ABSTRACT
Objective To determine the protective role of keratinocyte growth factor 2 (KGF-2) on dextran sodium sulfate (DSS)-induced murine colitis and investigate the mechanism of its effect on intestinal mucosal barrier.Methods A total of 36 male C57BL/c mice were divided into 4 groups:normal control group,DSS model group,model + KGF-2 (5 mg/kg) group and model + KGF-2 (10 mg/kg)group.Groups except the control were added 3.5 ％ DSS in drinking water.Disease activity index (DAD,weight change,colon length loss and histological score were detected to evaluate the protective effect of KGF-2 on colitis.Serum fluorescein isothiocyanate-dextran (FITC-D) permeability were assayed by multiscan spectrum.In order to explore the protective role of KGF-2 on murine intestinal mucosal barrier,ZO-1 and occludin protein concentration were detected by immunohistochemical staining and Western blot.Meanwhile,cytokines including TNF-α,IL-6,IL-10,TGF-1β,IFN-γ and IL-1β in colonictissue were detected by ELISA.Results Compared with DSS-induced colitis model group,10 mg/kg KGF-2 significantly reduced DAI (P =0.021 1),weight loss (P =0.017 6),colon length loss (4.956 ±0.2583 vs.6.289±0.215 7,P =0.001 1),histologicalscore (12.17±1.222 vs.7.000±0.6325,P =0.001 1),and FITC-D permeability (168.5 ± 27.01 vs.14.62 ± 1.812,P =0.004 7) and reversed the downregulation of tight junction (TJ) proteins (ZO-1:0.158 6 ± 0.010 51 vs.0.387 9 ± 0.028 64,P＜0.000 1;occluding:0.300 5 ± 0.026 56 vs.0.445 0 ± 0.056 62,P =0.043 4).Significant decrease of TNF-α (68.93 ± 3.379 vs.40.41 ± 1.576,P＜0.000 1) and increase of IL-6 (3 755 ± 309.8 vs.5 640 ± 418.0,P =0.004 7) and IL-10 (304.0 ± 21.47 vs.521.2 ± 49.40,P =0.002 4) levels were noted in the 10 mg/kg KGF-2 treated mice.The effect of the KGF-2 was dose-dependent.Conclusions KGF-2 could ameliorate DSS-induced colitis and it may be associated with the decrease of the damage of mucosal barrier structure and funcntion by preventing ZO-1 and occludin from downregulating.The protective effect of KGF-2 on intestinal barrier function may also be exerted by inhibition of TNF-α and stimulation of IL-6 and IL-10 secretion.
ABSTRACT
<p><b>OBJECTIVE</b>To establish a method for determination of the epichlorohydrin in drinking water by isotope dilution gas chromatography-mass spectrometry (GC-MS).</p><p><b>METHODS</b>The internal standard solution D5-epichlorohydrin was added in drinking water sample. The epichlorohydrin was firstly collected by active carbon, and the adsorbent was then centrifuged at 2739 × g for 10 min to remove water. Finally, the epichlorohydrin was desorbed by dipping the active carbon in 1.0 ml acetone for 1 h. The desorbed solution was tested by GC-MS and quantified with isotopic internal standards. The detection limit, precision and accuracy of the assay were evaluated. This method was adopted to detect the epichlorohydrin in drinking water for 25 batches in a city.</p><p><b>RESULTS</b>The determination method of epichlorohydrin represented a good linear relationship in the range of 0.0645-3.8700 µg/L, the linear regression equation was Y = 2.828X + 4.91 × 10(-2) (r > 0.999). When the epichlorohydrin concentration were 0.0806, 0.3230 and 3.2300 µg/L, the relative standard deviations (RSD) were 7.9%, 4.7% and 3.1%, respectively. The average recoveries were from 95.7% to 98.7%. The limit of detection (LOD) was 0.015 µg/L, limit of quantification (LOQ) was 0.052 µg/L. The content of epichlorohydrin in the 25 cases of drinking water was under the limit of detection.</p><p><b>CONCLUSION</b>The method is more simple than the national standard method, with high sensitivity, accuracy and good reproducibility, which is suitable for detection of the trace amounts of epichlorohydrin in drinking water.</p>