10 microM) significantly increased the time to contracture during the ischemic period, whereas it concentration-dependently decreased the lactate dehydrogenase release during reperfusion. All these parameters were significantly reversed by 5-hydroxydecanoate (5-HD, 100 microM) and glyburide (1 microM), selective and nonselective blockers of the mitochondrial K+(ATP) (mitoK+(ATP)) channel and K+(ATP) channel, respectively. In anesthetized rats subjected to 30-min occlusion of left anterior descending coronary artery/2.5-h reperfusion, KR-31761 administered 15 min before the onset of ischemia significantly decreased the infarct size (72.2%, 55.1%, and 47.1% for the control, 0.3 mg/kg, i.v., and 1.0 mg/kg, i.v., respectively); and these effects were completely and almost completely abolished by 5-HD (10 mg/kg, i.v.) and HMR-1098, a selective blocker of sarcolemmal K+(ATP) (sarcK+(ATP)) channel (6 mg/kg, i.v.) administered 5 min prior to KR-31761 (72.3% and 67.9%, respectively). KR-31761 only slightly relaxed methoxamine-precontracted rat aorta (IC50: > 30.0 microM). These results suggest that KR-31761 exerts potent cardioprotective effects through the opening of both mitoK+(ATP) and sarcK+(ATP) channels in rat hearts with a minimal vasorelaxant effect.


Assuntos
Benzopiranos/uso terapêutico , Cardiotônicos/uso terapêutico , Indóis/uso terapêutico , Canais KATP/agonistas , Canais de Potássio/agonistas , Traumatismo por Reperfusão/tratamento farmacológico , Animais , Modelos Animais de Doenças , Técnicas In Vitro , Masculino , Mitocôndrias Cardíacas/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Sarcolema/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos
15.
Arch Pharm Res ; 31(4): 482-9, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18449506

RESUMO

The cardioprotective effects of KR-31762, a newly synthesized K+(ATP) opener, were evaluated in rat models of ischemia/reperfusion (I/R) heart injury. In isolated rat hearts subjected to 30-min global ischemia followed by 30-min reperfusion, KR-31762 (3 and 10 microM) significantly increased the left ventricular developed pressure (LVDP) and double product (heart rate x LVDP) after 30-min reperfusion in a concentration-dependent manner, while decreasing the left ventricular end-diastolic pressure (LVEDP). KR-31762 also significantly increased the time to contracture (TTC) during ischemic period (20.0, 22.4 and 26.4 min for control, 3 and 10 microM, respectively), while decreasing the release of lactate dehydrogenase (LDH) from the heart during 30 min reperfusion (30.4, 14.3 and 19.7 U/g heart weight, respectively). All these parameters except LDH release were reversed by glyburide (1 microM), a nonselective blocker of K+(ATP) channel, but not by 5-hydroxydecanoate, a selective blocker of mitoK+(ATP) channel. In anesthetized rats subjected to 45-min occlusion of left anterior descending coronary artery followed by 90-min reperfusion, KR-31762 significantly decreased the infarct size (60.8, 40.5 and 37.8% for control, 0.3 and 1.0 mg/kg, iv, respectively). KR-31762 slightly relaxed the isolated rat aorta precontracted with methoxamine (IC(50): 23.5 microM). These results suggest that KR-31762 exerts potent cardioprotective effects through the opening of sarcolemmal K(ATP) channel in rat hearts with the minimal vasorelaxant effects.


Assuntos
Benzopiranos/farmacologia , Cardiotônicos/farmacologia , Indóis/farmacologia , Canais KATP/agonistas , Moduladores de Transporte de Membrana/farmacologia , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miocárdio/metabolismo , Sarcolema/efeitos dos fármacos , Função Ventricular Esquerda/efeitos dos fármacos , Animais , Aorta/efeitos dos fármacos , Benzopiranos/uso terapêutico , Cardiotônicos/uso terapêutico , Ácidos Decanoicos/farmacologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Glibureto/farmacologia , Guanidinas/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Hidroxiácidos/farmacologia , Indóis/uso terapêutico , Canais KATP/metabolismo , L-Lactato Desidrogenase/metabolismo , Masculino , Moduladores de Transporte de Membrana/uso terapêutico , Metoxamina/farmacologia , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miocárdio/enzimologia , Miocárdio/patologia , Bloqueadores dos Canais de Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Sarcolema/metabolismo , Vasoconstritores/farmacologia , Vasodilatação/efeitos dos fármacos , Pressão Ventricular/efeitos dos fármacos
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