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Li-shi Zhang

Publications and source records attributed to Li-shi Zhang.

18 recordsLinked to original sources
PubMed2006

[Effect of soy isoflavone on gene expression of leptin and insulin sensibility in insulin-resistant rats].

OBJECTIVE: To explore the effects of soy isoflavone (SIF) on gene expression of leptin and insulin sensibility in insulin-resistant (IR) rats induced by high-fat, and to reveal the mechanisms of SIF in ameliorating insulin sensibility. METHODS: IR rats were randomly divided into four groups based on their insulin-resistant indexes (IRI): one model control group and three SIF groups that were gavaged with water solutions with SIF at doses of 0 mg/kg, 50 mg/kg, 150 mg/kg, and 450 mg/kg, respectively. After one month, fasting glucose, fasting insulin, leptin in serum, and leptin mRNA in the perirenal adipocyte were detected by enzymic method, radioimmunoassay, enzyme linked immunosorbent assay, and real time quantitative RT-PCR, respectively. RESULTS: The model control group was used to compare against the other groups: (1) Insulin and IRI were lower in the 150 mg/kg and 450 mg/kg groups; (2) In the 450 mg/kg group, body weight and leptin mRNA expression were lower, serum leptin content was higher. CONCLUSION: These results indicate that soy isoflavone might decrease body weight of rats and leptin mRNA, increase serum leptin level, and ameliorate leptin and insulin sensitivities.

Animals↗
PubMed2006

[Evaluation of the genotoxicity of vincristine and colchicine using mouse lymphoma tk mutation assay].

OBJECTIVE: To evaluate the genotoxicity of two mitotic inhibitors vincristine and colchicine, and to compare the detecting sensitivity of tk gene mutation assay with short-and long-term treatment by them. METHODS: Tk gene mutation assay was performed by microwell method with L5178Y mouse lymphoma cell line after exposing to vincristine and colchicine for 3 h and 24 h respectively, and the results of two different treating time were compared. RESULTS: The two chemicals didn't show positive responses in mouse lymphoma assay (MLA) with 3h treatment, but they could induce tk mutation frequency increase 1.6 to 4.8 and 2.1 to 6.2 times higher to spontaneous MF respectively after continuous treatment for 24 h. CONCLUSION: Vincristine and colchicine had mutagenic effect on tk gene with long-term treatment, which indicated that the detecting sensitivity of MLA could be enhanced by long-term treatment.

Animals↗
PubMed2006

[Effects of soy isoflavone on low-grade inflammation in obese rats].

OBJECTIVE: To explore the effects of soy isoflavone (SIF) on low-grade inflammation in obese rats induced by high-fat diet, and to elucidate mechanisms of SIF in improving insulin sensitivity. METHODS: Obese rats were randomly divided into 4 groups: One model control group and 3 SIF groups that were given water solutions with SIF at 0 mg/(kg x d), 50 mg/(kg x d), 150 mg/(kg x d), and 450 mg/(kg x d), respectively. After one month, fasting glucose, fasting insulin, interleukin-6, tumor necrosis factor-alpha, C-reactive protein, resistin, and adiponectin in serum were detected by enzymic method, radioimmunoassay, and enzyme linked immunosorbent assay, respectively. RESULTS: In the 150 mg/(kg x d) group and 450 mg/(kg x d) group, fasting body-weights, viscera fatty deposition, and contents of insulin, interleukin-6, and tumor necrosis factor-alpha in serum were significantly lower; serum adiponectin levels were significantly higher; and serum resistin levels were significantly lower in the 450 mg/(kg d) group than those of the model control group. There was no difference in serum C-reactive protein levels among the 3 SIF groups. CONCLUSION: Soy isoflavone may improve the insulin sensitivity by decreasing viscera fatty deposition and adjusting low-grade inflammatory molecules derived from white adipose tissues.

Animals↗
PubMed2006

[Analysis of loss of heterozygosity induced by vinblastine at tk locus in human lymphoblastoid cell line TK6].

OBJECTIVE: To establish TK gene mutation assay using human lymphoblastoid cell line TK6 and to study the genotoxic mechanism of Vinblastine (VBL). METHODS: TK6 cells were treated with Vinblastine at different concentrations (0.625 ng/mL, 1.250 ng/mL, 2.500 ng/mL and 5.000 ng/mL)for 24 h and TK gene mutation assay were experimented. Relative survival (RS%), relative suspension growth (RSG%), mutation frequency at tk locus and percentages of slow growth mutant (SC%) were detected and loss of heterozygosity (LOH) of mutants were analyzed. RESULTS: A decreased RS% and RSG% and an increased mutation frequency at tk locus were observed in a dose-dependent manner when the TK6 cells were treated with 0.625, 1.250, 2.500 and 5.000 ng/mL of Vinblastine respectively for 24 h. The result demenstrated that about 96.4% of Vinblastine-induced mutants were LOH. Among them, 39.3% were hemi-LOH and 57.1% were homo-LOH respectively. CONCLUSION: TK6 cell line can be used to detect the genotoxicity of Vinblastine and LOH was the major mutation events in Vinblastine-induced mutants.

Cell Line↗
PubMed2006

[Comparison of TK gene mutation assay in TK6 and TK6-E6 cell induced by vinblastin and colcemid].

OBJECTIVE: To compare TK gene mutation assay in human lymphoblastoid cell lines TK6 and TK6-E6 induced by vinblastin and colcemid. METHODS: Regular TK gene mutation assays were experimented to detect cytotoxicity and mutation frequency at tk locus after TK6 and TK6-E6 human lymphoblastoid cells were treated with vinblastin and colcemid for 24h. RESULTS: Relative survival (RS%) and Relative suspension growth (RSG%) of TK6 and TK6-E6 cells decreased when concentrations of vinblastin and colcemid increased. RS% and RSG% of TK6-E6 cells were higher than that of TK6 cells at the same doses. TK6 and TK6-E6 cells both were induced by vinblastin and colcemid. The TK6-E6's nature mutation frequency, induced mutation frequency and percentage of slow growth mutant (SG%) were lower than TK6' s at the same dose except group CCM 5.0ng/ml in MF and group CCM 0.625ng/ml in SC%. CONCLUSION: Both TK6 and TK6-E6 cell lines can be used in TK gene mutation assay, but TK6-E6 cell line was recommended to be used in the assay for its less quantity and doubling time.

Antineoplastic Agents, Phytogenic↗
PubMed2006

[Effects of soy isoflavone on gene expression of resistin in insulin-resistance rats].

OBJECTIVE: To assess the effects of soy isoflavone (SIF) on improving insulin reistance (IR) status in IR rats induced by high-fat and high-sugar diet and explore the possible mechanisms. METHODS: IR rats were randomly divided into four groups according to their insulin resistance indices (IRI). The rats in one model control group and three SIF groups were fed via gavage with water solutions containing SIF at doses of 0 mg/ kg x bw, 50 mg/kg x bw, 150 mg/kg x bw, and 450 mg/kg x bw, respectively. After one month, fasting glucose, fasting insulin, resistin in serum, and resistin mRNA in adipocyte around kidney were detected by enzymologic method, radioimmunoassay, enzyme linked immunosorbent assay, and real time RT-PCR, respectively. RESULTS: Comparison between the model control group and the other groups revealed that serum resistin and resistin mRNA expression levels were lower in the 450 mg/kg x bw group, that insulin and IRI levels were lower in the 150 mg/ kg x bw group and 450 mg/kg x bw group, and that no differences in plasma glucose levels existed among the 4 groups. A positive correlation between IRI and serum resistin level (r = 0.355, P < 0.05) was observed. CONCLUSION: These results suggest that soy isoflavone may down-regulate resistin mRNA expression, decrease serum resistin level and enhance insulin sensitivity.

Animals↗
PubMed2006

[The tk gene mutation analysis in WTK1 cell line by multiplex PCR].

OBJECTIVE: To explore the tk gene mutation spectrum in spontaneous and induced WTK1 mutants. METHODS: After exposure to methyl methanesulfonate (MMS), mitomycin (MMC) or sodiam azide (NaN3), spontaneously-arising and induced mutants of WTK1 cell line were selected. The spectrum and hotspot of tk gene mutation were analyzed by multiplex PCR. RESULTS: Three chemicals used in this study induced tk mutation frequency (MF) to increase significantly in a dose-dependent manner; most of the analyzed mutants had lost exon 4 and exon 5-7. CONCLUSION: Three chemicals have mutagenic effect on WTK1 cell line, and obvious hotspot exists in tk gene mutation.

Cells, Cultured↗
PubMed2006

[Effects of soy isoflavone on levels of low-grade inflammatory peptides in rats with insulin resistance].

OBJECTIVE: To explore the effects of soy isoflavone (SIF) on low-grade inflammation in rats with high-fat diet-induced insulin resistance (IR) and explore the mechanisms of SIF in improving insulin sensitivity. METHODS: The rats with high-fat diet-induced IR were randomly divided into one model control group and 3 SIF groups gavaged with SIF water solutions at the doses of 50, 150, and 450 mg/kg, respectively. One month after the treatment, fasting blood glucose (FBG), fasting insulin (FINS), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), C-reactive protein (CRP), resistin and adiponectin in the serum were detected by enzymatic method, radioimmunoassay, or enzyme-linked immunosorbent assay. RESULTS: In the 150 and 450 mg/kg SIF groups, fasting body-weights, visceral adipose tissue deposition, FINS, resistin, TNF-alpha in serum, and IR index were lowered in comparison with the model control group, and in 450 mg/kg SIF group, serum IL-6 level was obviously lowered, and adiponectin increased. No differences were found in serum C-reactive protein levels between the 3 SIF groups. CONCLUSION: Soy isoflavone may ameliorate insulin sensitivity by decreasing visceral adipose deposition and adjusting low-grade inflammatory molecules derived from white adipose tissue.

Adiponectin↗
PubMed2005

[Loss of heterozygosity induced by cyclophosphamide at tk locus in human lymphoblastoid cell line TK6].

OBJECTIVE: Human lymphoblastoid cell line TK6 was used to investigate TK gene mutation frequency and the loss of heterozygosity (LOH) induced by cyclophosphamide (CP). METHODS: Relative survival, mutation frequency at tk locus induced by CP (+S9) after 4 h treatment were detected. DNA isolated from mutants in the control culture and CP treatment group was analyzed for LOH. RESULTS: Exposure to CP for 4 h decreased relative survival, induced TK gene mutation in a dose-dependent manner. Doubling time of normally and slowly growing mutants was (14.6 +/- 1.74) h and (35.8 +/- 3.78) h respectively. The percentage of hemizygous LOH in CP-induced mutants (50%) was 2.4 times than that of the control (20.7%). CONCLUSION: Great damage to TK gene is the main cause of mutation induced by CPin TK6 cells.

Cell Line↗
PubMed2005

[Effects of zearalenone on proliferation and apoptosis in MCF-7 cells].

OBJECTIVE: To explore the effects of zearalenone (ZEA) on proliferation and apoptosis in estrogen-dependent human breast cancer MCF-7 cells and the likely underlying molecular mechanisms. METHODS: Cell viability was determined by MTT assay and cell cycle distribution by cytometry. Apoptosis was detected by Cell Death Detection ELISA and cytometry, respectively. The expressions of bax and bcl-2 were examined using multiple RT-PCR and Western-blot both at mRNA and protein level, respectively. RESULTS: The current study confirmed the previous studies that ZEA could stimulate proliferation in MCF-7 cells with inducing a profound increase in S phase and a modest increase in G(2)/M phase that was accompanied by a decrease in G(0)/G(1) phase. ZEA could inhibit apoptosis in MCF-7 cells following estrogen ablation at a range of concentrations of 2 nmol/L -96 nmol/L. Western blot and RT-PCR analysis revealed that the anti-apoptotic bcl-2 was upregulated at both protein and mRNA level, together with the downregulation of pro-apoptotic bax. CONCLUSION: ZEA should have possessed comparative estrogenic activity and could promote the progression of MCF-7 cells through the cell cycle by a decreasing in the G(0)/G(1) phase and by a significant increasing in S-phase. The pro-proliferative activity of ZEA was due to inhibition of apoptosis through regulation of bax/bcl-2 expression.

Apoptosis↗
PubMed2004

[TK locus mutation assay: comparison of L5178Y and TK6 cell lines].

OBJECTIVE: To compare the advantages and disadvantages of utilizing L5178Y and TK6 cell lines in the TK locus mutation assay. METHODS: The two cell lines were used for detecting and assessing the mutability of four chemicals (MMS, EMS, MMC and KCl); the microwell method of TK locus mutation assay was adopted. RESULTS: The two cell lines brought about similar results in the study. The tolerance of TK6 to all four chemicals was lower than that of L5178Y, and all the relative mutation indices of TK6 were higher than those of L5178Y. CONCLUSION: Each of the two cell lines has its own strong points; nevertheless, the authors recommend the applications of TK6 cell in the assay system since this cell line comes from human.

Animals↗
PubMed2004

[Study on the use of haemoglobin denaturation test as an alternative to Draize eye irritation test].

OBJECTIVE: To use haemoglobin denaturation test (HD test) as an alternative to Draize eye irritation test (Draize test). METHODS: Fourteen cosmetic ingredients were tested by HD test. The results were compared with two kinds of scores in Draize test, i.e. Maximum average Draize total score (MAS) and Score of 24 h after application (S24). RESULTS: The correlation coefficient between RDC50 and MAS and that between RDC50 and S24 were 0.926 and 0.921 respectively, while that between 1%lambdamax and MAS, and between 1%lambdamax and S24 were 0.881 and 0.791 respectively. The results showed that RDC50 had a higher correlation with Draize test than 1%lambdamax did, but in the use of RDC50 some information of data would be lost. On the other hand, 1%lambdamax, which had a greater correlation with corneal score in the three component scores of the Draize test, could be used for assessing water-insoluble chemicals. CONCLUSION: The results showed that HD test could be used as an effective alternative to Draize eye irritation test.

Animal Testing Alternatives↗
PubMed2004

[Experimental studies on male reproductive toxicity of bisphenol A in vitro and vivo].

OBJECTIVE: To explore the effects of Bisphenol A in adult rats and its possible mechanisms. METHODS: BPA (in corn oil) was administered orally to 9-week-old male Sprague-Dawley rats for 14 days (0, 1 and 5 g/kg bw), and incubated primary Sertoli cells from pubertal SD rats with 0, 10(-7), 10(-6), 10(-5), 10(-4) mol/L BPA. RESULTS: After oral administration, a significant decrease in right testis weight was observed in 5 g/kg dose group, but not in the 1 g/kg bw dose group. Germ cells were detached from basement membrane of seminiferous tubules and Sertoli cells in BPA-treated groups. Administration of BPA at 1 g/kg bw and 5 g/kg bw produced both nucleus pycnosis and vacuolized nucleus in germ cells and Sertoli cells. A marked loss in vimentin staining in Sertoli cells from testis of BPA-treated rats was detected. No change in levels of serum estradiol and testosterone was observed after two-week exposure to BPA. In Sertoli cell primary culture, BPA destroyed the cytoskeleton and cell-cell junctions, and elongated Sertoli cells. CONCLUSION: These results suggest that BPA may injure reproductive function of male rats by destroying the cytoskeleton and changing the form of Sertoli cells.

Animals↗
PubMed2004

[Sensitivity comparison of DNA damage and repair capacity in TK6 and WTK1 cells].

OBJECTIVE: Explore the mechanisms of DNA damage and repair capacity in TK6 and WTK1 cells that are derived from the same parental cell line WI-L2 (tk+/+) human diploid lymphoblastoid cells but are different in their p53 gene status. METHODS: The TK6 and WTK1 cells treated with H2O2 were detected by single cell gel electrophoresis. Then a comparison was made on the comet cell rate, comet cell tail length and p53 protein expression level between TK6 and WTK1. RESULTS: TK6 was more sensitive to DNA damage and its repair capacity was more quick and effective when compared with WTK1. Both TK6 and WTK1 cells showed effective post-damage repair capacity in incubation time of 0.5 h to 1 h. The background level of P53 protein in WTK1 was higher than that in TK6, but the level of P53 protein in H2O2-treated TK6 increased significantly higher than that in H2O2-treated WTK1. CONCLUSION: TK6 and WTK1 cells serve as a good biological experiment system for DNA damage sensitivity and repair capacity researches in the field of toxicology. TK6 is more sensitive to DNA damage, and it increases faster and higher than WTK1 after DNA being damaged. A possible explanation is that TK6 cell is of the p53 gene wild-type and WTK1 cell is of the mutant-type and they make different responses to the same chemical.

Cell Line↗
PubMed2003

[The effects of three plastic additives on the proliferation of MCF-7 cell].

OBJECTIVE: To explore the effect of environmental estrogens on the proliferation of breast cancer cell line MCF-7. METHODS: The tested compounds were n-4-nonyphenol, Bisphenol A and dibutylphthalate. Human estradiol-dependent MCF-7 breast cancer cells were grown in DMEM medium containing 10% bovine serum. Five days before the addition of the test compounds, the cells were washed by phosphate-buffered saline, and the medium was substituted with a phenol red-free DMEM medium containing 5% dextral charcoal-stripped FBS. The respective test compound was added in fresh medium and the control cell received only the vehicle (ethanol). The proliferation of MCF-7 was analyzed by the MTT assay, (3)H-TdR incorporation assay and flow cytometry. RESULTS: Compared with the ethanol control, the proliferation and DNA synthesis of the test cells treated with n-4-nonyphenol (8 x 10(-7) mol/L, 96 h), Bisphenol A (8 x 10(-7) mol/L, 96 h) or dibutylphthalate (32 x 10(-6) mol/L, 96 h) treatment was markedly enhanced in a time-dependent and dose-dependent manner. CONCLUSION: n-4-Nonyphenol, Bisphenol A and dibutylphthalate enhanced the proliferation of human breast cancer cell in vitro, which may demonstrate an estrogenic activity.

Benzhydryl Compounds↗
PubMed2003

[Effects of genistein and zearalenone on proliferation of PEO4].

OBJECTIVE: The objective of this study was to investigate the estrogenic activity of genistein and zearalenone through their effects on the proliferative capacity of human ovarian PEO4. METHODS: Estrogen receptor-positive PEO4 cell was grown in DMEM medium containing 10% bovine serum. Five days before the addition of the test compounds, the cells were washed in phosphate-buffered saline, and the medium was substituted with a phenol red-free DMEM medium containing 5% dextran charcoal-stripped FBS. The respective test compound was added in fresh medium and the control cell received only the vehicle (ethanol). Cell proliferation was detected respectively by MTT assay, (3)H-TdR incorporation and flow cytometry. RESULTS: Compared with vehicle control, 96 x 10(-6) mol/L GS significantly inhibited PEO4 cell proliferation and DNA synthesis as measured by MTT and (3)H-TdR incorporation after treatment for 24 h. Alao, 32 x 10(-6) mol/L GS could exert inhibition on PEO4 cell growth as time extension to 48 h. 32 x 10(-6) mol/L approximately 96 x 10(-6) mol/L GS induced G(2)/M arrest. At low dose (< 8 x 10(-6) mol/L=, GS promoted proliferation in PEO4 cells. ZEA enhanced proliferation, promoted DNA synthesis and increased the S phase population in PEO4 cells. CONCLUSIONS: Genistein possess estrogenic activity and zearalenone have anti-estrogenic activity. They play different effects on the proliferation of human ovarian cancer cell. Genistein enhanced the proliferation of PEO4. Zearalenone inhibited its the proliferation. These results implied that genistein and zearalenone elicit different signal-transduction channel.

Antineoplastic Agents↗
PubMed2003

[Effects of environmental estrogens on apoptosis induced by estrogen depletion in T47D cells].

OBJECTIVE: To explore the effects of environmental estrogens (n-4-noniphenol, NP; bisphenol, BisA; and dibutylphthalate, DBP) on apoptosis induced by estrogen depletion in breast cancer T47D cells. METHODS: Human T47D breast cancer cells were grown in DMEM medium containing 10% bovine serum. Four days before adding the test compounds, the cells were washed in phosphate-buffered saline, and the medium was substituted with a phenol red-free DMEM medium containing 5% dextral charcoal-stripped FBS. Respective test compound was added in fresh medium and the control cell received only the vehicle (ethanol). Apoptotic features in T47D cell were analyzed by light microscope that was commonly used to define apoptosis. DNA integrity of T47D cells was examined by agarose gel electrophoresis. Hypodiploid population was detected by flow cytometry. RESULTS: The typical characters of apoptosis in T47D cells were observed after estrogen deletion and then disappeared following exposure to T47D cells at 32 x 10(-7) mol/L Np and 32 x 10(-7) mol/L BisA respectively. Inhibition of apoptosis at 32 x 10(-6) mol/L DBP was not shown in our study. CONCLUSION: N-4-noniphenol and Bisphenol A could inhibit apoptosis induced by estrogen deletion in breast cancer T47D cells. This result suggests that these environmental estrogens might involve in signal transduction connected with apoptosis.

Apoptosis↗