OBJECTIVETo further explore the carcinogenic activity of Sterigmatocystin (ST) and the possible synergistic carcinogenic effect of deoxynivalenol (DON) in NIH mice.

METHODSNIH mice were randomly divided into 6 groups, 30 in each. Five groups of mice were given by gastric intubation ST 3 microg/kg, ST 30 microg/kg, ST 3 microg/kg + DON 1.5 microg/kg, ST 30 microg/kg + DON 1.5 microg/kg and DON 1.5 microg/kg respectively, 3 times a week for 24 weeks. The remaining group of mice was given normal saline accordingly, serving as control. All mice were fed with HPLC-confirmed mycotoxin-free food, analysis. The mice were killed and pathologically examined at 58th and 74th weeks.

RESULTSNo pathological changes were found in the control group of mice. Adenocarcinoma of lung was observed in 25.0%, 41.7%, 62.5%, 69.2% and 37.5% of mice given ST 3 microg/kg, ST 30 microg/kg, ST 3 microg/kg + DON 1.5 microg/kg, ST 30 microg/kg + DON 1.5 microg/kg and DON 1.5 microg/kg, respectively. In addition, dysplasia of glandular stomach was detected in 50.0%, 58.3%, 37.5%, 53.8% and 25.0% of mice similarly treated.

CONCLUSIONOral administration of ST or DON can induce adenocarcinoma in lung and dysplasia of glandular stomach in NIH mice. There is synergistic carcinogenic effect when both ST and DON are given.

Adenocarcinoma ; chemically induced ; pathology ; Animals ; Female ; Gastric Mucosa ; pathology ; Lung Neoplasms ; chemically induced ; pathology ; Male ; Mice ; Precancerous Conditions ; chemically induced ; pathology ; Sterigmatocystin ; toxicity ; Trichothecenes ; toxicity

OBJECTIVETo study the effect of deoxynivalenol (DON), a mycotoxin produced by Fusarium graminearum, on action potentials of cultured cardiomyocytes and the possible protective effects of sodium selenite.

METHODSVentricular myocytes from neonatal Wistar rats were cultured, and the transmembrane action potentials were recorded with glass microelectrodes before and after addition of DON at different concentrations. The cultured cardiomyocytes were pretreated with 0.5 mg/L selenium (as sodium selenite) to observe the protective effects of selenium against the effects of DON.

RESULTSDON at concentrations of 50, 100 and 200 mg/L decreased the action potential parameters including action potential amplitude (APA), overshoot (OS), threshold potential (TP), maximum rate of depolarization (Vmax) and action potential discharging frequency (APF), and prolonged the action potential duration of 10%, 50% and 90% repolarization (APD(10), APD(50) and APD(90)). Some of the parameters, such as APA, Vmax, APD and APF, changed in a concentration-dependent manner. The cultured cardiomyocytes pretreated with 0.5 mg/L of selenium for about 16 h presented only slight changes in action potential parameters induced by 200 mg/L DON.

CONCLUSIONSDON inhibit the membrane action potentials of cardiomyocytes, suggesting DON may interfere with the transmembrane movement of Ca(2+) and K(+), and sodium selenite may decrease the toxic effect of DON on cultured cardiomyocytes.

Action Potentials ; drug effects ; Animals ; Animals, Newborn ; Antioxidants ; pharmacology ; Cells, Cultured ; Female ; Male ; Myocytes, Cardiac ; drug effects ; physiology ; Rats ; Rats, Wistar ; Selenium ; pharmacology ; Trichothecenes ; toxicity

OBJECTIVEThis study was to explore the cytotoxic effect and the related injury mechanism of deoxynivalenol (DON) on articular chondrocytes in human embryo.

METHODSArticular cartilage cells were isolated from knees of human embryo and cultured in DMEM/F12 medium. The cells of the 4th generation were divided into five groups and incubated with varying concentrations of DON as the followings: control group and group with DON of 0.1, 0.2, 0.4, 1.0 µg/ml. The effects of DON were observed 72 hours after incubation. Cell apoptosis was assayed by flow cytometry (FCM) with Annexin V-FITC/PI staining; MMP-13 and PGE2 were detected by ELISA kits; NO was measured by Griess assay with spectrophotometer. Inducible nitric oxide synthase (iNOS) and collagen II in cells were detected by FCM. The expression levels of iNOS, mRNA and collagen II mRNA were measured with RT-PCR.

RESULTSThe rates of cell apoptosis in DON groups were 6.78% - 19.05%, which were significantly higher than that in control (1.20%, F = 174.761, P < 0.05). The levels of NO in DON groups were 20.8 - 40.7 µmol/L, which were significantly higher than that in control (10.2 µmol/L, F = 91.966, P < 0.05). The levels of MMP-13 in DON groups were 0.25 - 0.56 µmol/L, which were significantly higher than that in control (0 µmol/L, F = 78.420, P < 0.05). The levels of PGE2 in DON groups were 3.2-20.6 µmol/L, which were significantly higher than that in control (11.6 µmol/L, F = 276.453, P < 0.05). The proportions of cells with positive iNOS in DON groups were 14.8% - 56.8% which were significantly higher than that in controls (7.1%, F = 214.614, P < 0.05). The proportions of cells with positive collagen II in groups with DON of 0.4 µg/ml and 1.0 µg/ml were 56.7% and 52.7%, which were significantly lower than that in control (62.2%, F = 5.134, P < 0.05). The relative absorbance values of iNOS mRNA in DON groups were 1.07 - 1.33, which were significantly higher than that in control (0.62, F = 8.358, P < 0.05). The levels of collagen II mRNA in groups with DON of 0.4 µg/ml and 1.0 µg/ml were 0.83 and 0.82, which were significantly lower than that in control (1.14, F = 7.887, P < 0.05).

CONCLUSIONDON could promote anabolism of NO in articular cartilage cells by which up-regulated the expression of PGE2 and MMP-13, which both promoted resolution of articular cartilage matrix such as collagen II. DON induced apoptosis in articular cartilage cells.

Cartilage, Articular ; cytology ; embryology ; Cells, Cultured ; Chondrocytes ; drug effects ; metabolism ; Dinoprostone ; metabolism ; Humans ; Matrix Metalloproteinase 13 ; metabolism ; Nitric Oxide ; biosynthesis ; Trichothecenes ; toxicity

This study aimed to discover potential biomarkers for dioxynivalenol (DON) intoxication. B6C3F1 male mice were rally exposed to 0.83, 2.5 and 7.5 mg/kg body weight (bw) DON for 8 days and the differential protein expressions in their blood plasma were determined by SELDI - Time-of-Flight/Mass Spectrometry (TOF/MS) and the immunoglobulins (Igs) G, A, M and E in the serum were investigated. 11.7 kDa protein was significantly highly expressed according to DON administration and this protein was purified by employing a methyl ceramic HyperD F column with using optimization buffer for adsorption and desorption. The purified protein was identified as a haptoglobin precursor by peptide mapping with using LC/Q-TOF/MS and MALDI-TOF/MS and this was confirmed by western blotting and ELISA. IgG and IgM in serum were decreased in a dose-dependent manner and IgA was decreased at 7.5 mg/kg bw DON administration, but the IgE level was not changed. To compare the expressions of haptoglobin and the Igs patterns between aflatoxin B1 (AFB1), zearalenone (ZEA) and DON intoxications, rats were orally administered with AFB1 1.0, ZEA 240 and DON 7.5 mg/kg bw for 8 days. Haptoglobin was increased only at DON 7.5 mg/kg bw, while it was slightly decreased at ZEA 240 mg/kg bw and it was not detected at all at AFB1 1.0 mg/kg bw. IgG and IgA were decreased by DON, but IgG, IgA, IgM and IgE were all increased by AFB1. No changes were observed by ZEA administration. These results show that plasma haptoglobin could be a diagnostic biomarker for DON intoxication when this is combined with examining the serum Igs.
Aflatoxin B1/toxicity ; Animals ; Blood Proteins/drug effects/*metabolism ; Enzyme-Linked Immunosorbent Assay ; Haptoglobins/drug effects/*metabolism ; Immunoglobulins/*blood/drug effects ; Male ; Mass Spectrometry ; Mice ; Mice, Inbred Strains ; Rats ; Rats, Wistar ; Trichothecenes/*toxicity ; Zearalenone/toxicity

Six 1-month-old piglets were intravenously injected with deoxynivalenol (DON) at the concentration of 1 mg/kg body weight, with three pigs each necropsied at 6 and 24 h post-injection (PI) for investigation of hepatotoxicity and immunotoxicity with special attention to apoptotic changes and cytokine mRNA expression. Histopathological examination of the DON-injected pigs revealed systemic apoptosis of lymphocytes in lymphoid tissues and hepatocytes. Apoptosis of lymphocytes and hepatocytes was confirmed by the TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method and immunohistochemical staining against single-stranded DNA and cleaved caspase-3. The number of TUNEL-positive cells in the thymus and Peyer's patches of the ileum was increased at 24 h PI compared to 6 h PI, but the peak was at 6 h PI in the liver. The mRNA expression of interleukin (IL)-1beta, IL-6, IL-18, and tumor necrosis factor (TNF)-alpha in the spleen, thymus and mesenteric lymph nodes were determined by semi-quantitative RT-PCR, and elevated expression of IL-1beta mRNA at 6 h PI and a decrease of IL-18 mRNA at 24 h PI were observed in the spleen. IL-1beta and IL-6 mRNA expressions increased significantly at 6 h PI in the thymus, but TNF-alpha decreased at 6 h PI in the mesenteric lymph nodes. These results show the apoptosis of hepatocytes suggesting the hepatotoxic potential of DON, in addition to an immunotoxic effect on the modulation of proinflammatory cytokine genes in lymphoid organs with extensive apoptosis of lymphocytes induced by acute exposure to DON in pigs.
Animals ; Apoptosis/*drug effects/immunology ; Cytokines/*biosynthesis/genetics ; Gene Expression Regulation/drug effects ; Histocytochemistry/veterinary ; In Situ Nick-End Labeling/veterinary ; Liver/*drug effects/immunology ; Lymphoid Tissue/*drug effects/immunology ; RNA, Messenger/*biosynthesis/genetics/immunology ; Reverse Transcriptase Polymerase Chain Reaction/veterinary ; Specific Pathogen-Free Organisms ; Swine/*immunology ; Trichothecenes/*toxicity