Pharmacokinetic and pharmacodynamic analysis of ferulic acid-puerarin-astragaloside in combination with neuroprotective in cerebral ischemia/reperfusion injury in rats

OBJECTIVE@#To investigate the effects of the active ingredients combined therapy on inflammatory factors interleukin 1 beta (IL-1β) and neuropeptide Y (NPY) based on pharmacodynamics in rats.@*METHODS@#The animal model was built by transient middle cerebral artery occlusion (MCAO). The method for evaluating the concentrations of the FA-Pr-Al components in rat plasma was established by using HPLC and the expression levels of IL-1β and NPY were determined by ELISA. A new mathematics method of the trend of percentage rate of change (PRC) was used to assess the correlation between pharmacokinetics (PK) and pharmacodynamics (PD).@*RESULTS@#FA-Pr-Al in combination reduced neurological deficits, decreased infarct volume and inhibited the expression levels of IL-1β and NPY (all P<0.05) compared with the model group. FA, Pr and Al all displayed two compartment open models in rats. Clockwise hysteresis loops were obtained by time-concentration-effect curves. IL-1β and NPY level changes in the plasma followed an opposite trend to the plasma concentration tendency after Cmax was reached. Astragaloside's PRC value was significantly higher than those of FA and puerarin between 120 to 180 min.@*CONCLUSIONS@#The pharmacokinetics of FA-Pr-Al in combination were closely related its pharmacodynamics in treating ischemia/reperfusion injury, and the components of FA-Pr-Al may have a synergistic pharmacological effect. Astragaloside may play a more pronounced role in regulating IL-1βand NPY levels compared with puerarin or FA.

Pharmacokinetic and pharmacodynamic analysis of ferulic acid-puerarin-astragaloside in combination with neuroprotective in cerebral ischemia/reperfusion injury in rats

Objective: To investigate the effects of the active ingredients combined therapy on inflammatory factors interleukin 1 beta (IL-1β) and neuropeptide Y (NPY) based on pharmacodynamics in rats. Methods: The animal model was built by transient middle cerebral artery occlusion (MCAO). The method for evaluating the concentrations of the FA-Pr-Al components in rat plasma was established by using HPLC and the expression levels of IL-1β and NPY were determined by ELISA. A new mathematics method of the trend of percentage rate of change (PRC) was used to assess the correlation between pharmacokinetics (PK) and pharmacodynamics (PD). Results: FA-Pr-Al in combination reduced neurological deficits, decreased infarct volume and inhibited the expression levels of IL-1β and NPY (all Pmax was reached. Astragaloside's PRC value was significantly higher than those of FA and puerarin between 120 to 180 min. Conclusions: The pharmacokinetics of FA-Pr-Al in combination were closely related its pharmacodynamics in treating ischemia/reperfusion injury, and the components of FA-Pr-Al may have a synergistic pharmacological effect. Astragaloside may play a more pronounced role in regulating IL-1βand NPY levels compared with puerarin or FA.

Characteristics of microsomal phase II metabolic enzymes in mouse embryonic stem cell-derived liver tissue / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the characteristics of phase II metabolic enzymes in mouse embryonic stem (ES) cell-derived liver tissue.</p><p><b>METHODS</b>Mature hepatocytes were differentiated from embryonic stem cells in cultured mouse embryoid bodies (EB) at d18. Western blot was used to detect the expression of uridine 5'-diphosphate glucronosyl transferase (UGT1a1,UGT1a6) and microsomal glutathione S-transferases 1(mGST1) during the differentiation course.The derived liver tissue was incubated with UDPGA and 7-HFC,the formation of 7-HFC glucuronide was detected by HPLC to examine the total activities of UGT1a1 and UGT1a6. Furthermore, the microsomes were incubated with CDNB and GSH,and the mGST1 activity was measured by spectrometry.</p><p><b>RESULTS</b>An increase tendency of UGT1a1 expression was noticed during the differentiation course. UGT1a6 and mGST1 were not detected in the earlier stage until d18 of differentiation. The metabolic activity of mGST1 in the derived hepatocytes was 7.65 nmol/min/mg on d18.</p><p><b>CONCLUSION</b>The ES cell-derived liver tissue possesses partial metabolic function of phase II enzymes on d18 of differentiation,which might be used as a model for in vitro research on hepatic pathophysiology and phase II drug metabolism.</p>

Expression of Junctophilin 1 during cardiogenesis of mouse embryonic stem cells and rat embryos / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the expression of Junctophilin 1 (JP1) in cardiogenesis of mammalian.</p><p><b>METHODS</b>Cardiac differentiation of embryonic stem cells (ESCs) was generated by hanging drop method. Fetal heart was obtained from the rats aged d 14-20 of gestation. The expression of JP1 and JP2 during cardiogenesis of ESCs and rat embryos was analyzed by RT-PCR or Western blotting. Immunofluorescence staining was employed to reveal the distribution of JP1 and JP2 in embryoid body (EB), probing for merging of JP1 and JP2 and cardiac sarcomeric α-Actinin or Troponin-T. Percentage of JP1 and JP2-positive staining cells was analyzed quantitatively by FCS on d17.</p><p><b>RESULTS</b>JP1 mRNA was up-regulated at the early stage (d 5-11) and then decreased. The expression of JP1 protein was up-regulated at the early stage (d 7-9), then decreased gradually and disappeared after d 15. While JP2 gene and protein expression increased in a time-dependent manner during cardiogenesis of rat embryos. The results of immunofluorescence staining showed that there was a parallel co-localization of JP2 with Troponin-T or α-Actinin on d17, while JP1 failed to express in the sarcomeric positive area at the same time point. Furthermore, FCS analysis showed that about 16.59% of cells were JP2-positive, while no cells were stained positively for JP1 in d17 EBs.</p><p><b>CONCLUSION</b>JP1 gene is expressed during the whole process of cardiogenesis, while JP1 protein only appears on the early stage. The expression of JP1 in cardiogenesis of ESCs is consistent with that of rat embryos.</p>

Phenotype-based primary screening for drugs promoting neuronal subtype differentiation in embryonic stem cells with light microscope / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To set up a platform for phenotype-based primary screening of drug candidates promoting neuronal subtype differentiation in embryonic stem cells (ES) with light microscope.</p><p><b>METHODS</b>Hanging drop culture 4-/4+ method was employed to harvest the cells around embryoid body (EB) at differentiation endpoint. Morphological evaluation for neuron-like cells was performed with light microscope. Axons for more than three times of the length of the cell body were considered as neuron-like cells. The compound(s) that promote neuron-like cells was further evaluated. Icariin (ICA, 10(-6)mol/L) and Isobavachin (IBA, 10(-7)mol/L) were selected to screen the differentiation-promoting activity on ES cells. Immunofluorescence staining with specific antibodies (ChAT, GABA) was used to evaluate the neuron subtypes.</p><p><b>RESULTS</b>The cells treated with IBA showed neuron-like phenotype, but the cells treated with ICA did not exhibit the morphological changes. ES cells treated with IBA was further confirmed to be cholinergic and GABAergic neurons.</p><p><b>CONCLUSION</b>Phenotypic screening with light microscope for molecules promoting neuronal differentiation is an effective method with advantages of less labor and material consuming and time saving, and false-positive results derived from immunofluorescence can be avoided. The method confirms that IBA is able to facilitate ES cells differentiating into neuronal cells, including cholinergic neurons and GABAergic neurons.</p>

Establishment of optimized neuronal differentiation-promoting model derived from P19 embryonic carcinoma cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To establish an optimized primary drug screen model of neuronal differentiation using P19 embryonal carcinoma cells.</p><p><b>METHODS</b>The final concentration of retinoid acid (RA), days of suspension culture, manner of adherent culture, suitable cell density and adherent culture medium were tested, respectively. Two stages of neuronal differentiation were examined based on morphological changes and immunocytochemistry analysis of neuronal specific protein β-tubulin III.</p><p><b>RESULTS</b>On d 8 of differentiation culture, neuron-like cells were observed with final concentration of 1 μmol/L RA. Neuron-like network was formed on d 16 of neuronal differentiation. β-tubulin III was positively stained on both stages, indicating P19 cells were differentiated into neurons.</p><p><b>CONCLUSION</b>The model using RA to induce P19 embryonic carcinoma cells to differentiate into neuron-like cells has been successfully established, which may provide a rapid, phenotypic cell-based platform for primary screening of neurogenesis-promoting drugs.</p>

Ginsenoside Rg1 antagonizes β-amyloid peptide-induced apoptosis in primarily cultured rat neurons via mitochondrial pathway / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the neuroprotective effects of ginsenoside Rg1 against β-amyloid peptide (Aβ(25-35))-induced apoptosis in primarily cultured rat cortical neurons.</p><p><b>METHODS</b>Primarily cultured cortical neurons were obtained from embryonic (E18d) rat fetus and maintained in neurobasal medium for 7d. Primary neurons pretreated with 1 μmol/L, 10 μmol/L or 20 μmol/L Rg1 for 24 h were challenged with 10 μmol/L Aβ(25-35) for 72 h. Morphological changes of neurons were evaluated; mitochondrial membrane potential (ΔΨm) was measured; with JC-1 staining and the expression of neural apoptosis-related proteins was detected by Western blot analysis.</p><p><b>RESULTS</b>Exposure to Aβ(25-35) for 72 h caused serious neural cell insults. A pretreatment with Rg1 significantly reduced Aβ(25-35)induced cell death in a dose-dependent manner, with a maximal effect (-90%) obtained at 20 μmol/L. The JC-1 staining results demonstrated the loss of ΔΨm after Aβ(25-35) treatment, while Rg1 maintained the normal level of ΔΨm. A series of mitochondrion-mediated apoptotic events happened after Aβ(25-35) treatment, such as decrease of Bcl-2/Bax, release of cytochrome C and activation of caspase 9 and caspase 3, which were all blocked by Rg1 pretreatment. Both estrogen receptor (ER) antagonist ICI182, 780 and glucocorticoid receptor (GR) antagonist RU486 blocked the antiapoptotic effects of Rg1.</p><p><b>CONCLUSION</b>Ginsenoside Rg1 protects primary cultured rat cortical neurons from Aβ(25-35)-induced injury, which may be associated with mitochondrion-mediated antiapoptosis pathway.</p>

Effect of chronic lead exposure on expression of autophagy-associated proteins in rat hippocampus / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of chronic lead exposure on expression of autophagy-associated proteins in rat hippocampus.</p><p><b>METHODS</b>SD rats were randomly divided into three groups: control group was given distilled water, lead-exposed groups were given 0.5 g/L (low-dose) or 2.0 g/L(high-dose) lead acetate solution in drinking water. The rat pups started to drink the lead content water until 60 d maturity. The lead contents in blood and brain samples were analyzed by graphite furnace atomic absorption spectrophotometry. The expressions of Beclin 1, LC3, LAMP2 and cathepsin B proteins were detected by Western blot and immunohistochemistry.</p><p><b>RESULTS</b>Compared with control group, the contents of lead were significantly higher in blood and hippocampus samples in chronic lead-exposed rats (P<0.01). Western blot showed that the expression of Beclin 1 and LC3-II/LC3-I increased significantly in high dose lead-exposed group compared with control group (P<0.05 or P<0.001). The confocal laser immunostaining results demonstrated that increased immunofluorescence staining of cathepsin B in hippocampal neurons compared with control animals.</p><p><b>CONCLUSION</b>The disturbance of autophagy-lysosome signaling molecules might be partially contribute to neurotoxicity of chronic lead exposure.</p>

4, 8-disubstituted-8, 9-dihydro-pyrazine2,3-gquinazoline-7(6H)-ketones: a novel class of antitumor agents / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the antitumor activity of a novel class of 4, 8-Disubstituted-8, 9-dihydropyrazine[2, 3-g]quinazoline-7(6H)-ketones in vitro, and to screen potential anticancer compounds for further study.</p><p><b>METHODS</b>Seventeen compounds of 4, 8-Disubstituted-8, 9-dihydropyrazine[2, 3-g]quinazoline-7(6H)-ketones were synthesized with solid-phase method for biological evaluation of EGFR tyrosine kinase. MTT method was used to evaluate the cytotoxic activity in vitro against three human cancer cell lines (human lung carcinoma cell line A549, human leukemia cell lines K562 and human gastric carcinoma cell line SGC7901).</p><p><b>RESULTS</b>Compound 7-13 and 7-14 showed potent antitumor activities against A549 cells, with IC(50) values of 8.10 and 8.12 mol/L, respectively. Eight compounds showed proliferative inhibition effect on K562 cells, especially 7-2, 7-13 and 7-17, with IC(50) values of 2.22,0.57 and 7.20 mol/L,respectively.And compound 7-13 and 7-3 showed potent antitumor activity against SGC7901 cells, with IC(50) values of 4.20 and 9.71 mol/L, respectively.</p><p><b>CONCLUSION</b>The synthesized compounds 4, 8-Disubstituted-8, 9-dihydropyrazine[2, 3-g] quinazoline-7(6H)-ketones show inhibition effects on human cancer cell lines in vitro. Compound 7-13 has anticancer activity in all three cancer cell lines, which might be used as a potential antitumor drug for further study.</p>

Transcription of cytoskeleton protein genes in differentiation of neurons from mouse embryonic stem cells induced by small molecules / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the transcription of cytoskeleton protein genes in differentiation of neurons from mouse embryonic stem (ES) cells induced by all-trans retinoic acid (RA), and to explore the possibility of setting up a method to screen small molecules with promoting or inhibiting effect.</p><p><b>METHODS</b>The hanging drop method was employed for embryonic body formation to mimic embryo development in vivo. Reverse transcriptase PCR (RT-PCR) was performed to investigate mRNA expression of the neuron-specific cytoskeleton proteins including Mtap2, Nefm and beta-tubulin III which were regarded as the inducing effect indexes of RA. Morphological evaluation and immunocytochemistry staining were conducted to identify the neural derivatives. Moreover, the inducing effects of six synthetic molecules were further evaluated.</p><p><b>RESULT</b>RA up-regulated the mRNA expression of Mtap2 and Nefm, especially Mtap2 increased by 1.27 times, which was consistent with the morphological alteration. However, there was no significant changes of beta-tubulin III expression. With addition of the six synthetic molecules, the transcription of Mtap2 was inhibited, while the Nefm mRNA expression was up-regulated in some degree, especially for molecule 1 and 3 that was increased by 1.4 and 1.2 times, which, however, was not parallel to the morphological changes.</p><p><b>CONCLUSION</b>The transcriptional levels of Mtap2 and Nefm are both up-regulated in the RA-induced differentiation of ES cells towards neurons. The up-regulation of Mtap2 is consistent with the morphological alteration, which might be the key landmark in the RA-induced differentiation of ES cells into neurons.</p>

Effect of concanavalin A on expression of MAPEG mRNA in Balb/c mouse brain / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the gene expression of MAPEG in the cortex of concanavalin A (Con A)-induced mouse immune inflammatory model and the effect of cyclosporine A (Cs A).</p><p><b>METHODS</b>Male Balb/c mouse immune inflammation model was developed by intravenous injection of Con A (20 mg/kg). Cs A (150 mg/kg) was intravenously infected prior to Con A administration. The MAPEG expressions were determined by RT-PCR.</p><p><b>RESULT</b>mGST1, mGST3, LTC(4)S, FLAP and mPGES-1 were detected by RT-PCR but not mGST2. Eight hours after Con A treatment, mGST1 level was up-regulated to 1.2 approximately 1.5 folds of control with or without Cs A treatment. mGST3ìLTC(4)S, FLAP and mPGES-1 mRNA levels were not influenced by Con A administration.</p><p><b>CONCLUSION</b>Immune mechanism may be not involved in mGST1 up-regulation in this model and Con A does not alter arachidonic acid metabolism in cortex.</p>

Effect of Rongshi granule on renal stone formation and osteopontin expression in rat urolithiasis model / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effect of Rongshi granule on osteopontin(OPN) expression.</p><p><b>METHOD</b>The urlisthiasis rats were induced by ethylene glycol (EG) and ammonium chloride, the control group rats were non-treated, and the Rongshi granule groups (low-dose group, middle-dose group and high-dose group) were administered Rongshi granule in addition to EG and ammonium chloride in 21 days. Pooled 24 h urine samples from each group were collected weekly with the use of metabolic cages, the concentration of uric calcium and oxalic acid were respectively measured by EDTA and photoelectric colorimetric method. Eight animals from each group were killed at 0, 7, 14, and 21 days, kidneys were histologic examinaed and immunohistochemical staining.</p><p><b>RESULT</b>The expression of kidney osteopontin in model group was obviously higher than that of control group (P <0.01), and was up to the highest at 21 days with 1.4 times (0.281 3/0.201 8) of the control group. The expression of kidney osteopontin in all of the Rongshi granule groups were lower than those of model group (P < 0.05), with an obvious dose-dependent manner. The degree of the kidney calcium oxalate crystal of the rats in all the Rongshi granule groups was much lower than that of model group, and the uric calcium and oxalic acid were much lower than those of model group (P < 0.01).</p><p><b>CONCLUSION</b>The Rongshi granule could inhibit the expression of osteopontin in rat urolithiasis model.</p>

Estrogenic activity and its mechanism of ethanol extract from black soybean / 中国中药杂志

<p><b>OBJECTIVE</b>To explore the estrogenic activity and its mechanism of ethanol extract from black soybean (BSE).</p><p><b>METHOD</b>The modified MCF-7 cell proliferation assay was used to evaluate the estrogenic activity of BSE. And the possible mechanisms were addressed using RT-PCR measurements in which pure estrogen receptor antagonist ICI182,780 was employed as a tool.</p><p><b>RESULT</b>The estrogenic activity of BSE at various concentrations (1-1000 microg x mL(-1)), expressed as proliferative effect (PE) relative to that of solvent control, was examined. The results indicated that, at low concentration range (10-200 microg x mL(-1)), BSE was able to induce MCF-7 cell growth with a maximum at 100 microg x mL(-1). The results of RT-PCR showed that pS2 and PR mRNA could be significantly induced by BSE in MCF-7 cells, which was relative to the concentration of BSE. Moreover, the specific estrogen receptor antagonist, ICI182,780 could block these reactions.</p><p><b>CONCLUSION</b>Ethanol extract of black soybean can stimulate the growth of MCF-7 cells and increase the expression of estrogen receptor-responsive gene, suggesting that the estrogenic effects of BSE are mediated by the estrogen receptor.</p>

Preparation of two derivatives from icariin and investigation of their estrogen-like effects / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the estrogen-like activities of icariin (ICA), icaritin (ICT) and desmethylicaritin (DICT) and their structure/activity relationships.</p><p><b>METHODS</b>ICT was hydrolyzed from ICA by cellulase and then DICT was demethylated from ICT in boron tribromide and dichloromethane system. Estrogen-sensitive MCF-7 cells and T47D cells were co-incubated with different concentrations of test compounds for 6 and 9 d respectively, and the cell proliferation was measured by MTT.</p><p><b>RESULTS</b>ICT and DICT both markedly enhanced cell proliferation. Compared with estradiol (10.(-9) mol/L), the proliferative effects of 10.-6 mol/L ICT and DICT on MCF-7 cells were 90.0% and 94.0% (P<0.01), respectively, and those of T47D cells were 65.6% and 50.0%. (P<0.01). But this phenomenon was not observed with ICA. Cell proliferation induced by ICT and DICT was completely antagonized by 10.(-7 )mol/L pure estrogen receptor antagonist, ICI182,780.</p><p><b>CONCLUSION</b>ICT and DICT possess estrogen-like activity of enhancing proliferation in MCF-7 and T47D cells. However, ICA appears to have no estrogenicity on MCF-7 and T47D cell lines in vitro.</p>

Chemical constituents from Elsholtzia blanda / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the constituents of Elsholtzia blanda.</p><p><b>METHOD</b>The chemical components were isolated by polyamide and silica gel column chromatography. Their structures were identified with extensive spectral (EI-MS, ESI-MS, 1H-NMR, 13C-NMR, DEPT, 1H-1H-COSY, HMBC, HMQC) and chemical methods.</p><p><b>RESULT</b>Five compounds were isolated and identified as luteolin (I), luteolin-5-O-beta-D-glucopyranoside (II), luteolin-7-O-beta-D-glucopyranoside (III), 5-hydroxy-7, 8 -dimethoxyflavone (IV) and 5-hydroxy-6, 7-dimethoxyflavone (V).</p><p><b>CONCLUSION</b>Compounds III, IV, V were isolated from E. blanda for the first time and I was firstly separated from the genus Elsholtzia.</p>

Contragestazol (DL111-IT) inhibits proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To evaluate the antiproliferative activity of contragestazol (DL111-IT) on the human prostate cancer cell line PC3 in vitro and in vivo and to elucidate its potential molecular mechanisms.</p><p><b>METHODS</b>The cell killing ability of DL111-IT was measured by the 3-(4,5-dimethylthia-zol,2-yl)-2,5-diphenyltetrazolium bromide (MTT) reagent assay method and the tumor xenograft model. The cell cycle was analyzed by flow cytometry and protein expression, including retinoblastoma (pRb), cyclin-dependent kinase 4 (CDK4) and cyclin D1, was detected by Western blotting.</p><p><b>RESULTS</b>DL111-IT exhibited high efficiency on cell growth inhibition of the human androgen-independent prostate cancer cell line PC3. The drug concentration that yielded 50% cell inhibition (IC50 value) was 9.9 mg/mL. In the PC3 tumor xenograft study, DL111-IT (1.25 mg/kg-20.0 mg/kg) given once a day for 10 days significantly inhibited tumor growth, with the inhibition rate ranging from 21% to 50%. Flow cytometric analysis indicated that DL111-IT could cause G1 arrest in the PC3 cell line, but not apoptosis. DL111-IT enhanced pRb expression and down-regulated CDK4 and cyclin D1 expression, suggesting that cell cycle regulation might contribute to the anticancer property of DL111-IT.</p><p><b>CONCLUSION</b>DL111-IT inhibits the proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo by a cell cycle regulation pathway.</p>

Establishment of BCG combined LPS-induced hepatocyte immunotoxicity model to assess liver protective effects / 浙江大学学报·医学版

OBJECTIVE: To establish a hepatocyte immunotoxicity model for screening of liver protective medications. METHODS: Cytotoxicity was induced by coincubating BCG-pretreated rat hepatocytes in vivo and with 10 mg/L LPS in vitro. Biphenyldimethylesterate (DDB), malotilate(MLT), silybin(SB) and glycyrrhizin (GRZ) were coincubated along with LPS to prevent the hepatocyte injury and verify the applicability and reliability of the model. AST, LDH and nitric oxide (NO) were measured in both the serum and supernatant. The liver and spleen index were calculated and the liver histopathologic changes were examined microscopically. RESULTS: Supernatant AST, LDH and NO in the BCG combined LPS group were increased in comparison with the control group (P<0.01). This increase was attenuated by the addition of DDB, MLT, SB and GRZ (P<0.05). The serum AST, NO and liver and spleen index were also increased significantly compared with the control group (P<0.01). Microscopic exam revealed serious histopathologic changes in the BCG combined LPS group. Hepatoxicity with associated liver enzyme elevation but histopathologic changes were attenuated by DDB, MLT, SB and GRZ. CONCLUSION: BCG combined LPS-induced hepatocyte immunotoxicity in an in vitro rat model may be a useful technique to assess the effectiveness of liver protective medications.

Signal transduction pathways induced by nitric oxide in rat hepatocytes / 浙江大学学报·医学版

OBJECTIVE: To study signal transduction pathways in cultured rat hepatocytes in the high nitric oxide (NO) environment of hepatitis. METHODS: NO levels were assessed by measurement of its stable oxidative products nitrite (NO2(-)) and nitrate (NO3(-)) using the Griess method with or without thiols (GSH or L-Cys). Rat hepatocytes were incubated with Sodium Nitroprusside (SNP) to produce a high NO environment and the intracellular cGMP and s-nitrosoglutathione (GSNO) in the culture media were measured using radioimmunoassay or with the MTT assay absorbed at 334nm respectively. RESULTS: After incubation of 1.543 mmol/L SNP for 30 minutes 0.63+/-0.06 mmol/L and at 25 minutes 0.98+/-0.11 mmol/L of NO was released in containing 25 mmol/L GSH and L-Cys condition. The levels of both cGMP and GSNO were significantly increased (compared with control P<0.05) in a dose related manner. CONCLUSION: Signal transduction of cultured rat hepatocytes in a high NO environment could be a cGMP-dependent as well as a non-cGMP-dependent pathway.

Augmentation of rat liver microsome glutathione S-transferase preparation / 浙江大学学报·医学版

OBJECTIVE: To investigate the augmentation of microsomal glutathione S-transferase (mGST) preparation using simple organic compounds. METHODS: Rat liver microsomes were isolated using both the polyethyleneGlyco 6000 (PEG6000) and Ca(2+) precipitation methods. Next the mGST activity was measured after incubation with the alkylating agent N-ethylmaleimind (NEM). RESULTS: The baseline mGST activity of rat microsomes was 0.15 after PEG6000 exposure and 0.082 after Ca(2+) precipitation. After NEM treatment mGST activity increased to 1.797 (2.35X) (P<0.01) and 2.375 (4.127X) (P<0.01) respectively followed by purified washing. mGST activation was stimulated maximally by 5-10 mmol/L NEM and occurred rapidly with 1-2 min of co- incubation. CONCLUSION: For both the PEG6000 and Ca(2+) precipitation methods the mGST activity of rat microsomes can be significantly enhanced after exposure to NEM. This enhancement is more prominent with the Ca(2+) precipitation.