Green Tea Polyphenols Alleviate Autophagy Inhibition Induced by High Glucose in Endothelial Cells / 生物医学与环境科学（英文）

Bovine aortic endothelial cells (BAECs) were cultured with high glucose (33 mmol/L), 4 mg/L green tea polyphenols (GTPs) or 4 mg/L GTPs co-treatment with high glucose for 24 h in the presence or absence of Bafilomycin-A1 (BAF). We observed that high glucose increased the accumulation of LC3-II. Treatment with BAF did not further increase the accumulation of LC3-II. Results also showed an increased level of p62 and decreased Beclin-1. However, GTPs showed inversed trends of those proteins. Furthermore, GTPs co-treatment with high glucose decreased the level of LC3-II and a much higher accumulation of LC3-II was observed in the presence of BAF in comparison with high glucose alone. Results also showed a decreased p62 and increased Beclin-1. The results demonstrated that GTPs alleviated autophagy inhibition induced by high glucose, which may be involved in the endothelial protective effects of green tea against hyperglycemia.

Green Tea Polyphenols Attenuate High-Fat Diet-Induced Renal Oxidative Stress through SIRT3-Dependent Deacetylation / 生物医学与环境科学（英文）

Fifty male Wistar rats were fed a standard chow diet or a high-fat (HF) diet, and different concentrations of green tea polyphenols (GTPs) (0.8, 1.6, and 3.2 g/L) were administered in the drinking water. We found that the malondialdehyde (MDA) level in the HF diet group was significantly higher than that in the control (CON) group (P<0.05). Decreased peroxisome proliferator-activated receptor (PPAR)-α and sirtuin 3 (SIRT3) expression, and increased manganese superoxide dismutase (MnSOD) acetylation levels were also detected in the HF diet group (P<0.05). GTP treatment upregulated SIRT3 and PPARα expression, increased the pparα mRNA level, reduced the MnSOD acetylation level, and decreased MDA production in rats fed a HF diet (P<0.05). No significant differences in total renal MnSOD and PPAR-γ coactivator-1α (PGC1-α) expression were detected. The reduced oxidative stress detected in kidney tissues after GTP treatment was partly due to the higher SIRT3 expression, which was likely mediated by PPARα.

Determination of HS270, a new histone deacetylase inhibitor, in rat plasma by LC-MS/MS--application to a preclinical pharmacokinetic study.

A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been developed and fully validated to determine HS270, a new histone deacetylase (HDAC) inhibitor, in rat plasma using SAHA as the internal standard (IS). After a single step liquid-liquid extraction with acetoacetate, analytes were subjected to LC-MS/MS analysis using positive electro-spray ionization (ESI(+)) under selected reaction monitoring mode (SRM). The chromatographic separation was achieved on a Hypurity C(18) column (50 mm × 2.1 mm, i.d., 5 µm). The MS/MS detection was conducted by monitoring the fragmentation of m/z 392.3→100.1 for HS270, m/z 265.1→232.1 for IS. The method had a chromatographic running time of 2.5 min and linear calibration curves over the concentrations of 0.5-1000 ng/mL. The recovery of the method was 70.8-82.5% and the lower limit of quantification (LLOQ) was 0.5 ng/mL. The intra- and inter-batch precisions were less than 15% for all quality control samples at concentrations of 1.0, 100.0, and 750.0 ng/mL. The validated LC-MS/MS method has successfully applied to a HS270 pharmacokinetic study after oral doses of 25, 50, 100, 200 mg/kg, and i.v. dose of 5 mg/kg to rats.

Development and validation of a highly rapid and sensitive LC-MS/MS method for determination of SZ-685C, an investigational marine anticancer agent, in rat plasma--application to a pharmacokinetic study in rats.

A sensitive and rapid method was developed and validated for the quantitative analysis of the novel anticancer agent SZ-685C in rat plasma using high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) in negative ion mode in order to support the following pre-clinical and clinical studies. SZ-685C and the internal standard (IS, emodin) were extracted from rat plasma by a simple liquid-liquid extraction technique using ethyl acetate as extraction solvent. Chromatographic separation was performed on an Elite Hypersil BDS C18 column (100 mm × 2.1 mm i.d., 3 µm). Elution was carried out using methanol/acetonitrile/2mM ammonium formate (pH 4) (80:15:5 (v/v/v)) at a flow-rate of 0.3 mL/min with a run time of 2.5 min. This assay was linear over a concentration range of 50-10,000 ng/mL with a lower limit of quantification of 50 ng/mL. The intra- and inter-batch precision was less than 15% for all quality control samples at concentrations of 100, 1000 and 7500 ng/mL. These results indicate that the method was efficient with a short run time and acceptable accuracy, precision and sensitivity. This method was successfully applied to explore pharmacokinetics of SZ-685C in rats after oral and intravenous administration of this agent. The absolute bioavailability is about 54.8-66.8% and the t(1/2) is 5.7-9.2h, these results provide basic information for further comprehensive pre-clinical research.

Influence of alcohol on insulin sensitivity and insulin receptor substrate-1 mRNA expression in rat skeletal muscle / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the molecular mechanism of the effect of alcohol on insulin sensitivity.</p><p><b>METHODS</b>Four groups of Wistar rats were used, i.e. control (C) group, and low (L), moderate (M) and high (H) alcohol group. Alcohol doses of each group were 0, 0.6, 1.8 and 3.0 ml.(kg.bw)(-1).day(-1). Each group was comprised of 10 male and 10 female rats. Alcohol was given to rats by gastric intubation. Thirteen weeks later, serum was collected for testing of fasting plasma glucose and insulin. HOMA-IR index of each group were calculated. Total muscle RNA was extracted using Trizol Reagent (Promega). The expression level of IRS-1 mRNA in muscle was detected by RT-PCR.</p><p><b>RESULTS</b>In female rats, the fasting plasma glucose of group (8.36 +/- 0.57) mmol/L was higher and the fasting plasma insulin (15.25 +/- 3.32) was lower than those of group C (7.56 +/- 0.85, 20.80 +/- 3.25). The HOMA-IR of group L (1.775 3 +/- 0.138 1) was lower than that of group C (1.982 6 +/- 0.124 6) (P < 0.05), while IRS-1 mRNA (0.766 1 +/- 0.076 9) was up-regulated (P < 0.05); HOMA-IR of group M (2.202 2 +/- 0.271 0) was higher than that of group C (P < 0.01), while IRS-1 mRNA (0.501 8 +/- 0.049 2) was suppressed (P < 0.01); HOMA-IR of group H (1.850 1 +/- 0.162 8) was not significantly changed as compared with that of group C (1.982 6 +/- 0.124 6) (P > 0.05), while IRS-1 mRNA (0.418 1 +/- 0.049 1) was significantly suppressed (P < 0.01). In male rats, the fasting plasma glucose and insulin had the similar change as those of female rats. The HOMA-IR of group M (1.878 5 +/- 0.250 2) was lower than that of C group (2.147 3 +/- 0.330 8) (P < 0.05), IRS-1 mRNA was up-regulated (0.824 9 +/- 0.064 7) (P < 0.05).</p><p><b>CONCLUSIONS</b>The present study showed that low-to-moderate dose of alcohol could increase insulin sensitivity; while alcohol abuse could decrease insulin sensitivity. Sex difference in this effect was found. Changes of IRS-1 mRNA expression may be involved in the molecular mechanism of the effects of alcohol on insulin sensitivity.</p>

ROS-related enzyme expressions in endothelial cells regulated by tea polyphenols / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Elevation of reactive oxygen species (ROS), especially the level of superoxide is a key event in many forms of cardiovascular diseases. To study the mechanism of tea polyphenols against cardiovascular diseases, we observed the expressions of ROS-related enzymes in endothelial cells.</p><p><b>METHODS</b>Tea polyphenols were co-incubated with bovine carotid artery endothelial cells (BCAECs) in vitro and intracellular NADPH oxidase subunits p22phox and p67phox, SOD-1, and catalase protein were detected using Western blot method.</p><p><b>RESULTS</b>Tea polyphenols of 0.4 microg/mL and 4.0 microg/mL (from either green tea or black tea) down-regulated NADPH oxidase p22phox and p67phox expressions in a dose-negative manner (P < 0.05), and up-regulated the expressions of catalase (P < 0.05).</p><p><b>CONCLUSIONS</b>Tea polyphenols regulate the enzymes involved in ROS production and elimination in endothelial cells, and may be beneficial to the prevention of endothelial cell dysfunction and the development of cardiovascular diseases.</p>

[Comparison and analysis of the molecular character of breakpoints in introns of deletion hotspots of dystrophin gene].

OBJECTIVE: To study the exons deletion mechanisms for dystrophin gene, the molecular characters of breakpoints of junction fragments for deletion-type Duchenne muscular dystrophy (DMD) patients with 46 and 51 exons deletion were compared and analyzed. METHODS: Deletion-type DMD patients were detected by multiplex polymerase chain reaction(mPCR). The breakpoints of junction fragments with 46 and 51 exons deletions were cloned and sequenced respectively. RESULTS: Analysis of sequences of deletion-junction fragment of exon 46 showed that the 5'breakpoint was located in AT-rich region of intron 45 and the 3' breakpoint was in medium reiteration repeats (MER1) sequence. There existed 2 bp(ta) junction homology between two breakages. No small insertion, small deletion or point mutation was located near the junction point. Similarly, analysis of sequences of deletion-junction fragment of exon 51 showed that the 5 breakpoint was located in transposon-like human elements (THE1) of intron 50 and the 3' breakpoint was in L2 sequence. There existed 3 bp(cta) junction homology between two breakages. No small insertion, small deletion or point mutation was located near the junction point. By analyzing the secondary structure of junction fragments with 46 and 51 exons deletions, it was demonstrated that all breakpoints of junction fragments were located at the non-matching regions of single-strand hairpin. CONCLUSION: By comparing the junction fragments with 46 or 51 exons deletion, it was found that all of breakpoints were located in repeat sequences and the repeat sequences formed the single-strand hairpin which could make the introns instable and result in exon deletion.

Analytical solutions of simply supported magnetoelectroelastic circular plate under uniform loads.

In this paper, the axisymmetric general solutions of transversely isotropic magnetoelectroelastic media are expressed with four harmonic displacement functions at first. Then, based on the solutions, the analytical three-dimensional solutions are provided for a simply supported magnetoelectroelastic circular plate subjected to uniform loads. Finally, the example of circular plate is presented.