The aim of the present study was to investigate the mechanism of hyperoside protecting ECV-304 cells against tertbutyl hydroperoxide (TBHP)-induced injury. ECV-304 cell viability was measured by MTT assay. Cellular morphologic changes were observed using phase contrast microscopy. The genotoxic effects of TBHP and the protective ability of hyperoside were assessed by the Comet test. Lipid peroxidation was measured by HPLC method. The cellular redox status was determined from GSH/GSSG ratios. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. Western blot analysis was used to evaluate the levels of cytochrome c, p53, SIRT1, Bax and Bcl-2 expression. The results showed that 128 µmol/l hyperoside could effectively protect TBHP-treated ECV-304 cells from death, increase superoxide dismutase activity and significantly decrease malondialdehyde production. Hyperoside was effective in protecting against the induction of oxidized DNA bases and redox state alterations induced by TBHP. Furthermore, the release of proapoptotic cytochrome c from mitochondria was reduced by hyperoside, which increased the expression of antiapoptotic SIRT1 and inhibited the translocation of Bax from cytoplasm to mitochondria. Taken together, these results indicate that hyperoside is effective in protecting against the oxidative damage induced by TBHP. The mechanism of hyperoside protecting against ECV-304 cell apoptosis by TBHP is related with resuming mitochondrial function and regulating the expression of SIRT1 and Bcl-2 family members.

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This variation in practice indicates an opportunity exists to establish an evidence-based approach to QC that can be generalized across institutions.

Background: There are considerable demands to accurately measure estradiol (E 2 ) at low concentrations (<20 pg/mL) in postmenopausal women, men, pediatric patients, and patients receiving breast cancer treatment. Most current high-sensitivity LC-MS/MS E 2 methods require large sample volumes and involve complex sample preparations with dansyl chloride derivatization. Our study aims to develop a high-sensitivity, underivatized method using micro LC-MS/MS to reliably measure E 2 concentrations below 5 pg/mL by the use of low sample volume. Methods: A total of 290 μL of sample was mixed with internal standard (IS), E 2 -d4, and extracted with a mixture of hexane/ethyl acetate (90/10) (v/v). After extraction, sample was separated by Eksigent Ekspert™ micro LC 200 system with a flow rate of 35 μL/min in a total run time of 3.5 min and detected by SCIEX QTRAP 6500 mass spectrometer in a negative mode using transitions: 271/145 (quantifier) and 271/143 (qualifier). In this method, it was crucial to use HPLC columns with stability at a pH >10. Results:The validation study demonstrated broad linear ranges (3.0 -820.0 pg/mL) with r 2 > 0.999. Total precision was below 15% at all QC levels, and limit of quantification (LOQ) was 3.0 pg/mL. Our method showed good correlation with E 2 RIA (r 2 = 0.96, bias = −1.0 pg/mL) and modest correlation with E 2 Roche Cobas automated immunoassay (r 2 = 0.86, bias = 6.0 pg/mL). Conclusions:In conclusion, we developed and validated a routinely applicable micro LC-MS/MS method without derivatization for E 2 in blood samples with an LOQ of 3.0 pg/mL. IMPACT STATEMENTPatients under assessment of puberty delays, pubertal growth, gynecomastia, and efficiency of aromatase inhibitor (AI) treatment will benefit from the information presented here. Evidence presented on high-sensitivity LC-MS/MS assay for E 2 will allow better characterization of E 2 concentration in blood in the low measurement range. Knowledge in the field of LC-MS/MS method development for E 2 will be advanced by the information presented.

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