Genotoxicity evaluation of food additive titanium dioxide using a battery of standard in vivo tests.

The increasing use of titanium dioxide (TiO2) nanoparticles (NPs) has raised concern about the safety of food additive TiO2. TiO2 has been considered no longer safe by EFSA due to concerns over genotoxicity, however, there are conflicting opinions upon the safety of TiO2 as a food additive, and the number of in vivo genotoxicity studies conducted on food additive TiO2 was limited. In order to investigate the potential genotoxicity of food additive TiO2, we evaluated the genotoxicity of a commercial food additive TiO2 (average size of 135.54 ± 41.01 nm, range from 60.83 to 230.16 nm, NPs account for 30% by number) using a battery of standard in vivo tests, including mammalian erythrocyte micronucleus test, mammalian bone marrow chromosomal aberration test and in vivo mammalian alkaline comet test. After 15 days of consecutive intragastric administration at doses of 250, 500, and 1000 mg/kgBW, food additive TiO2 neither increased the frequencies of bone marrow micronuclei or chromosomal aberration in mice, nor induced DNA strand breakage in rat liver cells. These results indicate that under the condition of this study, food additive TiO2 does not have genotoxic potential although it contains a fraction of NPs.

Genotoxicity assessment of titanium dioxide nanoparticles using a standard battery of in vivo assays.

As one representative of nanometal oxides, titanium dioxide nanoparticles (TiO2-NPs) have been widely used, particularly in the food industry. The genotoxicity of TiO2-NPs has attracted great attention over the years. This study was undertaken to investigate the chromosome and DNA damage effects of TiO2-NPs (0, 50, 150, and 500 mg/kg BW) using rodent models. After a comprehensive characterization, we conducted a standard battery of in vivo genotoxicity tests, including the chromosomal aberration test (CA), micronucleus (MN) test, and the comet test. The results of all these tests were negative. There were no structural or numerical chromosomal abnormalities in mice bone marrow cells, no increase in the frequency of micronucleated polychromatic erythrocytes in mice bone marrow cells, and no elevation in % tail DNA in rat hepatocytes. This indicated that TiO2-NPs did not cause chromosomal damage or have a direct impact on DNA. These findings suggested that TiO2-NPs did not exhibit genotoxicity and provided valuable data for risk assessment purposes.

Toxicokinetics of zinc oxide nanoparticles and food grade bulk-sized zinc oxide in rats after oral dosages.

The increasing application of zinc oxide nanoparticles (ZnO NPs) in consumer products has raised concerns about the potential health risks in human. It is crucial to understand the toxicokinetic information of ZnO NPs, especially the differences between NPs and non-nano form material. This study investigated the toxicokinetic profile of ZnO NPs and food grade bulk-sized ZnO in rats after single or repeated oral dosages. For single oral administration of ZnO suspensions at 350 mg/kgbw, the Zn content in blood and tissues showed no elevation, the majority of ZnO particles were eliminated via feces within 48 h. For repeated oral exposure to ZnO suspensions at 350 mg/kgbw or ZnSO4 solution at 700 mg/kgbw for 90 days, elevated Zn levels were observed in liver, kidney, and bone in all three treatment groups, the Zn level recovered to normal level in liver and kidney, but not in bone, after a recovery period. ZnO NPs and bulk-sized ZnO showed similarity in toxicokinetics in rats, regardless of exposure duration or gender. ZnO particles shared a similar biodistribution profile with ZnSO4, and were likely to be absorbed mostly in ionic forms.

Safety assessment of phytase transgenic maize 11TPY050 in Sprague-Dawley rats by 90-day feeding study.

The present study aimed to evaluate the subchronic toxicity of feeding with phytase-transgenic maize line 11TPY050 in Sprague-Dawley (SD) rats. Rats (n = 10/sex/group) were fed with 12.5%, 25% or 50% (w/w) transgenic maize diet, 12.5%, 25% or 50% (w/w) non-transgenic isoline OSL940 maize diet, or 50% (w/w) commercially available Zhengdan958 maize diet for 90 days. Daily clinical observations and weekly measurements of body weights and food consumption were conducted. Blood samples were collected on day 46 and day 91 for hematology and clinical chemistry evaluations. At the end of the study, macroscopic and microscopic examinations were performed. No effects on body weight and food consumption were observed. The results of hematology, clinical chemistry, and absolute and relative organ weights in the transgenic maize group were comparable to those in the parental maize group. Several statistical differences were not dose-related and were not considered to be biologically significant. Furthermore, the terminal necropsy and histopathological examination showed no treatment-related changes among the groups. The results from the present 90-day feeding study of phytase-transgenic maize 11TPY050 indicated no unexpected adverse effects in SD rats. The phytase transgenic maize 11TPY050 has substantial equivalence with non-transgenic maize.

Safety assessment of phytase transgenic maize 11TPY001 by 90-day feeding study in rats.

11TPY001 is a transgenic maize that expresses the Aspergillus niger phyA2 gene which could significantly improve phosphorus bioavailability in monogastric animals. The present study was conducted to investigate the potential health effects of phytase transgenic maize 11TPY001 through a 90-day subchronic rodent feeding study. Maize grains from 11TPY001 or its parental counterpart maize OSL963 were incorporated into rodent diets at 12.5%, 25% and 50% concentrations by mass and administered to Sprague-Dawley rats (n = 10/sex/group) for 90 days. An additional control group of rats (n = 10/sex/group) were fed with common maize Zhengdan958 diets at 50% by mass. All formulated diets were nutritionally balanced. Body weights, food intake, hematology, serum chemistry, absolute and relative organ weights were measured, and gross as well as microscopic pathology were examined. Compared with rats fed OSL963 maize and the common maize diet groups, no adverse diet-related differences were observed in rats fed 11TPY001 maize diets with respect to clinical signs of toxicity, body weight/gain, food consumption/efficiency, hematology, clinical chemistry, organ weights, and gross and microscopic pathology. Under the conditions of this study, the results indicated that 11TPY001 did not cause any treatment related adverse effects in rats compared with its non-transgenic parental maize OSL963.

Safety evaluation of BPL9K-4 rice in a subchronic rodent feeding study.

In the present study, a new genetically modified rice producing phytase-lactoferricin fusion protein, BPL9K-4, was evaluated for safety in a 90-day rat feeding study. Rats were fed rodent diets formulated with BPL9K-4 rice, and were compared with rats fed diets formulated with its corresponding non-transgenic parental rice 9 K, commercially available non-transgenic rice Weiyou64, and a basal diet. BPL9K-4 and 9 K rice were formulated into diets at concentrations of 15%, 30% and 60%, and Weiyou64 common rice was added to diets at concentration of 60%. AIN93G diet was set as a basal-diet control. Diets of all groups were fed to rats (10/sex/group) for 90 days. Compared with rats in the 9 K, Weiyou64 and the basal-diet group, rats fed the BPL9K-4 diet did not show any treatment-related adverse effects on mortality, body weights, feed consumption, clinical chemistry, hematology, organ weights and gross and microscopic pathology. Under the conditions of this study, the genetically modified BPL9K-4 diets did not cause any toxicologically significant effects in rats following 90 days of dietary administration as compared with rats fed diets with the corresponding non-transgenic control diet and the basal-diet group. The results indicated that BPL9K-4 rice is as safe as its conventional comparators.

Toxic effects of atrazine on immune function in BALB/c mice.

This study was aimed to evaluate the toxic effects of different concentrations (23, 90, 360 mg/kg BW) of atrazine (ATZ) on immune function in BALB/c mice. Some parameters of general immunotoxicity, humoral immunity, cellular immunity, and non-specific immunity were tested. The studies showed that the high-dose ATZ induced a significant reduction in the final body weight of mice, the absolute and relative weights of spleen, the counts of white blood cell (WBC), lymphocyte (LYM), monocyte (MON), and the number of splenocyte. An increase in the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and cholesterol (CHO) in the high-dose ATZ group was observed. Pathological examination showed that the medium- and high-doses of ATZ caused atrophy and destruction of thymus, spleen, and hepatorenal toxicity. The serum interleukin-5(IL-5) level of mice and the number of plaque-forming cell (PFC) in spleen cells in the high-dose ATZ group decreased significantly while there was a significant increase of the serum immunoglobulin G (IgG) in the high-dose ATZ group when compared to the negative control group. In the high-dose ATZ group, the proliferation ability of T and B lymphocytes as well as the delayed-type hypersensitivity (DTH) response were significantly decreased. The low-dose ATZ (23 mg/kg BW) caused a significant decrease in the number of WBC and neutrophil (NEUT), as well as the proportion of polychromatic and normoblast. In summary, we thought the low-dose ATZ has a slight effect on the immune system; it can be preliminarily concluded that the lowest observed adverse effect level (LOAEL) of atrazine is 23 mg/kg BW in mice. Atrazine can cause immunotoxicity mainly through cellular and humoral immunity pathways.

Postweaning exposure to lanthanum alters neurological behavior during early adulthood in rats.

Lanthanum is a rare-earth element that has been used in various fields including medicine, agriculture and industry. Previously, in utero lanthanum exposure to dams was shown to alter neurobehavior and neurotransmitter levels in rat offspring; however, the effects of postweaning exposure to lanthanum on neurological behavior is still limited. The purpose of this study was to investigate the effects of postweaning exposure to lanthanum on neurological behavior during early adulthood in rats. Rats were orally exposed to 0, 2, 20, 60 mg/kg BW of lanthanum nitrate from postnatal day (PND) 24 to PND60. Our results indicated that lanthanum treatment significantly decreased body weight and food intake. Morris water maze test results showed that lanthanum significantly decreased escape latency and travel distance. Lanthanum treatment also significantly decreased grip strength, hindlimb strength, and running time & distance in motor activity test. Further results showed that lanthanum treatment significantly decreased plasma neurotransmitter levels of acetylcholine and norepinephrine as well as the number of neurons in the CA1 area of the hippocampus. These results suggest that postweaning exposure to lanthanum have adverse effects on neurobehaviors and the central nervous system, with no-observed-adverse-effect level at 2 mg/kg BW and benchmark dose lower confidence limit at 1.7 mg/kg BW.

Effects of in utero exposure to lanthanum on neurological behavior in rat offspring.

The increasing use of rare-earth elements in various fields has raised concern from public heath perspective regarding their accumulation in human body. Long-term exposure to lanthanum, one of the frequently used rare-earth elements in biomedicine and agriculture, has been previously shown to exert neurotoxicity during development in rats; however, the effects of short-term exposure to lanthanum during gestation on neurobehavioral development in rat offspring is still not clear. The purpose of this study is to investigate the effects of intrauterine exposure to lanthanum on neurobehavioral development in rat offspring. Dams were orally exposed to 0, 2, 20, & 60 mg/kg BW of lanthanum nitrate from gestation day 7 to day 16. Morris water maze test, hindlimb strength test, nociceptive perception test, and grip strength test were conducted during postnatal day 61 to 66 in rat offspring. Blood lanthanum concentration and plasma neurotransmitters were measured after sacrifice. The results showed that intrauterine exposure to lanthanum nitrate significantly impaired memory and spatial learning in Morris water maze test. Lanthanum treatment dose-dependently increased blood lanthanum concentration in dams and pups. Lanthanum treatment significantly decreased hindlimb and grip strength and increased delay time in nociceptive response. Plasma neurotransmitter results showed that lanthanum treatment significantly decreased the level of acetylcholine and serotonin while increased the level of glutamate in rat offspring. These results suggest that short-term in utero exposure to lanthanum has potential adverse effects on neurodevelopment in rat offspring.

Safety evaluation of mulberry leaf extract: Acute, subacute toxicity and genotoxicity studies.

Mulberry (Morus alba L.) leaves are of broad popular use for food or remedy purposes due to their bioactive properties, especially antidiabetic activity and antioxidative activity. The present study aimed to assess the toxicological profile of mulberry leaf extract (MLE), through acute, subacute toxicity and genotoxicity tests. Male and female rats received by gavage 15.0 g/kg bw of MLE in the acute toxicity test, and 0, 1.88, 3.75 and 7.50 g/kg bw/d of MLE for subacute toxicity test. In the acute toxicity study, no mortality or behavioral changes were observed, indicating the LD50 is higher than 15.0 g/kg bw. In the subacute toxicity test, no significant changes were observed in hematological, biochemical or histopathological parameters in the animals exposed. The no-observed-adverse-effect level in the subacute toxicity study was considered to be 7.50 g/kg bw/d, the highest dose tested. In the genotoxicity study, MLE showed no mutagenic activity in the Ames assay and no evidence of potential to induce chromosome aberrations or sperm abnormalities in mice exposed to 10 g/kg bw. Collectively, aqueous extract of mulberry leaves could be considered safe, and the results support the application of MLE as novel food ingredient or product.

Developmental immunotoxicity is not associated with the consumption of transgenic Bt rice TT51 in rats.

TT51 is a transgenic strain of Bt rice generated by fusing a synthetic CryAb/Ac gene into MingHui rice. In this study, rats from F0, F1, and F2 generations were fed a diet with 60% TT51 rice, MingHui rice, or nominal-origin rice. The study focused on developmental immunotoxicity in F1 and F2 offspring after long-term consumption of TT51. A wide range of immunological parameters was monitored in this two-generation study on reproductive toxicity. The experiments were performed on F1 and F2 offspring at postnatal days 21 and 42. No adverse clinical effects were observed in any of the experimental groups. In addition, histopathology observations and immunotoxicity tests, including hematological indicators, spleen lymphocyte subsets, natural killer cell activity, lymphoproliferative response, and plaque-forming cell assay, revealed no significant difference between the groups. These results indicated that developmental immunotoxicity was not associated with a diet of transgenic Bt rice TT51, compared to the parental MingHui rice.

[Regulation of α-tocopherol on NFκB and Nrf2 signaling pathway at early stage of N-nitrosomethylbenzylamine⁃induced human esophageal cell carcinogenesis].

OBJECTIVE: To investigate the regulation of α-Tocopherol on NFκB and Nrf2 signaling pathway at early stage of N-nitrosomethylbenzylamine (NMBzA)-induced human esophageal carcinogenesis. METHODS: Human normal esophageal HET-1A cells were treated with NMBzA at 50 µmol/L, 100 µmol/L for 24 h to intimate the initiation of esophageal carcinogenesis. For intervention groups, HET-1A cells were pre-treated with α-T at 25, 50, 100 µmol/L for 3 h and then co-treated with NMBzA (100 µmol/L) for 24 h. In comparison with HET-1A cells, human esophageal cancer EC109 cells were treated with α-T at corresponding concentrations. Cells treated with 0.1% DMSO were used as negative control. Immunofluorence staining was used for the determination of distribution and activation of NFκB p65 and Nrf2 in the cell. Real time PCR and Western blot were used to determine the expression levels of target genes including cyclinD1, KI67, proliferating cell nuclear antigen (PCNA), cyclo-oxygen-ase 2 (COX2), 5LOX, HO-1, NQO1 and GCLC. Flow cytometry was utilized to analyze the reactive oxygen species contents in the cells. RESULTS: As compared to the control group (1.00 ± 0.08), the expression of CyclinD1 (2.99 ± 0.15), KI67 (2.35 ± 0.38) and PCNA (2.46 ± 0.25) in HET-1A were all markedly increased by NMBzA treatment (F values were 97.23, 65.28, 34.62, P < 0.001). Also, the proportion of cells with nucleus translocation of NFκB p65 (71.0%, 98/138) or Nrf2 (36.3%, 49/135) were significantly increased (χ² values were 194.71, 133.72, P < 0.001), and the expression of COX2 (3.22 ± 0.17), 5LOX (2.87 ± 0.12) as well as HO-1 (1.87 ± 0.22), NQO1 (2.14 ± 0.08), GCLC (2.63 ± 0.41) at protein levels were elevated (F values were 72.35, 43.87, 69.23, 71.34, 85.79, P values were 0.013, 0.015, 0.010, 0.011, 0.002). Under the treatment with 50 µmol/L α-T, comparing with the control group(59.1%,65/110),the nuclear translocation of NFκB p65 (77.7%, 8/104) was clearly inhibited (χ² = 148.1, P < 0.001), and protein expression levels of COX2 (0.74 ± 0.19) and 5LOX (0.42 ± 0.13) were decreased (F values were 56.31, 73.25, P values were 0.003, 0.001). However, no changes on Nrf2 signaling pathway were observed; α-T showed little impact on NFκB or Nrf2 pathway in EC109 cells. CONCLUSIONS: At the early stage of NMBz-induced esophageal cancer, α-T could block the initiation of carcinogenesis through suppressing the activation of NFκB signaling pathway. It might be the major mechanism by which α-T is potentially chemopreventive to esophageal cancer. During the progression of esophageal cancer, the cells may acquire the adaptive functions to accommodate oxidative stress via activating Nrf2 pathway.

A subchronic oral toxicity study on pyrroloquinoline quinone (PQQ) disodium salt in rats.

A subchronic oral toxicity study on pyrroloquinoline quinone (PQQ) disodium salt was performed in rats. Sprague-Dawley rats were randomly divided into four groups (10 rats/sex/group) and administered with PQQ disodium salt at doses of 0 (control), 100, 200 and 400 mg/kg bw/day by gavage for 13 weeks. Daily clinical observations and weekly measurement of body weights and food consumption were conducted. Blood samples were obtained on day 46 and day 91 for measurement of hematology and serum biochemical parameters. Animals were euthanized for necropsy, selected organs were weighted and recorded. Histological examination was performed on all tissues from animals in the control and PQQ disodium salt treatment groups. No mortality or toxicologically significant changes in clinical signs, body weight, food consumption, necropsy findings or organ weights was observed. Differences between treated and control groups in some hematological and serum biochemical examinations and histopathological examination were not considered treatment-related. The no-observed-adverse-effect-level (NOAEL) of PQQ disodium salt in rats was considered to be 400 mg/kg bw/day for both sexes, the highest dose tested.

Immunotoxicological evaluation of corn genetically modified with Bacillus thuringiensis Cry1Ah gene by a 30-day feeding study in BALB/c mice.

This study was to investigate the immunotoxicological potential of corn genetically modified (GM) with Bacillus thuringiensis (Bt) Cry1Ah gene in BALB/c mice. Female BALB/c mice were randomly assigned to one of the four groups: the negative control group, the parental corn group, the GM corn group and the positive control group with 10 mice per group. Mice in the GM corn group and the parental corn group were fed with diets containing 70% corresponding corn for 30 days. Mice in the negative control group and the positive control group were fed with AIN93G diet, administered with saline or 200 mg/kg of cyclophosphamide (CY) via intraperitoneal injection 24 h before the termination of the study, respectively. At the end of the study, the immunotoxicological effects of the GM corn were evaluated through immunopathology parameters including body and organ weights, hematology and clinical chemistry parameters, histological examination, peripheral blood lymphocytes phenotype; humoral immunity including antibody plaque-forming cell, serum immunoglobulin, cytokine and half hemolysis value; cellular immunity such as mitogen-induced splenocyte proliferation, cytotoxic T-lymphocyte reaction, delayed-type hypersensitivity reaction; non-specific immunity including phagocytic activities of phagocytes, natural killer cell activity. A single dose of cyclophosphamide (200 mg/kg bw) was found to have significant adverse effects on immunopathology, cellular immunity, and humoral immunity in mice. The corn genetically modified with Bt Cry1Ah gene is considered consistent with the parental corn in terms of immunopathology, humoral immunity, cellular immunity and non-specific immunity. No adverse immunotoxicological effects of GM corn with Bt Cry1Ah gene were found when feeding mice for 30 days.

[Study on animal model of testing food allergenicity in BN rat].

OBJECTIVE: To establish a BN rat model for testing food allergenicity. METHODS: BN rats of both sex and aged 4 and 8 weeks were exposed to different doses of ovalbumin (OVA) (1.00 mg, 0.10 mg and 0.01 mg) by intraperitoneal injection on the 1st, 5th and 10th day of the study and observed for 35 days. Blood samples were taken on the 28th and 35th day of the study from orbital plexus and serum specific IgE (OVA sIgE) were determined by ELISA. RESULTS: Compared with the control group, the concentrations of OVA sIgE of 8-week female BN rats on the 28th and 35th day were significantly increased when 1.00 mg and 0.10 mg OVA was applied (P < 0.05). The concentrations of OVA sIgE of 8-week male BN rats on the 28th day were significantly higher than that in the control group when 0.10 mg and 0.01 mg OVA was applied (P < 0.05). And the concentrations of OVA sIgE of 8-week male BN rats on the 35th day were significantly higher than that in the control group when 1.00 mg OVA was applied (P < 0.05). The concentrations of OVA sIgE of 4-week male BN rats on the 35th day were significantly higher than the control group when 1.00 mg OVA was applied (P < 0.05). CONCLUSION: Female rats were more sensitive than male rats to different doses of OVA administered intraperitoneally; 8-week rats were more sensitive than 4-week rats; the better dose of OVA for sensitizing BN rats was 0.10 mg or 1.00 mg. Therefore, an ideally sensitized animal model could be established by administering 8-week female BN rats with 0.10 mg or 1.00 mg OVA intraperitoneally in 35 days later.

[Immunotoxicologic assessment of genetically modified drought-resistant wheat T349 with GmDREB1].

OBJECTIVE: To assess the immunotoxicologic effects of genetically modified drought resistant wheat T349 with GmDREB1 gene. METHODS: A total of 250 female BALB/c mice (6-8 week-old, weight 18-22 g) were divided into five large groups (50 mice for each large group) by body weight randomly. In each large group, the mice were divided into five groups (10 mice for each group) by body weight randomly, which were set as negative control group, common wheat group, parental wheat group, genetically modified wheat group and cyclophosphamide positive control group, respectively. Mice in negative control and positive control group were fed with feedstuff AIN-93G, mice in common wheat group, non-genetically modified parental wheat group and genetically modified wheat group were fed with feedstuffs added corresponding wheat (proportion up to 76%) for 30 days, then body weight, organ coefficient of spleen and thymus, peripheral blood lymphocytes phenotyping, serum cytokine, serum immunoglobulin, antibody plaque-forming cell (PFC), serum 50% hemolytic value (HC50), mitogen-induced splenocyte proliferation, delayed-type hypersensitivity (DTH) reaction and phagocytic activities of phagocytes were detected respectively. RESULTS: After 30 days raise, among negative control group, common wheat group, non-genetically modified parental wheat group, genetically modified wheat group and cyclophosphamide positive control group, mice body weight were (21.0±0.3), (20.4±0.7), (21.1±1.0), (21.1±1.0), (19.4±1.0) g, respectively (F=7.47, P<0.01); organ coefficient of spleen were (0.407±0.047)%, (0.390±0.028)%, (0.402±0.042)%, (0.421±0.041)%, (0.304±0.048)%, respectively (F=12.41, P<0.01); organ coefficient of thymus were (0.234±0.032)%, (0.246±0.028)%, (0.249±0.040)%, (0.234±0.034)%, (0.185±0.039)%, respectively (F=5.58, P<0.01); the percentage of T cell in peripheral blood were (70.43±4.44)%, (68.33±5.37)%, (73.04±2.68)%, (74.42±2.86)%, (90.42±1.66)%, respectively (F=57.51, P<0.01); the percentage of B cell were (13.89±3.19)%, (15.34±4.84)%, (13.06±4.22)%, (12.93±2.36)%, (3.01±0.96)%, respectively (F=12.79, P<0.01); the percentage of Th cell were (55.87±3.80)%, (55.24±4.60)%, (57.92±3.70)%, (59.57±2.54)%, (77.37±2.31)%, respectively (F=68.58, P<0.01);the Th/Ts ratio were 4.16±0.29, 4.73±0.96, 4.19±0.78, 4.52±0.40, 6.34±0.73, respectively (F=17.57, P<0.01);the serum IgG were (1046.38±210.67), (1065.49±297.22), (1517.73±299.52), (1576.67±241.92), (1155.88±167.05) µg/ml, respectively (F=10.53, P<0.01); the serum IgM were (333.83±18.97), (327.73±27.72), (367.47±27.18), (363.42±46.14), (278.71±24.42) µg/ml, respectively (F=12.11, P<0.01); the serum IgA were (51.69±10.10), (42.40 ± 8.35), (32.11±4.22), (37.12±4.90), (41.45±8.89) µg/ml, respectively (F=8.25, P<0.01); the PFC were (29.2±14.6), (28.0±20.0), (34.8±30.9), (33.2±25.1), (4.8±5.3) per 10(6) splenocyte, respectively (F=3.33, P<0.05); the HC50 were 82.3±6.5, 79.7±4.6, 75.8±4.1, 74.9±3.6, 70.8±2.1, respectively (F=9.99, P<0.01);the LPS-induced splenocyte proliferation were 0.21±0.10, 0.21±0.14, 0.26±0.12, 0.25±0.14, 0.07±0.06, respectively (F=4.18, P<0.05). CONCLUSION: The genetically modified drought-resistant wheat T349 was substantially equivalent to parental wheat in the effects on immune organs and immunologic functions of mice, and it didn't show immunotoxicity.

Simultaneous determination of thiamphenicol, florfenicol and florfenicol amine in swine muscle by liquid chromatography-tandem mass spectrometry with immunoaffinity chromatography clean-up.

A rapid and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method to quantify thiamphenicol (TAP), florfenicol (FF), and florfenicol amine (FFA) in swine muscle is described. An immunoaffinity chromatography (IAC) column based on polyclonal antibodies and protein A-sepharose CL 4B was used to clean-up extracted samples. IAC optimized conditions were found that allowed the IAC to be reused for selective binding of TAP, FF, and FFA. The dynamic column capacity was more than 512ng/mL of gel after being used for 15 cycles. From fortified swine muscle samples at levels of 0.4-50ng/g, the average recoveries were 85.2-98.9% with intra- and inter-day variations less than 9.8% and 12.4%, respectively. The limit of quantitation ranged from 0.4 to 4.0microg/kg.

[Determination of 5 polyether antibiotics in chicken tissues by liquid chromatography-electrospray ionization tandem mass spectrometry].

A liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) method for the determination of 5 polyether antibiotics (lasalocid, salinomycin, monensin, narasin and maduramicin) in chicken tissues was developed. The polyether antibiotics were extracted from chicken tissues with methanol. The extract was evaporated to dry, and redissolved in hexane, then cleaned up on a Sep-Pak Silica solid-phase extraction cartridge. The target drugs were eluted with 6 mL methylene chloride-methanol (90:10, v/v), and the eluate was collected and dried under a gentle stream of nitrogen gas, then the residue was dissolved with 1 mL acetonitrile (containing 0.1% formic acid) and analyzed by LC-MS/MS. The LC separation was performed on a Symmetry Shield reversed phase C18 bonded silica column with acetonitrile (containing 0.1% formic acid)-0.1% formic acid (97:3, v/v) as mobile phase. The quantification was carried out by positive electrospray ionization and multiple reaction monitoring (MRM) mode. The validation was carried out on spiked chicken muscle (spiked at 0.1 -1500 microg/kg) and chicken liver (spiked at 0.2-4500 microg/kg), the average recoveries of target drugs ranged from 71.6%-99.1% with intra-day relative standard deviations (RSDs) of 3.2%-10.7% and inter-day RSDs of 4.6%-14.7%. The limits of quantification (LOQs) in chicken muscle and liver were 0.1-1.0 kg/kg. The results demonstrated that the sensitivity, accuracy and precision of this method meet the requirements of veterinary drug residue analysis. The method is applicable to detect 5 polyether antibiotics in chicken muscle and liver.