Mechanism of cleft palate in C57BL/6N mice induced by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin / 中华口腔医学杂志

Objective: To explore the molecular mechanism of cleft palate in mice induced by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD). Methods: The pregnant mice were randomly divided into TCDD-treated group (n=42) and control group (n=42). TCDD-treated group was given by gavage a single dose of TCDD (64 μg/kg) at 8: 00 AM on gestation day 10 (GD10) and the control group was given by gavage the isopyknic corn oil. At GD13-GD15, the fetal mice palate development was observed by HE staining. The mouse embryonic palatal mesenchymal cell proliferation was detected by 5-bromo-2-deoxyuridine (BrdU) immunofluorescence. The localization and expression of maternally expressed gene3 (MEG3) in mouse embryonic palatal mesenchymal cells was detected by situ hybridization and real-time PCR (RT-PCR). The key protein expressions of transforming growth factor-β (TGF-β)/Smad signaling pathway in mouse embryonic palatal mesenchyme were analyzed by Western blotting. The interaction of MEG3 and TGF-β receptor Ⅰ (TGF-βRⅠ) was examined by RNA binding protein immunoprecipitation (RIP). Results: At GD13 and GD14, compared with the control group, the ratio of BrdU-positive cells in the palatal mesenchyme of TCDD-treated fetuses decreased significantly (GD13, t=6.66, P=0.003; GD14, t=6.56, P=0.003). However, at GD15, the ratio of BrdU-positive cells was significantly increased (t=-5.98, P=0.004). MEG3 was mainly expressed in the nuclei of fetal mouse palatal mesenchymal cells, and the expression of MEG3 in TCDD group was significantly increased at GD13, GD14 and GD15(GD13, t=39.28, P=0.012; GD14, t=18.75, P=0.042; GD15, t=28.36, P=0.045). At GD14, TCDD decreased the levels of p-Smad2 and Smad4 in embryonic palate mesenchymal cells (p-Smad2, t=9.48, P=0.001;Smad4, t=63.10, P=0.001), whereas the expression of Smad7 was significantly increased at GD14 (t=30.77, P<0.001). The results of the RIP experiment showed that the amount of TGF-βRⅠ-bound MEG3 in mouse embryonic palatal mesenchymal cells in the TCDD group (23.940±1.301) was higher than that in the control group (8.537±1.523)(t=24.55, P<0.001). Conclusions: MEG3 is involved in the suppression of mouse embryonic palatal mesenchymal cell proliferation, functioning at least in part via interacting with the TGF-βRⅠ protein and thereby suppressing Smad signaling in the context of TCDD induced cleft palate.

Maternal Lead Exposure Induces Down-regulation of Hippocampal Insulin-degrading Enzyme and Nerve Growth Factor Expression in Mouse Pups / 生物医学与环境科学（英文）

Lead exposure is a known potential risk factor for neurodegenerative diseases such as Alzheimer's disease (AD). Exposure to lead during the critical phase of brain development has been linked with mental retardation and hypophrenia in later life. This study was aimed to investigate the effects of lead exposure of pregnant mice on the expressions of insulin-degrading enzyme (IDE) and nerve growth factor (NGF) in the hippocampus of their offspring. Blood samples were collected from the tail vein, and after anesthetizing the pups, the brain was excised on postnatal day 21. Lead concentrations were determined by graphite furnace atomic absorption spectrophotometry, and the expressions of IDE and NGF were determined by immunohistochemistry and Western blotting. Results showed that the reduction in IDE and NGF expression in the hippocampus of pups might be associated with impairment of learning and memory and dementia induced by maternal lead exposure during pregnancy and lactation.

Potential antiviral drug Pueraria crude extract and puerarin protect against ethanol-induced cytotoxicity in embryonic mouse hippocampal cultures / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To examine whether Chinese medical herb Pueraria crude extract (CP) and standard of pure puerarin (SP) possess the same neuroprotective effects during concomitant ethanol (EtOH) treatment.</p><p><b>METHODS</b>Hippocampus cultures were prepared from mice at gestational age of 18 day. Cell viability was measured by MTT assay. RT-PCR was employed to determine mRNA expression of superoxide dismutase (SOD).</p><p><b>RESULTS</b>As measured by MTT assay, supplementation with 15 mg/L CP or 10 mg/L SP afforded neuroprotection against all EtOH concentrations (50, 200 and 350 mmol/L, respectively) in embryonic hippocampal culture system. In addition, both 15 mg/L CP and 10 mg/L SP could decrease expression of SOD at mRNA level.</p><p><b>CONCLUSION</b>This study suggests that CP and SP could decrease oxidative stress induced by ethanol treatment by the decreased expression of SOD at mRNA level, and demonstrates antioxidative neuroprotective effect of CP and SP against developmental ethanol exposure in vitro.</p>

Effects of zearalenone on proliferation and apoptosis in MCF-7 cells / 中华预防医学杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Effects of environmental estrogens on apoptosis induced by estrogen depletion in T47D cells / 中华预防医学杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

The effects of three plastic additives on the proliferation of MCF-7 cell / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the effect of environmental estrogens on the proliferation of breast cancer cell line MCF-7.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>n-4-Nonyphenol, Bisphenol A and dibutylphthalate enhanced the proliferation of human breast cancer cell in vitro, which may demonstrate an estrogenic activity.</p>

Effects of genistein and zearalenone on proliferation of PEO4 / 中华预防医学杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Effect of zinc on bone metabolism in fetal mouse limb culture / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To determine the effects of zinc-deficiency and zinc-excess on bone metabolism.</p><p><b>METHODS</b>We developed the culture model of fetal mouse limbs (16th day) cultivated in self-made rotator with continuing flow of mixed gas for six days in vitro. The cultured limbs were examined by the techniques of 45Ca tracer and X-roentgenography.</p><p><b>RESULTS</b>The right limbs cultivated had longer bone length, higher bone density than the left limbs uncultivated from the same embryo; and histologically, the right limbs had active bone cell differentiation, proliferation, increased bone trabecula, clearly calcified cartilage matrix, and osteogenic tissue. Compared with the control group, the zinc-deficient group and zinc-excess (Zn2+ 120 mumol/L) group contained less osteocalcin (BGP) and 45Ca content, and lower AKP activity; whereas zinc-normal (Zn2+ 45 mumol/L and Zn2+ 70 mumol/L) groups contained more BGP and 45Ca contents, and higher AKP (alkaline phosphatase) activity.</p><p><b>CONCLUSION</b>Both zinc-deficiency and zinc-excess can alter bone growth and normal metabolism. The results indicate that the culture model of fetal mouse limbs (16th day) in vitro can be used as a research model of bone growth and development.</p>