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OBJECTIVE: To explore the effects of nano-silicon dioxide( SiO_2) on the survival and poly( ADP-ribose)polymerase-1( PARP-1) expression in human bronchial epithelial cells( 16 HBE cells). METHODS: i) The 16 HBE cells were treated with nano-SiO_2 at concentrations ranging from 0 to 100 mg/L for 24. 0 hours,and CCK-8 assay was used to examine cell viability. ii) The 16 HBE cells were divided into 6 groups: solvent control group( equal volume solvent treatment),micro-SiO_2 control group( treated with 20 mg/L micro-SiO_2),5,10,and 20 mg/L nano-SiO_2 groups( treated with the corresponding final dose of nano-SiO_2),and curcumin group. The curcumin group was given pretreatment with curcumin at a final concentration of 10 μmol/L for 2. 0 hours followed by treatment with a final concentration of 20 mg/L of nano-SiO_2. Cells in each group were harvested at time points of 4. 0,12. 0 and 24. 0 hours after treatment. The relative expression of PARP-1 mRNA and protein in 16 HBE cells was detected by quantitative real-time polymerase chain reaction and Western blotting respectively. RESULTS: i) The survival of 16 HBE cells decreased with increasing nano-SiO_2 treatment dose,showing a dose-effect relationship( P < 0. 01). ii) The expression of PARP-1 mRNA and protein in 16 HBE cells were dose-dependently decreased after nano-SiO_2 stimulation at the 12. 0 and 24. 0 hours time points( P < 0. 01). The expression of PARP-1 mRNA and protein in 5,10,and 20 mg/L nano-SiO_2 groups decreased at the above mentioned time points( P < 0. 05),compared with the solvent control group at the same time points. The expression of PARP-1 mRNA and protein in 20 mg/L nano-SiO_2 group was lower than that in the micro-SiO_2 control group at the same 12. 0 and 24. 0 hours time point( P < 0. 05). The above two indexes of cells were higher in curcumin group than that of 20 mg/L nano-SiO_2 group at the 12. 0 hours time point( P < 0. 05). CONCLUSION: Nano-SiO_2 stimulation can lead to decrease survival of 16 HBE cells in a dose-dependent manner and down-regulation of PARP-1 expression may be one of the mechanisms of proliferation and inhibition of 16 HBE cells induced by nano-SiO_2. Curcumin has certain protective effect on nano-SiO_2-induced 16 HBE cell injury.
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Objective To evaluate the effect of micronutrient selenium on atopic dermatitis-like skin lesions in mice.Methods After 4-week feed with forages lacking selenium,40 BALB/c mice were randomly and equally divided into 4 groups:selenium deficiency group fed with forages containing 0.01 mg/kg selenium for 4 weeks,normal selenium supplementation group fed with forages containing 0.25 mg/kg selenium for 4 weeks,excessive selenium supplementation group fed with forages containing 3.00 mg/kg selenium for 4 weeks,and control group fed with forages containing 0.25 mg/kg selenium for 4 weeks.Then,atopic dermatitis-like skin lesions were induced by dinitrochlorobenzene (DNCB) in the mice in sensitized groups,including the selenium deficiency group,normal selenium supplementation group and excessive selenium supplementation group.During sensitization,the severity of dermatitis in mice was monitored.Three weeks after the sensitization,the total plasma IgE level and inflammatory cell count in whole blood were measured.Skin tissues from the back of mice were subjected to histopathological examination and the selenium level was detected.Statistical analysis was carried out by one-way analysis of variance for comparisons of IgE levels and cell counts among different groups,as well as by Pearson correlation analysis and linear regression analysis for analyzing the correlation of various indices with the selenium level.Results Six days after the sensitization,the dermatitis severity scores were significantly higher in the sensitized groups than in the control group (On day 6,8,11,13,15 and 18 after the sensitization,F =44.897,76.622,114.866,33.352,28.605 and 11.271 respectively,all P ＜ 0.01).On day 11 after the sensitization,the dermatitis severity score was significantly higher in the excessive selenium supplementation group than in the selenium deficiency group and normal selenium supplementation group (both P ＜ 0.05).Compared with the control group,obvious pathological changes of dermatitis were observed in the sensitized mice,but there was no significant difference in the number of inflammatory cells in skin lesions among the 3 sensitized groups (all P ＞ 0.05).The inflammatory cell count in whole blood and total plasma IgE level in the sensitized mice increased along with the increase of dietary selenium levels,and the excessive selenium supplementation group showed higher total plasma IgE level ([167.17 ±8.49] μg/L) compared with the selenium deficiency group ([124.78 ± 5.32] μg/L,t =3.919,P ＜ 0.05),normal selenium supplementation group ([132.61 ± 4.71] μg/L,t =3.222,P ＜ 0.05) and control group ([109.13 ± 0.79] μg/L,t =6.485,P ＜ 0.05).The selenium level in the skin tissues of sensitized mice was positively linearly correlated with the total plasma IgE level (r =0.579,P ＜ 0.001),whole-blood white blood cell count (r =0.414,P ＜ 0.05),neutrophil count (r =0.439,P ＜ 0.05),lymphocyte count (r =0.417,P ＜ 0.05)and eosinophil count (r =0.505,P ＜ 0.01).Conclusion Different dietary selenium levels showed different effects on the severity of dermatitis in mice,and more severe dermatitis occurred in the excessive selenium supplementation group.
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Objective: To develop a method for determination of carnitine in serum using HPLC. Methods: The serum proteins were precipitated by acetonitrile and methanol. The organic extract was added derivatizing reagent and the solution was warmed to 60℃ for 2 hours. Atlantis C18 column (4.6 mm?150 mm,5?m)was used as stationary phase and methanol-ispropand-acetonitrile (35∶45∶20,v/v) as mobile phase; flow rate 1.0ml/min, UV wavelengh at 260nm. Results: The typical chromatogram from serum samples showed clear separation of carnitine. Y= 8490X-48200, r= 0.9999. Intra-day RSD was 1.6%-13.2%, and inter-day 1.8%-12.1%. The recovery rate was 98.5%. Conclusion: A method for determination of carnitine in serum using HPLC by adding derivatizing reagent was developed and it is simple, rapid and precise, and can be used for clinical test.