RESUMO
Proton nuclear magnetic resonance spectroscopy was performed on whole cells to study lipids and metabolites in Adriamycin- and Taxol-resistant K562 cells expressing multidrug resistance (MDR) and their sensitive counterparts. With one-dimensional spectra, both resistant cell lines showed lower fatty acid methylene:methyl ratios and higher choline:methyl ratios than sensitive cells. Using two-dimensional COSY spectra, a decrease in the glutamine content was evidenced in resistant cells. When these cells were maintained in culture medium without the drug, the fatty acid signals were partially recovered. Adriamycin-resistant K562 cells were also treated for 4 days with a high dose of verapamil, a MDR-reversing agent. The nuclear magnetic resonance spectra of verapamil-treated cells also showed partial recovery of fatty acid signals. These results could be paralleled with the reversion of the resistant phenotype, as evidenced by measuring the inhibiting concentration of Adriamycin and vinblastine in K562adr cells cultured without the drug or after short-term exposure to verapamil. Conversely, P-glycoprotein and mRNA expression and DNA amplification of the mdr gene were not modified when compared to resistant cells, suggesting that the MDR phenotype could be partially reversed independently of the mdr gene amplification and expression. These results demonstrate the role of lipids in the resistance phenomenon.
Assuntos
Antibióticos Antineoplásicos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Doxorrubicina/farmacologia , Resistência a Múltiplos Medicamentos/fisiologia , Leucemia Experimental/tratamento farmacológico , Leucemia Experimental/metabolismo , Lipídeos/análise , Paclitaxel/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/biossíntese , DNA de Neoplasias/genética , Resistencia a Medicamentos Antineoplásicos , Amplificação de Genes , Expressão Gênica , Humanos , Espectroscopia de Ressonância Magnética/métodos , RNA Mensageiro/genética , Células Tumorais Cultivadas , Vimblastina/farmacologiaAssuntos
Diacetil/análogos & derivados , Coração , Preservação de Órgãos/métodos , Polietilenoglicóis/farmacologia , Animais , Bicarbonatos/farmacologia , Cloreto de Cálcio/farmacologia , Soluções Cardioplégicas/farmacologia , Reativadores da Colinesterase/farmacologia , Diacetil/farmacologia , Coração/efeitos dos fármacos , Coração/fisiologia , Concentração de Íons de Hidrogênio , Magnésio/farmacologia , Espectroscopia de Ressonância Magnética , Masculino , Miocárdio/metabolismo , Perfusão/métodos , Fosfocreatina/metabolismo , Cloreto de Potássio/farmacologia , Ratos , Ratos Wistar , Cloreto de Sódio/farmacologia , Função Ventricular Esquerda/efeitos dos fármacosAssuntos
Soluções Cardioplégicas , Coração/fisiologia , Soluções para Preservação de Órgãos , Preservação de Órgãos , Adenosina , Alopurinol , Análise de Variância , Animais , Vasos Coronários/patologia , Vasos Coronários/fisiologia , Edema/prevenção & controle , Glutationa , Parada Cardíaca Induzida , Insulina , Espectroscopia de Ressonância Magnética , Masculino , Perfusão/métodos , Polietilenoglicóis , Rafinose , Ratos , Ratos Wistar , Fatores de Tempo , Função Ventricular EsquerdaAssuntos
Metabolismo Energético/efeitos dos fármacos , Rim , Soluções para Preservação de Órgãos , Preservação de Órgãos/métodos , Reperfusão , Trimetazidina/farmacologia , Adenosina , Trifosfato de Adenosina/metabolismo , Alopurinol , Animais , Glutationa , Insulina , Isquemia , Rim/irrigação sanguínea , Rim/fisiologia , Masculino , Rafinose , Ratos , Ratos WistarAssuntos
Criopreservação , Rim , Traumatismo por Reperfusão , Trimetazidina , Animais , Espectroscopia de Ressonância Magnética , Ratos , Ratos WistarRESUMO
We investigated changes in pHi during ischaemia-reperfusion of isolated rat hearts using phosphorus nuclear magnetic resonance spectroscopy (31P NMR). Hearts were separated into three groups according to the perfusion buffer: bicarbonate-buffered Krebs solution, HEPES-buffered Krebs solution, or bicarbonate-buffered Krebs solution plus 10(-6) M 5-(N-ethyl-N-isopropyl) amiloride (EIPA). In HEPES buffer and in bicarbonate buffer plus EIPA, pH at the end of 30 min of ischaemia and pH oscillations observed during early reperfusion were lower than in bicarbonate buffer. Thus, the presence of two pH regulation mechanisms (Na(+)-H+ antiport and Na(+)-HCO3- symport) was confirmed in the isolated rat heart, while in HEPES buffer, pH was regulated by Na(+)-H+ antiport, and in bicarbonate buffer plus EIPA, by Na(+)-HCO3- symport. When cardiac contraction was inhibited by 10 mM 2, 3-butanedione 2-monoxime (BDM), we observed, in all cases, a less pronounced decrease in pHi at the end of ischaemia, and in pHi oscillations at the onset of reperfusion. These effects were similar to those observed with 150 x 10(-8) M verapamil and might thus be related to a decrease in intracellular calcium. However, with BDM, a greater reduction in the pH recovery rate was observed only in HEPES buffer, suggesting a possible phosphatase-like effect affecting the Na(+)-H+ exchange. Whatever the buffer used, the protective effect of BDM was reflected by an increase in the rate pressure product, which was not observed with verapamil.
Assuntos
Diacetil/análogos & derivados , Coração/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Isquemia Miocárdica/metabolismo , Reperfusão Miocárdica , Miocárdio/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Bicarbonatos/metabolismo , Proteínas de Transporte/metabolismo , Diacetil/farmacologia , Coração/fisiologia , Coração/fisiopatologia , Técnicas In Vitro , Cinética , Espectroscopia de Ressonância Magnética , Masculino , Isquemia Miocárdica/fisiopatologia , Fosfocreatina/metabolismo , Ratos , Ratos Wistar , Simportadores de Sódio-Bicarbonato , Trocadores de Sódio-Hidrogênio/metabolismo , Fatores de Tempo , Verapamil/farmacologiaRESUMO
This study was undertaken to evaluate the effect of trimetazidine (TMZ) during cold storage (CS) and the consequence during normothermic reperfusion in an isolated perfused rat kidney model (IPK). IPK was used to assess the rate of perfusion flow, the ratio of ATP to inorganic phosphate (ATP/Pi) as a reflection of the energetic status during reperfusion, intracellular pH (pHi), tissue water content and malondialdehyde (MDA) tissue levels in four different preservation solutions after 48-hr preservation at 4 degreesC and 2-hr reperfusion at 37.5 degreesC: EuroCollins (EC), University of Wisconsin (UW), EC plus TMZ (10(-)6 M) (EC + TMZ) and UW plus TMZ (10(-)6 M) (UW + TMZ). When TMZ was added to the preservation solutions, perfusion flow rate (PFR) was significantly improved during reperfusion. Tissue water content, which reflected tissue edema, was significantly lower in TMZ groups than in groups without TMZ during both CS and reperfusion conditions. In TMZ groups, ATP/Pi ratio was also significantly improved during CS and reperfusion. In addition, TMZ lowered the pHi both during preservation and after reperfusion. MDA renal tissue level significantly decreased with TMZ both during the preservation period and after reperfusion. These overall results strongly suggested that TMZ contributes to renal protection from cold ischemia-reperfusion injury in this IPK model, especially when TMZ was added to UW solution and during prolonged hypothermic ischemia.