A matrix solid phase dispersion ( MSPD) method was developed for the simultaneous preparation of samples of 15 mycotoxin biomarkers including deoxynivalenol, aflatoxins and zearalenone from eggs, which were subsequently determined by liquid chromatography-electrospray ionization tandem mass spectrometry ( LC-ESI-MS/MS) under the multiple reaction monitoring ( MRM) mode. For the analysis, the samples were first mixed with C18 particles and loaded into an empty column, then 20 mL of acetonitrile/methanol (1:1, V/V) containing 1 mmol/L ammonium formate was used to elute the sample. The eluent was then dried with nitrogen flow and redissolved into the mobile phase. After filtration, samples were brought into vials and used for analysis. Different from other methods, no extra complicated purification and centrifugation steps were required in the procedure of MSPD. This method had good linearity in the range of 0. 2-100 ng/mL, with the correlation coefficient (r2) greater than 0. 9931. The limits of detection (LODs, S/N=3) and limits of quantification ( LOQs, S/N=3 ) of this method were 0. 05-2 μg/kg and 0. 2-4 μg/kg respectively. Comprehensive extraction recoveries of the 15 compounds ranged from 61% to 90%.

Objective: To study the influences of dihydrotestosterone (DHT) on the development of experimental autoimmune Graves disease (EAGD), and to observe the effect of DHT on cytokines in male BALB/c mice model. Methods: Male BALB/c mice aged 6-8 weeks were divided into 4 groups using random number table: (1) control group; (2) EAGD group; (3) placebo group; (4) DHT group. EAGD mice were induced with an adenovirus expressing the human thyroid stimulating hormone receptor antibody A-subunit (Ad-TSHR289). DHT (5mg) or a matching placebo were implanted one week before the first immunization. Thyroid hormones were detected with radioimmunoassay kit.. Cytokines [such as interferonγ (IFNγ), interleukin (IL)-4, IL-10, IL-9, and IL-17] producing cells from the spleen were detected using flow cytometry. Results: As expected Ad-TSHR289 treatment increased total thyroxine [EAGD group vs. control group: (117.76±32.69) nmol/L vs. (33.08±12.61) nmol/L, P<0.0001] and free thyroxine [EAGD group vs. control group: (15.01±11.55) pmol/L vs. (3.55±1.88) pmol/L, P<0.0001]. Treatment of DHT slightly lowered thyroid hormones [DHT group vs. placebo group: total thyroxine (114.80±44.27) nmol/L vs. (123.17±77.73) nmol/L; free thyroxine (13.48±6.01) pmol/L vs. (14.19±12.65) pmol/L], without significant difference (all P>0.05)]. However, the percentage of IL-10, but not IFN γ, IL-4, IL-9 and IL-17, secreted spleen cells increased in DHT group than in the placebo group [(7.11±3.29)% vs. (3.51±1.36)%, P<0.05]. Conclusion The effects of DHT on thyroid hormone are mild. It might play an immunomodulatory role in the male mouse Graves disease model by up-regulating the cytokine IL-10.