The protective effect of biphenyl dimethyl dicarboxylate (DDB) on chemically induced damages was studied in isolated suspended rat hepatocytes. The experimental results showed that DDB (200μg/106 cells) efficiently p...The protective effect of biphenyl dimethyl dicarboxylate (DDB) on chemically induced damages was studied in isolated suspended rat hepatocytes. The experimental results showed that DDB (200μg/106 cells) efficiently protected the hepatocytes against carbon tetrachloride (CC14 10 mrnol.L-1) and D-galactosamine (1 mmol.L-1) induced damages. Membranal lipid peroxidation (malondialdehyde, MDA formation) and glutamic pyruvic transaminase (GPT) release from the hepatocytes were markedly decreased. The damage of the cell surfaces of the hepatocytes were also reduced as seen under a scanning electron microscope (SEM). Pretreatment with DDB (300 mg-kg-1) orally ameliorated the reduction of liver glycogen and blood glucose caused by ip injection of D-galactosamine (800 mg-kg-1) in mice. When normal rats were given DDB 300 mg-kg-1 once daily for 10 d, the free ribosomal protein and RNA in the liver increased significantly. These results indicate that DDB is of beneficial effects on both damaged and normal hepatocytes.展开更多
AIM: To investigate the effects of taurolithocholate (TLC)on the canalicular motility in isolated rat hepatocyte cou-plets (IRHC).METHODS: TLC was added to IRHC at concentrationsof 10 and 50 μmol/L, respectively. In ...AIM: To investigate the effects of taurolithocholate (TLC)on the canalicular motility in isolated rat hepatocyte cou-plets (IRHC).METHODS: TLC was added to IRHC at concentrationsof 10 and 50 μmol/L, respectively. In each group, fi vetime-lapse movies containing 3 representative bile cana-liculi were taken under phase-contrast microscopy for12 h. The number of bile canalicular contractions andthe intervals between consecutive canalicular contrac-tions were calculated. Furthermore, the effects of TLC onIRHC were examined by transmission electron micros-copy.RESULTS: The bile canalicular contractions were spon-taneous and forceful in the controls. Active vesicularmovement was observed in the pericanalicular region.Immediately after the addition of TLC, the bile canaliculiwere deformed, and canalicular bile was incorporatedinto the vacuoles. The canaliculi were gradually dilated,and canalicular contractions were markedly inhibited byTLC. The vesicular movements became extremely slowin the pericanalicular region. The number of canalicularcontractions significantly decreased in the TLC-treatedgroups, as compared with that in the controls. The timeintervals were prolonged, as the TLC dosage increased,indicating that bile secretion into the canaliculi wasimpaired with TLC. Transmission electron microscopyrevealed the lamellar transformation of the canalicularmembranes in IRHC treated with TLC.CONCLUSION: TLC impairs both the bile canalicularcontractions and the canalicular bile secretion, possiblyby acting directly on the canalicular membranes in TLC-induced cholestasis.展开更多
Mequindox （MEQ）, 3-methyl-2-quinoxalinacetyl-l,4-dioxide, is widely used in Chinese veterinary medicine as an antimicrobial agent and feed additive. Its toxicity has been reported to be closely related to its metabo...Mequindox （MEQ）, 3-methyl-2-quinoxalinacetyl-l,4-dioxide, is widely used in Chinese veterinary medicine as an antimicrobial agent and feed additive. Its toxicity has been reported to be closely related to its metabolism. To understand the pathways underlying MEQ＇s metabolism more clearly, we studied its metabolism in isolated rat liver cells by using liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole orbitrap （LC-LTQ-Orbitrap） mass spectrometry. The structures of MEQ metabolites and their product ions were readily and reliably characterized on the basis of accurate MS2 spectra and known structure of MEQ. Eleven metabolites were detected in isolated rat liver cells, two of which were detected for the first time in vitro. The major metabolic pathways reported previously for in vitro metabolism of MEQ in rat microsomes were confirmed in this study, including N O group reduction, carbonyl reduction, and methyl monohydroxylation. In addition, we fotmd that acetyl hydroxylation was an important pathway of MEQ metabolism. The results also demonstrate that cellular systems more closely simulate in vivo conditions than do other in vitro systems such as microsomes. Taken together, these data contribute to our understanding of the in vivo metabolism of MEQ.展开更多
Studies were performed to determine the extent of nuclear DNA degradation induced by iron, iron-ascorbate, or iron-bleomycin under aerobic conditions in a model system using isolated rat liver nuclei. The effects of f...Studies were performed to determine the extent of nuclear DNA degradation induced by iron, iron-ascorbate, or iron-bleomycin under aerobic conditions in a model system using isolated rat liver nuclei. The effects of five antioxidants (catalase, superoxide dismutase, dimethyl sulfoxide, glutathione and diallyl sulfide) on this oxidative nuclear damage were also investigated. At the 0.05 level for statistical significance, iron induced concentration-dependent DNA degradation, and this effect was enhanced by ascorbate and bleomycin. The antioxidants catalase, dimethyl sulfoxide, and diallyl sulfide significantly reduced the iron-ascorbate-induced DNA damage, whereas superoxide dismutase and dimethyl sulfoxide significantly reduced iron-bleomycin-induced damage. Glutathione significantly increased the iron-bleomycin-induced DNA damage. These results suggest that the reactive oxygen species generated by iron, iron-ascorbate, and iron-bleomycin are responsible for the DNA strand breaks in isolated rat liver nuclei.展开更多
The effect of U50488, a selective K-opioid receptor agonist, on cardiac rhythm in the isolated perfused rat heart and intracellular calcium ([Ca2+] i) in the single ventricular myocyte were studied. The results showed...The effect of U50488, a selective K-opioid receptor agonist, on cardiac rhythm in the isolated perfused rat heart and intracellular calcium ([Ca2+] i) in the single ventricular myocyte were studied. The results showed that U50488 can induce arrhythmias dose-dependently in the isolated perfused rat heart and increase [ Ca2 + ] i in the single ventricular myocyte. The effect of U50488 can be blocked by a selectivek-receptor antagonist, nor-binaltorphimine. The arrhythmogenic effects and the increase of [ Ca2+]i induced by U50488 were blocked by U73122, neomycin and streptomycin, which are selective phospolipase C inhibitors, but not by U73433, the inactive structural analog of U73122. These results demonstrated that the arrhythmogenic effect of cardiac K-receptor is due to activation of phosphoinositol/Ca2+ pathway.展开更多
The isolation of a high yield and purity of Kupffer cells has been reported in detail.1 This paper reports into the research about isolation Kupffer cells from biopsy tissue of liver. This method includes 5 important ...The isolation of a high yield and purity of Kupffer cells has been reported in detail.1 This paper reports into the research about isolation Kupffer cells from biopsy tissue of liver. This method includes 5 important steps: (1) take fresh liver tissue, and mince with scissors. (2) spin at low speed to wash off red blood cells. (3) digest in collagenase for suitable time. (4) isolate Kupffer cells on a percoll density gradient. (5) cell charaterization was observed by N.S.E stain and peroxidatic activity with lumino-meter measurement and phagocytosis with latex beads.2.3展开更多
Myocardial ischemia is the most common and primary cause of myocardium damage. Numerous conventional techniques and methods have been developed for ischemia and reperfusion studies. However, because of damage to the h...Myocardial ischemia is the most common and primary cause of myocardium damage. Numerous conventional techniques and methods have been developed for ischemia and reperfusion studies. However, because of damage to the heart sample, most of these techniques can not be used to continuously monitor the full dynamic course of the myocardial metabolic pathway. The nuclear magnetic resonnance (NMR) surface coil technique, which overcomes the limitations of conventional instrumentation, can be used to quantitatively study every stage of the perfused heart (especially after perfusion stoppage) continuously, dynamically, and without damage under normal or designed physiological conditions at the molecular level. In this paper, 31 P NMR was used to study the effects of ischemia and hypoxia on isolated perfused hearts. The results show that complete hypoxia caused more severe functional damage to the myocardial cells than complete ischemia.展开更多
Direct effects of a high-dose aprotinin on the normally perfused hearts and the myocardial protection after ischemia and reperfusion were investigated in an isolated working rat heart model. In trial I, hearts had no ...Direct effects of a high-dose aprotinin on the normally perfused hearts and the myocardial protection after ischemia and reperfusion were investigated in an isolated working rat heart model. In trial I, hearts had no ischemia and were perfused with either K-H solution or the K-H solution containing aprotinin (200KIU/ml) for 55 min. No statistically significant difference was observed in hemodynamics betweem the two groups. In trial Ⅱ, hearts were exposed to 150 minperiod of global ischemia at 15℃ with 4℃ multidose St. Thomas'Ⅱ solution (STS). The control group I received norma1 K-H solution; the group Ⅱ was treated with the solution with aprotinin added. The group, was similar to the group Ⅰ and received the STS enriched with aprotinin. On reperfusion, the recovery of hearts in group, was significantly better than those of the group Ⅰand Ⅱ, as reflected by better hemodynamics and myocardial oxygen consumption,lower level myocardial enzymes, higher myocardial ATP levels and milder myocardial ultrastructural injury. There was no difference between the group Ⅰand Ⅱ. These results suggest that the aprotinin at a dose of 200 KIU/ml has no harmful effects on normally perfused hearts and has a marked myocardial protective effect on the prolonged myocardial ischemia when used in cold crystalloid cardioplegia.展开更多
Objective: To explore the protective effect of Cordyceps sinensis (CS) on nephrotoxicity of cyclosporine A (CsA) and its mechanism. Methods: The renal function of isolated perfused rats was observed before and after ...Objective: To explore the protective effect of Cordyceps sinensis (CS) on nephrotoxicity of cyclosporine A (CsA) and its mechanism. Methods: The renal function of isolated perfused rats was observed before and after three months' treatment by CS. Results: CS could improve the renal function, increase the volume of urine, Na＋ and K＋ excretion and inulin clearance rate, and reduce the resistance of renal per fusion. It was found that the activities of urinary N - acetyl-β- glucosaminidase (NAG), γ- glutamyl transferase (γ- GT) and lactate dehydrogenase (LDH) were lower in the CS treatment group than those in the control group. Conclusion: CS could protect the kidney from damage against nephrotoxicity of CsA and improve the abnormality of renal hemodynamics.展开更多
文摘The protective effect of biphenyl dimethyl dicarboxylate (DDB) on chemically induced damages was studied in isolated suspended rat hepatocytes. The experimental results showed that DDB (200μg/106 cells) efficiently protected the hepatocytes against carbon tetrachloride (CC14 10 mrnol.L-1) and D-galactosamine (1 mmol.L-1) induced damages. Membranal lipid peroxidation (malondialdehyde, MDA formation) and glutamic pyruvic transaminase (GPT) release from the hepatocytes were markedly decreased. The damage of the cell surfaces of the hepatocytes were also reduced as seen under a scanning electron microscope (SEM). Pretreatment with DDB (300 mg-kg-1) orally ameliorated the reduction of liver glycogen and blood glucose caused by ip injection of D-galactosamine (800 mg-kg-1) in mice. When normal rats were given DDB 300 mg-kg-1 once daily for 10 d, the free ribosomal protein and RNA in the liver increased significantly. These results indicate that DDB is of beneficial effects on both damaged and normal hepatocytes.
文摘AIM: To investigate the effects of taurolithocholate (TLC)on the canalicular motility in isolated rat hepatocyte cou-plets (IRHC).METHODS: TLC was added to IRHC at concentrationsof 10 and 50 μmol/L, respectively. In each group, fi vetime-lapse movies containing 3 representative bile cana-liculi were taken under phase-contrast microscopy for12 h. The number of bile canalicular contractions andthe intervals between consecutive canalicular contrac-tions were calculated. Furthermore, the effects of TLC onIRHC were examined by transmission electron micros-copy.RESULTS: The bile canalicular contractions were spon-taneous and forceful in the controls. Active vesicularmovement was observed in the pericanalicular region.Immediately after the addition of TLC, the bile canaliculiwere deformed, and canalicular bile was incorporatedinto the vacuoles. The canaliculi were gradually dilated,and canalicular contractions were markedly inhibited byTLC. The vesicular movements became extremely slowin the pericanalicular region. The number of canalicularcontractions significantly decreased in the TLC-treatedgroups, as compared with that in the controls. The timeintervals were prolonged, as the TLC dosage increased,indicating that bile secretion into the canaliculi wasimpaired with TLC. Transmission electron microscopyrevealed the lamellar transformation of the canalicularmembranes in IRHC treated with TLC.CONCLUSION: TLC impairs both the bile canalicularcontractions and the canalicular bile secretion, possiblyby acting directly on the canalicular membranes in TLC-induced cholestasis.
基金financially supported by the National Basic Research Program of China(2009CB118800)
文摘Mequindox （MEQ）, 3-methyl-2-quinoxalinacetyl-l,4-dioxide, is widely used in Chinese veterinary medicine as an antimicrobial agent and feed additive. Its toxicity has been reported to be closely related to its metabolism. To understand the pathways underlying MEQ＇s metabolism more clearly, we studied its metabolism in isolated rat liver cells by using liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole orbitrap （LC-LTQ-Orbitrap） mass spectrometry. The structures of MEQ metabolites and their product ions were readily and reliably characterized on the basis of accurate MS2 spectra and known structure of MEQ. Eleven metabolites were detected in isolated rat liver cells, two of which were detected for the first time in vitro. The major metabolic pathways reported previously for in vitro metabolism of MEQ in rat microsomes were confirmed in this study, including N O group reduction, carbonyl reduction, and methyl monohydroxylation. In addition, we fotmd that acetyl hydroxylation was an important pathway of MEQ metabolism. The results also demonstrate that cellular systems more closely simulate in vivo conditions than do other in vitro systems such as microsomes. Taken together, these data contribute to our understanding of the in vivo metabolism of MEQ.
文摘Studies were performed to determine the extent of nuclear DNA degradation induced by iron, iron-ascorbate, or iron-bleomycin under aerobic conditions in a model system using isolated rat liver nuclei. The effects of five antioxidants (catalase, superoxide dismutase, dimethyl sulfoxide, glutathione and diallyl sulfide) on this oxidative nuclear damage were also investigated. At the 0.05 level for statistical significance, iron induced concentration-dependent DNA degradation, and this effect was enhanced by ascorbate and bleomycin. The antioxidants catalase, dimethyl sulfoxide, and diallyl sulfide significantly reduced the iron-ascorbate-induced DNA damage, whereas superoxide dismutase and dimethyl sulfoxide significantly reduced iron-bleomycin-induced damage. Glutathione significantly increased the iron-bleomycin-induced DNA damage. These results suggest that the reactive oxygen species generated by iron, iron-ascorbate, and iron-bleomycin are responsible for the DNA strand breaks in isolated rat liver nuclei.
文摘The effect of U50488, a selective K-opioid receptor agonist, on cardiac rhythm in the isolated perfused rat heart and intracellular calcium ([Ca2+] i) in the single ventricular myocyte were studied. The results showed that U50488 can induce arrhythmias dose-dependently in the isolated perfused rat heart and increase [ Ca2 + ] i in the single ventricular myocyte. The effect of U50488 can be blocked by a selectivek-receptor antagonist, nor-binaltorphimine. The arrhythmogenic effects and the increase of [ Ca2+]i induced by U50488 were blocked by U73122, neomycin and streptomycin, which are selective phospolipase C inhibitors, but not by U73433, the inactive structural analog of U73122. These results demonstrated that the arrhythmogenic effect of cardiac K-receptor is due to activation of phosphoinositol/Ca2+ pathway.
文摘The isolation of a high yield and purity of Kupffer cells has been reported in detail.1 This paper reports into the research about isolation Kupffer cells from biopsy tissue of liver. This method includes 5 important steps: (1) take fresh liver tissue, and mince with scissors. (2) spin at low speed to wash off red blood cells. (3) digest in collagenase for suitable time. (4) isolate Kupffer cells on a percoll density gradient. (5) cell charaterization was observed by N.S.E stain and peroxidatic activity with lumino-meter measurement and phagocytosis with latex beads.2.3
文摘Myocardial ischemia is the most common and primary cause of myocardium damage. Numerous conventional techniques and methods have been developed for ischemia and reperfusion studies. However, because of damage to the heart sample, most of these techniques can not be used to continuously monitor the full dynamic course of the myocardial metabolic pathway. The nuclear magnetic resonnance (NMR) surface coil technique, which overcomes the limitations of conventional instrumentation, can be used to quantitatively study every stage of the perfused heart (especially after perfusion stoppage) continuously, dynamically, and without damage under normal or designed physiological conditions at the molecular level. In this paper, 31 P NMR was used to study the effects of ischemia and hypoxia on isolated perfused hearts. The results show that complete hypoxia caused more severe functional damage to the myocardial cells than complete ischemia.
文摘Direct effects of a high-dose aprotinin on the normally perfused hearts and the myocardial protection after ischemia and reperfusion were investigated in an isolated working rat heart model. In trial I, hearts had no ischemia and were perfused with either K-H solution or the K-H solution containing aprotinin (200KIU/ml) for 55 min. No statistically significant difference was observed in hemodynamics betweem the two groups. In trial Ⅱ, hearts were exposed to 150 minperiod of global ischemia at 15℃ with 4℃ multidose St. Thomas'Ⅱ solution (STS). The control group I received norma1 K-H solution; the group Ⅱ was treated with the solution with aprotinin added. The group, was similar to the group Ⅰ and received the STS enriched with aprotinin. On reperfusion, the recovery of hearts in group, was significantly better than those of the group Ⅰand Ⅱ, as reflected by better hemodynamics and myocardial oxygen consumption,lower level myocardial enzymes, higher myocardial ATP levels and milder myocardial ultrastructural injury. There was no difference between the group Ⅰand Ⅱ. These results suggest that the aprotinin at a dose of 200 KIU/ml has no harmful effects on normally perfused hearts and has a marked myocardial protective effect on the prolonged myocardial ischemia when used in cold crystalloid cardioplegia.
文摘Objective: To explore the protective effect of Cordyceps sinensis (CS) on nephrotoxicity of cyclosporine A (CsA) and its mechanism. Methods: The renal function of isolated perfused rats was observed before and after three months' treatment by CS. Results: CS could improve the renal function, increase the volume of urine, Na＋ and K＋ excretion and inulin clearance rate, and reduce the resistance of renal per fusion. It was found that the activities of urinary N - acetyl-β- glucosaminidase (NAG), γ- glutamyl transferase (γ- GT) and lactate dehydrogenase (LDH) were lower in the CS treatment group than those in the control group. Conclusion: CS could protect the kidney from damage against nephrotoxicity of CsA and improve the abnormality of renal hemodynamics.
