Research Progress on the Toxic Antagonism of Selenium Against Mycotoxins

Animal feed is prone to becoming infected with molds during production and storage, resulting in secondary metabolite mycotoxins, such as aflatoxin B₁ (AFB₁), T-2 toxins, deoxynivalenol (DON), and ochratoxin A (OTA), which are harmful to humans and animals. Selenium is an essential trace element for humans and animals, and it is also an effective antioxidant. Many studies have shown that selenium can reduce the damage caused by mycotoxins in animals. This article reviews the current literature on the antagonistic effects of selenium on AFB₁, T-2, DON, and OTA toxicity.

Ageratina adenophora causes spleen toxicity by inducing oxidative stress and pyroptosis in mice

Ageratina adenophora is an invasive weed with potent toxicological effects on livestock. Oxidative stress and pyroptosis play a pivotal role in regulating animal or human health and disease. The object of this study was to determine the mechanism underlying splenic toxicity induced by A. adenophora in a mouse model. Ageratina adenophora significantly increased the levels of reactive oxygen species and malondialdehyde, but decreased the antioxidants like catalase, superoxide dismutase, glutathione and glutathione peroxidase. In addition, the activity of the antioxidant enzymes was also decreased upon A. adenophora treatment. The induction of the pyroptosis pathway was evaluated in terms of the expression levels of Nod-like receptor protein 3, nuclear factor-κB, caspase-1, gasdermin-D and interleukin-1β, all of which were significantly elevated by A. adenophora. These findings suggest that A. adenophora impairs spleen function in mice through oxidative stress damage and pyroptosis.

The Molecular Mechanisms of Protective Role of Se on the G0/G1 Phase Arrest Caused by AFB1 in Broiler's Thymocytes

This research was designed to explore the protective effects of sodium selenite on G₀/G₁ phase arrest induced by AFB₁ in thymocytes of broilers. Two hundred eighty-eight Cobb broilers were divided into control group, + Se group (0.4 mg/kg Se), AFB₁ group (0.6 mg/kg AFB₁), and AFB₁ + Se group (0.6 mg/kg AFB₁ + 0.4 mg/kg Se). The results revealed that 0.4 mg/kg Se supplement in diets could improve the AFB₁-induced histological lesions in the thymus consisting of the more vacuoles and nuclear debris in thymic cortical area. The results of flow cytometric detect showed that 0.4 mg/kg Se relieved the G₀/G₁ phase arrest caused by AFB₁ in thymocytes. The results of transcription levels of ATM, p53, p21, p27, p15, p16, CyclinD₁, CyclinE, Cdk6, Cdk2, and PCNA genes by qRT-PC, and protein expression level of PCNA by immunohistochemistry demonstrated that 0.4 mg/kg Se could reduce the adverse effects of AFB₁ on these parameters. In conclusion, Se could relieve AFB₁-induced G₀/G₁ phase arrest by p15 (or p16)-CyclinD₁/Cdk6, ATM-p53-p21-CyclinE/Cdk2, p27-CyclinE/Cdk2 pathways.

The role of different SIRT1-mediated signaling pathways in toxic injury

Common environmental pollutants and drugs encountered in everyday life can cause toxic damage to the body through oxidative stress, inflammatory stimulation, induction of apoptosis, and inhibition of energy metabolism. Silent information regulator 1 (SIRT1), a nicotinamide adenine dinucleotide-dependent deacetylase, is a member of the evolutionarily highly conserved Sir2 (silent information regulator 2) superprotein family, which is located in the nucleus and cytoplasm. It can deacetylate protein substrates in various signal transduction pathways to regulate gene expression, cell apoptosis and senescence, participate in the process of neuroprotection, energy metabolism, inflammation and the oxidative stress response in living organisms, and plays an important role in toxic damage caused by toxicants and in the process of SIRT1 activator/inhibitor antagonized toxic damage. This review summarizes the role that SIRT1 plays in toxic damage caused by toxicants via its interactions with protein substrates in certain signaling pathways.

Identification, genotyping, and pathogenicity of Trichosporon spp. Isolated from Giant pandas (Ailuropoda melanoleuca)

Background

Trichosporon is the dominant genus of epidermal fungi in giant pandas (Ailuropoda melanoleuca) and causes local and deep infections. To provide the information needed for the diagnosis and treatment of trichosporosis in giant pandas, the sequence of ITS, D1/D2, and IGS1 loci in 29 isolates of Trichosporon spp. which were isolated from the body surface of giant pandas were combination to investigate interspecies identification and genotype. Morphological development was examined via slide culture. Additionally, mice were infected by skin inunction, intraperitoneal injection, and subcutaneous injection for evaluation of pathogenicity.

Results

The twenty-nine isolates of Trichosporon spp. were identified as 11 species, and Trichosporon jirovecii and T. asteroides were the commonest species. Four strains of T. laibachii and one strain of T. moniliiforme were found to be of novel genotypes, and T. jirovecii was identified to be genotype 1. T. asteroides had the same genotype which involved in disseminated trichosporosis. The morphological development processes of the Trichosporon spp. were clearly different, especially in the processes of single-spore development. Pathogenicity studies showed that 7 species damaged the liver and skin in mice, and their pathogenicity was stronger than other 4 species. T. asteroides had the strongest pathogenicity and might provoke invasive infection. The pathological characteristics of liver and skin infections caused by different Trichosporon spp. were similar.

Conclusions

Multiple species of Trichosporon were identified on the skin surface of giant panda, which varied in morphological development and pathogenicity. Combination of ITS, D1/D2, and IGS1 loci analysis, and morphological development process can effectively identify the genotype of Trichosporon spp.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1486-7) contains supplementary material, which is available to authorized users.

Sodium Fluoride (NaF) Induces Inflammatory Responses Via Activating MAPKs/NF-κB Signaling Pathway and Reducing Anti-inflammatory Cytokine Expression in the Mouse Liver

At present, no reports are focused on fluoride-induced hepatic inflammatory responses in human beings and animals. This study aimed to investigate the mRNA and protein levels of inflammatory cytokines and signaling molecules for evaluating the effect of different doses (0, 12, 24, and 48 mg/kg) of sodium fluoride (NaF) on inflammatory reaction in the mouse liver by using methods of experimental pathology, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot analysis. We found that NaF in excess of 12 mg/kg caused the hepatic inflammatory responses, and the results showed that NaF activated the mitogen-activated protein kinases (MAPKs) signaling pathway by markedly increasing (p < 0.01 or p < 0.05) mRNA and protein levels of apoptosis signal-regulating kinase 1 (ASK1), mitogen-activated protein kinase kinases 1/2 (MEK1/2), extracellular signal-regulated protein kinases 1/2 (Erk1/2), mitogen-activated protein kinase kinases 4/7 (MEK4/7), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38) and mitogen-activated protein kinase kinases 3/6 (MEK3/6), and the nuclear factor-kappa B (NF-κB) signaling pathway by increasing (p < 0.01 or p < 0.05) the production of NF-κB and inhibitor of nuclear factor kappa-B kinase subunit beta (IKK-β) and reducing (p < 0.01 or p < 0.05) the production of the inhibitory kappa B (IκB). Thus, NaF that caused the hepatic inflammatory responses was characterized by increasing (p < 0.01 or p < 0.05) the production of pro-inflammatory mediators such as interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemotactic protein 1 (MCP-1), and cyclooxygenase-2 (COX-2) via the activation of MAPKs and NF-κB pathways, and by significantly inhibiting (p < 0.01 or p < 0.05) the production of anti-inflammatory mediators including interleukin-4 (IL-4) and transforming growth factor beta (TGF-β).

[Chemical separation product of Ageratina adenophora essential oil (AAEO) inhibits the inflammation of RAW264.7 cells induced by lipopolysaccharide]

Objective To investigate the anti-inflammatory activity of Ageratina adenophora essential oil (AAEO-CP) and its effects on the expression of Toll-like receptor 4 (TLR4) protein in lipopolysaccharide (LPS)-induced RAW264.7 cells. Methods RAW264.7 cells were divided into control group, LPS group, and LPS combined with AAEO-CP group. The cytotoxicity of AAEO-CP was detected by CCK-8 assay. The mRNA and protein expression of interleukin-6 (IL-6) and IL-10 were detected by real-time PCR and ELISA, respectively, and the protein expression of TLR4 in RAW264.7 cells was measured by Western blotting. Results AAEO-CP below 20 mg/mL was not cytotoxic to RAW264.7 cells. LPS increased the protein expression of TLR4, also increased the protein and mRNA expression of IL-6, but decrease the protein and mRNA expression of IL-10 in RAW264.7 cells. And all of the above results were reversed by AAEO-CP. Conclusion AAEO-CP can play the anti-inflammatory effects by increasing the expression of IL-10 protein and decreasing the expression of IL-6 protein, and inhibiting TLR4 protein in LPS-induced RAW264.7 cells.

Selenium Rescues Aflatoxin B1-Inhibited T Cell Subsets and Cytokine Levels in Cecal Tonsil of Chickens

Cecal tonsil is the largest peripheral lymphoid organ of the gut-associated lymphoid tissue executing immune function. To evaluate the protective effect of selenium (Se) on the cecal tonsil of chicken exposed to aflatoxin B₁ (AFB₁), 144 1-day-old healthy Cobb chickens were randomly divided into four groups, and fed with basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se supplement (+Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se supplement (AFB₁ + Se group) for 21 days, respectively. The results showed that AFB₁ significantly decreased the percentages of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺ T cells, and the CD4⁺/CD8⁺ ratio, and suppressed the expressions of IL-2, IL-4, TNF-α, and IFN-γ mRNA in the cecal tonsil. However, Selenium (Se) supplied in the diets restored the percentages of T cell subsets, the CD4⁺/CD8⁺ ratio, and mRNA expressions of cytokines in the AFB₁ group to be close to those in the control group, and did not exhibit obvious toxicity to the cecal tonsil. These results indicated that Se exerted protective effect against AFB₁ on the functions of cecal tonsil, and also partially uncovered a new role of Se that could protect cecal tonsil of chickens from immunotoxicity of AFB₁.

Resistin up-regulates LPL expression through the PPARγ-dependent PI3K/AKT signaling pathway impacting lipid accumulation in RAW264.7 macrophages

Resistin is a cysteine-rich cytokine, which has been indicated as a mediator of insulin resistance and inflammation. Previous studies demonstrated that lipoprotein lipase (LPL) was an important enzyme that could mediate lipid accumulation in macrophages. Additionally, the intracellular molecules phosphatidylinositol 3-kinase (PI3K)/serine-threonine protein kinase (AKT)/peroxisome proliferator-activated receptor (PPARγ) were supposed to be involved in the lipid accumulation process in cells. However, it remains unclear whether resistin was correlated with the dysregulation of lipid metabolism in macrophages. The present study investigated that resistin could up-regulate the expression of LPL and increase the contents of intracellular triglyceride (TG) and total cholesterol (TC) in RAW264.7 macrophages. In addition, intracellular molecules PI3K, AKT and PPARγ were significantly up-regulated and activated in resitin-stimulated RAW264.7 macrophages (P < 0.05). In contrast, the effects of resistin on RAW264.7 macrophages could be abrogated by specific inhibitors for LPL (LPL-siRNA) and PI3K/AKT signaling pathway (LY294002). All together, this study demonstrated that resistin could up-regulate the expression of LPL and induce lipid accumulation in RAW264.7 macrophages. More importantly, the PPARγ-dependent PI3K/AKT signaling pathway was relevant to the lipid accumulation process in resistin-stimulated macrophages.

Effects of aflatoxin B1 on the cell cycle distribution of splenocytes in chickens

The purpose of the present study was to evaluate effects of aflatoxin B1 (AFB1) on the cell cycle and proliferation of splenic cells in chickens. A total of 144 one-day-old Cobb male chickens were randomly divided into 2 equal groups of 72 each and were fed on diets as follows: a control diet and a 0.6 mg/kg AFB1 diet for 21 days. The AFB1 diet reduced body weight, absolute weight and relative weight of the spleen in broilers. Histopathological lesions in AFB1 groups were characterized as slight congestion in red pulp and lymphocytic depletion in white pulp. Compared with the control group, the expression levels of ataxia-telangiectasia mutated (ATM), cyclin E1, cyclin-dependent kinases 6 (CDK6), CDK2, p53, p21 and cyclin B3 mRNA were significantly increased, while the mRNA expression levels of cyclin D1, cdc2 (CDK1), p16, p15 were significantly decreased in the AFB1 groups. Significantly decreased proliferating cell nuclear antigen (PCNA) expression and arrested G0G1 phases of the cell cycle were also seen in the AFB1 groups. In conclusion, dietary AFB1 could induce cell cycle blockage at G0G1 phase and impair the immune function of the spleen. Cyclin D1/CDK6 complex, which inhibits the activin/nodal signaling pathway, might play a significant role in the cell cycle arrest induced by AFB1.

Selenium Ameliorates AFB1-Induced Excess Apoptosis in Chicken Splenocytes Through Death Receptor and Endoplasmic Reticulum Pathways

Aflatoxin B₁ (AFB₁) can cause hepatotoxicity, genotoxicity, and immunosuppressive effects for a variety of organisms. Selenium (Se), as an essential nutrient element, plays important protective effects against cell apoptosis induced by AFB₁. This research aimed to reveal the ameliorative effects of selenium on AFB₁-induced excess apoptosis in chicken splenocytes through death receptor and endoplasmic reticulum pathways in vivo. Two hundred sixteen neonatal chickens, randomized into four treatments, were fed with basal diet (control treatment), 0.4 mg/kg Se supplement (+Se treatment), 0.6 mg/kg AFB₁ (AFB₁ treatment), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se (AFB₁ + Se treatment) during 21 days of experiment, respectively. Compared with the AFB₁ treatment, the levels of splenocyte apoptosis in the AFB₁ + Se treatment were obviously dropped by flow cytometry and TUNEL assays although they were still significantly higher than those in the control or + Se treatments. Furthermore, the mRNA expressions of CASP-3, CASP-8 and CASP-10, GRP78, GRP94, TNF-α, TNF-R1, FAS, and FASL of splenocytes in the AFB₁ + Se treatment by qRT-PCR assay were significantly decreased compared with the AFB₁ treatment. These results indicate that Se could partially ameliorate the AFB₁-caused excessive apoptosis of chicken splenocytes through downregulation of endoplasmic reticulum and death receptor pathway molecules. This research may rich the knowledge of the detoxification mechanism of Se on AFB₁-induced apoptosis.

Sodium Fluoride Arrests Renal G2/M Phase Cell-Cycle Progression by Activating ATM-Chk2-P53/Cdc25C Signaling Pathway in Mice

BACKGROUND/AIMS

Excessive fluoride intake can induce cytotoxicity, DNA damage and cell-cycle changes in many tissues and organs, including the kidney. However, the underlying molecular mechanisms of fluoride-induced renal cell-cycle changes are not well understood at present. In this study, we used a mouse model to investigate how sodium fluoride (NaF) induces cell-cycle changes in renal cells.

METHODS

Two hundred forty ICR mice were randomly assigned to four equal groups for intragastric administration of NaF (0, 12, 24 and 48 mg/kg body weight/day) for 42 days. Kidneys were taken to measure changes of the cell-cycle at 21 and 42 days of the experiment, using flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot methods.

RESULTS

NaF, at more than 12 mg/kg body weight, induced G2/M phase cell-cycle arrest in the renal cells, which was supported by the finding of significantly increased percentages of renal cells in the G2/M phase. We found also that G2/M phase cell-cycle arrest was accompanied by up-regulation of p-ATM, p-Chk2, p-p53, p-Cdc25C, p-CDK1, p21, and Gadd45a protein expression levels; up-regulation of ATM, Chk2, p53, p21, and Gadd45a mRNA expression levels; down-regulation of CyclinB1, mdm2, PCNA protein expression levels; and down-regulation of CyclinB1, CDK1, Cdc25C, mdm2, and PCNA mRNA expression levels.

CONCLUSION

In this mouse model, NaF, at more than 12 mg/ kg, induced G2/M phase cell-cycle arrest by activating the ATM-Chk2-p53/Cdc25C signaling pathway, which inhibits the proliferation of renal cells and development of the kidney. Activation of the ATM-Chk2-p53/Cdc25C signaling pathway is the mechanism of NaF-induced renal G2/M phase cell-cycle arrest in this model.

A mini review of fluoride-induced apoptotic pathways

Fluorine or fluoride can have toxic effects on bone tissue and soft tissue at high concentrations. These negative effects include but not limited to cytotoxicity, immunotoxicity, blood toxicity, and oxidative damage. Apoptosis plays an important role in fluoride-induced toxicity of kidney, liver, spleen, thymus, bursa of Fabricius, cecal tonsil, and cultured cells. Here, apoptosis activated by high level of fluoride has been systematically reviewed, focusing on three pathways: mitochondrion-mediated, endoplasmic reticulum (ER) stress-mediated, and death receptor-mediated pathways. However, very limited reports are focused on the death receptor-mediated apoptosis pathways in the fluoride-induced apoptosis. Therefore, understanding and discovery of more pathways and molecular mechanisms of fluoride-induced apoptosis may contribute to designing measures for preventing fluoride toxicity.

Ameliorative effects of selenium on the excess apoptosis of the jejunum caused by AFB1 through death receptor and endoplasmic reticulum pathways

Aflatoxin B1 (AFB1), one of most potent and common mycotoxins in human food and animal feed, has hepatotoxic and carcinogenic effects on humans and poultry. Recent studies indicated that selenium (Se) has a protective effect on apoptosis induced by toxin poisoning. The present study was designed to reveal the ameliorative effects of selenium on the expression of apoptosis related molecules in the jejunum of broilers exposed to an AFB1 diet for 3 weeks. A total of 216 one-day-old healthy Cobb broilers were randomly divided into the control group (0 mg kg-1 AFB1), AFB1 group (0.6 mg kg-1 AFB1), AFB1 + Se group (0.6 mg kg-1 AFB1 + 0.4 mg kg-1 supplement Se) and Se group (0.4 mg kg-1 supplement Se), respectively. TUNEL and flow cytometry assays both indicated that 0.4 mg kg-1 selenium could ameliorate excess apoptosis caused by AFB1 in jejunal cells. Moreover, the expressions of FAS, FASL, TNF-α, TNF-R1, CASPASE-3, CASPASE-8, CASPASE-10, GRP78 and GRP94 analyzed by qRT-PCR demonstrated that 0.4 mg kg-1 selenium restored these parameters to be close to those in the control group. In summary, supplementation of selenium at a concentration of 0.4 mg kg-1 selenium could protect the chicken's jejunum from excess apoptosis caused by 0.6 mg kg-1 AFB1 through down-regulating the expression of death receptor pathway and endoplasmic reticulum pathway related molecules. According to this conclusion, this study may contribute to a better understanding of selenium's protective role against AFB1 poisoning.

Ageratina adenophora induces mice hepatotoxicity via ROS-NLRP3-mediated pyroptosis

Increasing evidences have demonstrated that Ageratina adenophora (A. adenophora) can cause hepatotoxicity of animals. Liver is an important site in immune regulation and inflammatory responses. However, the information about hepatotoxicity induced by A. adenophora in relation to inflammation is still finite. To investigate the underlying mechanism, we conducted animal experiments with different dosage of A. adenophora. Mice were randomly divided into 4 groups and administrated with 0%, 10%, 20% and 30% levels of A. adenophora pallet diet in control, group A, B and C, respectively. The results showed that A. adenophora caused hepatotoxicity as revealed by increasing alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase. Then, the reactive oxygen species (ROS) levels were shown to be elicited by A. adenophora through flow cytometry assay in a dose-dependent manner. Furthermore, pyroptosis was activated by A. adenophora, which was characterized by increasing protein and mRNA levels of caspase-1, gasdermin D and interleukin-1β. Notably, ROS down-stream factors, including nod-like receptor inflammasome protein 3 and nuclear factor-κB, were also activated by A. adenophora. These data demonstrated that A. adenophora caused liver inflammatory injury and induced hepatocyte pyroptosis by activating NLRP3 inflammasome, which was triggered by elevating ROS production levels. This research might provide new insights into the mechanism of hepatotoxicity induced by A. adenophora.

The Protective Role of Selenium in AFB1-Induced Tissue Damage and Cell Cycle Arrest in Chicken's Bursa of Fabricius

Aflatoxin B₁ (AFB₁) is a naturally occurring secondary metabolites of Aspergillus flavus and Aspergillus parasiticus, and is the most toxic form of aflatoxins. Selenium (Se) with antioxidant and detoxification functions is one of the essential trace elements for human beings and animals. This study aims to evaluate the protective effects of Se on AFB₁-induced tissue damage and cell cycle arrest in bursa of Fabricius (BF) of chickens. The results showed that a dietary supplement of 0.4 mg·kg^-1 Se alleviated the histological lesions induced by AFB₁, as demonstrated by decreasing vacuoles and nuclear debris, and relieving oxidative stress. Furthermore, flow cytometry studies showed that a Se supplement protected AFB₁-induced G₂M phase arrest at 7 days and G₀G₁ phase arrest at 14 and 21 days. Moreover, the mRNA expression results of ATM, Chk2, p53, p21, cdc25, PCNA, cyclin D₁, cyclin E₁, cyclin B₃, CDK6, CDK2, and cdc2 indicated that Se supplement could restore these parameters to be close to those in the control group. It is concluded that a dietary supplement of 0.4 mg kg^-1 Se could diminish AFB₁-induced immune toxicity in chicken's BF by alleviating oxidative damage and cell cycle arrest through an ATM-Chk2-cdc25 route and the ATM-Chk2-p21 pathway.

Acinetobacter lwoffii, an emerging pathogen for fish in Schizothorax genus in China

Acinetobacter lwoffii, a serious human pathogen, has been identified as a cause of nosocomial infections such as bacteremia, pneumonia and meningitis. There are only a few studies reporting A. lwoffii as a pathogen of fish. During 2016 and 2017, six bacterial strains, isolated from diseased fish of the Schizothorax genus, were identified as A. lwoffii by morphology, biochemical tests, 16S rDNA and gyrB gene sequencing analysis. One of these isolates was selected for experimental infection of Sclizothorax prenanti, Schizothorax davidi and Schizothorax wangchiachii, to confirm its pathogenicity. Experimentally infected fish showed similar symptoms to those observed in fish after natural outbreaks. Susceptibility of the isolates to 14 antibiotics was tested using a disc diffusion method; all isolates were resistant to cephalothin, aminoglycosides and β-lactams, and sensitive only to some fluoroquinolones and tetracyclines. Histological examination revealed that A. lwoffii infection could cause pathological lesions in multiple organs and tissues, especially in liver, kidney, spleen and heart. These lesions included extensive haemorrhage, vacuolar degeneration, necrosis and inflammatory cell infiltration. To our knowledge, this is the first report on A. lwoffii as a virulent pathogen for fish of the Schizothorax genus.

The mitochondrial pathway is involved in sodium fluoride (NaF)-induced renal apoptosis in mice

The objective of the present study was to explore the molecular mechanism of apoptosis induced by sodium fluoride (NaF) in the mouse kidney by using the methods of flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and experimental pathology. 240 four-week-old ICR mice were randomly divided into 4 groups and exposed to different concentrations of NaF (0 mg kg-1, 12 mg kg-1, 24 mg kg-1 and 48 mg kg-1) for a period of 42 days. The results demonstrated that NaF increased cell apoptosis and the depolarization of the mitochondrial membrane potential (MMP), and that the mitochondrial pathway was involved in NaF-induced apoptosis. Alteration of the mitochondrial pathway was characterized by significantly increasing mRNA and protein expression levels of cytosolic cytochrome c (Cyt c), the second mitochondrial activator of caspases/direct inhibitors of the apoptosis binding protein with low pI (Smac/Diablo), the serine protease high-temperature-requirement protein A2/Omi (HtrA2/Omi), the apoptosis inducing factor (AIF), endonuclease G (Endo G), cleaved-cysteine aspartate specific protease-9 (cleaved-caspase-9), cleaved-cysteine aspartate specific protease-3 (cleaved-caspase-3), Bcl-2 antagonist killer (Bak), Bcl-2 associated X protein (Bax), Bcl-2 interacting mediator of cell death (Bim), cleaved-poly-ADP-ribose polymerase (cleaved-PARP), p-p53, and decreasing mRNA and protein expression levels of B-cell lymphoma-2 (Bcl-2), Bcl-extra large (Bcl-xL), and X chromosome-linked inhibitors of apoptosis proteins (XIAPs). To our knowledge, the mitochondrial pathway is reported for the first time in NaF-induced apoptosis of the human or animal kidney. Also, this study provides novel insights for further studying fluoride-induced nephrotoxicity.

[Resistin promotes the production of inflammatory factors in cultured bovine alveolar macrophages and its mechanism]

Objective To explore the relationship between resistin and PPARγ and to investigate the pro-inflammatory functions of bovine resistin. Methods Bovine alveolar macrophages (BAMs) were incubated with 100 ng/mL bovine-resistin for 0, 1.5, 3, 6, 12, 24 hours, respectively. The mRNA expression levels of PPARγ, NF-κB, and resistin were tested by qRT-PCR, the protein expression levels of PPARγ and NF-κB were analyzed by Western blot analysis, and the levels of pro-inflammatory cytokines (IL-1β and TNF-α) in the supernatant were measured by ELISA. Results After BAMs were treated with resistin for 1.5 hours, the level of PPARγ of BAMs was significantly reduced and there was a time dependent effect. Meanwhile, the mRNA levels of NF-κB and resistin in BAMs increased significantly since induced by bovine resistin for 6 hours and to peak at 12 hours. The protein expression of PPARγ in BAMs decreased significantly after incubating with bovine-resistin for 12 hours, while the expression of NF-κB increased significantly at 12 hours. Both IL-1β and TNF-α increased in a time-dependent manner after 1.5 hours. Conclusion Bovine-resistin might induce BAMs producing pro-inflammatory cytokines such as IL-1β and TNF-α via inhibiting PPARγ whereas activating the NF-κB mediated pathway.

The comparison of thoracoscopic-laparoscopic esophagectomy and open esophagectomy: A meta-analysis

OBJECTIVE

The objective of this study was to perform a meta-analysis to evaluate the effects of thoracoscopic-laparoscopic esophagectomy (TLE) and open esophagectomy (OE) in the treatment of esophageal cancer.

METHODS

A literature search was performed using PubMed, Embase, and Google Scholar databases for relevant keywords and the medical subject headings. After we had screened further, 13 clinical trials were included in the final meta-analysis. Specific odds ratios (ORs), standardized mean differences (SMDs), mean differences (MDs), and confidence intervals (CIs) were calculated.

RESULTS

The outcomes of treatment effects included anastomotic leakage, blood loss, number of lymph nodes harvested, and operating time. Comparing OE for esophageal cancer patients, the pooled OR of anastomotic leakage was 0.89 (95% CI = [0.47, 1.68]), the pooled SMD of blood loss was - 0.56 (95% CI = [-0.77, -0.35]), the pooled MD of lymph nodes harvested was - 0.93 (95% CI = [-2.35, 0.50]), and the pooled SMD of operating time was 0.31 (95% CI = [0.02, 0.59]).

CONCLUSION

TLE was found to significantly decrease patients' blood loss. There is no difference of anastomotic leakage and the number of lymph nodes harvested between TLE and OE.

Protective Role of Selenium in Immune-Relevant Cytokine and Immunoglobulin Production by Piglet Splenic Lymphocytes Exposed to Deoxynivalenol

Deoxynivalenol (DON) is a mycotoxin that causes immunosuppression, especially in swine. Selenium (Se) is essential for proper functioning of the immune system in animals. However, little is known about the effects of DON and Se on cytokine or immunoglobulin production in piglets. Here, we addressed this gap by examining piglet splenic lymphocyte responses in vitro. Cells were stimulated with concanavalin A, a T cell stimulatory lectin, in the absence or presence of DON (0.1, 0.2, 0.4, and 0.8 μg/mL), Se (Na₂SeO₃, 2 μM), or combinations of Se 2 μM and DON 0.1-0.8 μg/mL for 12, 24, or 48 h. At each time point, supernatants and cells were collected and the expression of cytokine and immunoglobulin protein and mRNA was examined. Compared with control and Se-alone treatments, DON exposure significantly and dose dependently decreased the expression levels of IL-2, IL-4, IL-6, IL-10, IFN-γ, IgG, and IgM mRNA and protein. By contrast, co-treatment with DON + Se significantly increased the mRNA and protein levels of all factors examined, except IL-4 and IL-6, compared with DON treatment alone. The results of this investigation demonstrate that Se has the potential to counteract DON-induced immunosuppression in piglets and is a promising treatment for DON-mediated toxicity.

Occurrence and genetic characterization of Giardia duodenalis and Cryptosporidium spp. from adult goats in Sichuan Province, China

Giardia duodenalis and Cryptosporidium spp. are common gastrointestinal protozoa in mammals. Many studies have been conducted on the distribution of G. duodenalis and Cryptosporidium spp. genotypes in sheep and cattle. However, in China, information about molecular characterization and genetic analysis of G. duodenalis and Cryptosporidium spp. in goats is limited. In this study, 342 fecal samples from adult goats were collected from 12 farms in Sichuan Province, China. The occurrence of G. duodenalis and Cryptosporidium spp. in adult goats was 14.9% (51/342) and 4.7% (16/342), respectively. All G. duodenalis were identified as assemblage E, with two novel genotypes (assemblages E17 and E18) being detected at the beta-giardin (bg) locus. Based on three loci-beta-giardin (bg), triose phosphate isomerase (tpi), and glutamate dehydrogenase (gdh)-multilocus sequence typing revealed three novel multilocus genotypes (MLGs) of assemblage E (MLG-E1, E2, E3 (sc)). Small Subunit (SSU) rRNA-based PCR identified two Cryptosporidium species, namely C. xiaoi (11/16) and C. suis (5/16). This study is not only the first to report C. suis infection in adult goats in China but is also the first to use the MLG approach to identify G. duodenalis in adult goats.

Molecular characterization and new genotypes of Enterocytozoon bieneusi in pet chipmunks (Eutamias asiaticus) in Sichuan province, China

BACKGROUND

Enterocytozoon bieneusi, the most commonly identified microsporidian species in humans, is also identified in livestock, birds, rodents, reptiles, companion animals, even wastewater. However, there is no information available on occurrence of E. bieneusi in pet chipmunks. The aim of the present study was to determine the genotypes, molecular characterization of E. bieneusi in pet chipmunks, and assess the zoonotic potential.

RESULTS

A total of 279 fecal specimens were collected from chipmunks from seven pet shops and one breeding facility in Sichuan province, China. The prevalence for E. bieneusi was 17.6% (49/279) based on nested PCR targeting the internal transcribed spacer (ITS) region. The prevalence of E. bieneusi in chipmunks < 90 days of age was significantly higher than that in older chipmunks; however, differences among different sources and between genders were not significant. Eight genotypes of E. bieneusi were identified, including four known genotypes (D, Nig7, CHG9, and CHY1) and four novel genotypes (SCC-1 to 4). Phylogenetic analysis classified these genotypes into four distinct groups as follows: genotypes D and CHG9 clustered into group 1 of zoonotic potential; genotypes Nig7 and CHY1 clustered into group 6 and a new group, respectively; the four novel genotypes (SCC-1 to 4) formed a separate group named group 10.

CONCLUSIONS

To the best of our knowledge, this is the first study reporting the prevalence and genotypes of E. bieneusi in pet chipmunks in China. Genotypes D and Nig7, found in chipmunks in this study, have also been previously identified in humans, which suggests that chipmunks might play a role in the transmission of this pathogen to humans.

Activation of the porcine alveolar macrophages via toll-like receptor 4/NF-κB mediated pathway provides a mechanism of resistin leading to inflammation

Resistin, a previously discovered cysteine-rich adipokine known to regulate glucose metabolism, has been emerged as a mediator in inflammation and immunity. Its level was supposed to be related to the expression of indicators, such as interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) in inflammation. Toll-like receptor 4 (TLR4) was reported to be a receptor for resistin in cells, like leukocytes and peripheral blood mononuclear cells (PBMC). However, the pro-inflammatory role of resistin and its intracellular mechanisms in alveolar macrophages have not been thoroughly validated. Here we found that the pro-inflammatory cytokine expression in porcine alveolar macrophages (PAMs) was positively correlated with resistin. Our results also showed that resistin induced the expression of TLR4, intracellular molecules myeloid differentiation primary response protein 88 (MyD88), TRIF-related adaptor molecule (TRAM) and nuclear factor κB (NF-κB) in PAMs. In contrast, inhibition of TLR4, MyD88, TRAM and NF-κB abrogated the pro-inflammatory effect of resistin on PAMs. Additionally, the associations among TLR4, MyD88/TRAM and NF-κB were investigated by introducing TLR4-siRNA, MyD88-siRNA and TRAM-siRNA respectively into PAMs prior to the treatment with resistin. Taken together, our findings demonstrated that resistin promoted the production of pro-inflammatory cytokine in PAMs via TLR4/NF-κB-mediated pathway (TLR4/MyD88/TRAM/NF-κB).

Sodium fluoride causes oxidative stress and apoptosis in the mouse liver

The current study was conducted to investigate the effect of sodium fluoride (NaF) on the oxidative stress and apoptosis as well as their relationship in the mouse liver by using methods of flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR), western blot, biochemistry and experimental pathology. 240 four-week-old ICR mice were randomly divided into 4 groups and exposed to different concentration of NaF (0 mg/kg, 12 mg/kg, 24 mg/kg and 48 mg/kg) for a period of 42 days. The results showed that NaF caused oxidative stress and apoptosis. NaF-caused oxidative stress was accompanied by increasing reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and decreasing mRNA expression levels and activities of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GSH-PX) and glutathione-s-transferase (GST). NaF induced apoptosis via tumor necrosis factor recpter-1 (TNF-R1) signaling pathway, which was characterized by significantly increasing mRNA and protein expression levels of TNF-R1, Fas associated death domain (FADD), TNFR-associated death domain (TRADD), cysteine aspartate specific protease-8 (caspase-8) and cysteine aspartate specific protease-3 (caspase-3) in dose- and time-dependent manner. Oxidative stress is involved in the process of apoptotic occurrence, and can be triggered by promoting ROS production and reducing antioxidant function. NaF-caused oxidative stress and apoptosis finally impaired hepatic function, which was strongly supported by the histopathological lesions and increased serum alanine amino transferase (ALT), aspartic acid transferase (AST), alkaline phosphatase (AKP) activities and TBIL contents.

Histopathological Injuries, Ultrastructural Changes, and Depressed TLR Expression in the Small Intestine of Broiler Chickens with Aflatoxin B₁

To explore AFB₁-induced damage of the small intestine, the changes in structure and expression of TLRs (Toll-like Receptors) in the small intestine of chickens were systematically investigated. Ninety healthy neonatal Cobb chickens were randomized into a control group (0 mg/kg AFB₁) and an AFB₁ group (0.6 mg/kg AFB₁). The crypt depth of the small intestine in the AFB₁ group was significantly increased in comparison to the control chickens, while the villus height and area were evidently decreased, as well as the villus:crypt ratio and epithelial thickness. The histopathological observations showed that the villi of the small intestine exposed to AFB₁ were obviously shedding. Based on ultrastructural observation, the absorptive cells of small intestine in the AFB₁ group exhibited fewer microvilli, mitochondrial vacuolation and the disappearance of mitochondrial cristae, and junctional complexes as well as terminal web. Moreover, the number of goblet cells in the small intestine in the AFB₁ group significantly decreased. Also, AFB₁ evidently decreased the mRNA expression of TLR2-2, TLR4, and TLR7 in the small intestine. Taken together, our study indicated that dietary 0.6 mg/kg AFB₁ could induce histopathological injuries and ultrastructural changes, and depress levels of TLR mRNA in the chicken small intestine.

Sodium fluoride (NaF) causes toxic effects on splenic development in mice

At present, very limited studies focus on the toxic effect of sodium fluoride (NaF) on splenic development of human and animals in vivo. This study was firstly designed to evaluate the toxic effects of NaF on the splenic development of mice in vivo by observing histopathological lesions, changes of splenic growth index (GI), T and B cells, immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM) contents, cytokine protein expression levels, and cell cycle and cyclins/cdks protein expression levels using the methods of pathology, flow cytometry (FCM), western blot (WB), and enzyme-linked immunosorbent assay (ELISA). A total of 240 ICR mice were equally allocated into four groups with intragastric administration of distilled water in the control group and 12, 24, 48 mg/kg NaF solution in the experimental groups for 42 days. The results showed that NaF in 12 mg/kg and over caused the toxic effects on splenic development, which was characterized by reducing growth index and lymphocytes in the white and red pulp histopathologically, increasing cell percentages of the G0/G1 phase and decreasing cell percentages of the S phase, and reducing T cells and B cells as well as IgA, IgG, and IgM contents when compared with those in the control group. Concurrently, cytokines including interleukin-2 (IL-2), transforming growth factor beta (TGF-β), tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ) and cyclin (E/D and CDK2/4) protein expression levels were markedly decreased (P < 0.05 or P < 0.01), and interleukin-10 (IL-10) protein expression levels were significantly increased (P < 0.05 and P < 0.01) in the three NaF-treated groups. Toxic effects finally impaired the splenic cellular immunity and humoral immunity due to the reduction of T and B cell population and activity. Cell cycle arrest is the molecular basis of NaF-caused toxic effects on the splenic development.

Induction of apoptosis and autophagy via mitochondria- and PI3K/Akt/mTOR-mediated pathways by E. adenophorum in hepatocytes of saanen goat

E. adenophorum has reported to cause hepatotoxicity. But, the precise effects of E. adenophorum on hepatocytes is unclear. Saanen goats were fed on E. adenophorum to detect the cytotoxicity effects of E. adenophorum on hepatocytes. Our study has shown that the typical apoptotic features, the increasing apoptotic hepatocytes and activated caspase-9, −3 and the subsequent cleavage of PARP indicated the potent pro-apoptotic effects of E. adenophorum. Moreover, the translocation of Bax and Cyt c between mitochondria and cytosol triggering the forming of apoptosome proved that the mitochondria-mediated apoptosis was triggered by E. adenophorum. Furthermore, E. adenophorum increased the MDC-positive autophagic vacuoles and the subcellular localization of punctate LC3, the ratio of LC3-II/LC3-I and the protein levels of Beclin 1, but decreased that of P62, indicating the potent pro-autophagic effects of E. adenophorum. In addition, E. adenophorum significantly inhibited the protein leves of p-PI3K, p-Akt and p-mTORC1, but increased PTEN and p-AMPK. Also, the p-mTORC2 and p-Akt Ser473 were inhibited, indicating that the supression of mTORC2/Akt pathway could induce the autophagy of hepatocytes. The autophagy-realted results indicated that the inhibition of PI3K/Akt/mTORC1- and mTORC2/Akt-mediated pathways contributed to the pro-autophagic activity of E. adenophorum. These findings provide new insights to understand the mechanisms involved in E. adenophorum-caused hepatotoxicity of Saanen goat.

Sodium fluoride induces apoptosis in cultured splenic lymphocytes from mice

Though fluorine has been shown to induce apoptosis in immune organs in vivo, there has no report on fluoride-induced apoptosis in the cultured lymphocytes. Therefore, this study was conducted with objective of investigating apoptosis induced by sodium fluoride (NaF) and the mechanism behind that in the cultured splenic lymphocytes by flow cytometry, western blot and Hoechst 33258 staining. The splenic lymphocytes were isolated from 3 weeks old male ICR mice and exposed to NaF (0, 100, 200, and 400 μmol/L) in vitro for 24 and 48 h. When compared to control group, flow cytometry assay and Hoechst 33258 staining showed that NaF induced lymphocytes apoptosis, which was promoted by decrease of mitochondria transmembrane potential, up-regulation of Bax, Bak, Fas, FasL, caspase 9, caspase 8, caspase 7, caspase 6 and caspase 3 protein expression (P < 0.05 or P <0.01), and down-regulation of Bcl-2 and Bcl-xL protein expression (P <0.05 or P <0.01). The above-mentioned data suggested that NaF-induced apoptosis in splenic lymphocytes could be mediated by mitochondrial and death receptor pathways.

Inflammatory responses and inflammation-associated diseases in organs

Inflammation is a biological response of the immune system that can be triggered by a variety of factors, including pathogens, damaged cells and toxic compounds. These factors may induce acute and/or chronic inflammatory responses in the heart, pancreas, liver, kidney, lung, brain, intestinal tract and reproductive system, potentially leading to tissue damage or disease. Both infectious and non-infectious agents and cell damage activate inflammatory cells and trigger inflammatory signaling pathways, most commonly the NF-κB, MAPK, and JAK-STAT pathways. Here, we review inflammatory responses within organs, focusing on the etiology of inflammation, inflammatory response mechanisms, resolution of inflammation, and organ-specific inflammatory responses.

Inflammatory responses and inflammation-associated diseases in organs

Inflammation is a biological response of the immune system that can be triggered by a variety of factors, including pathogens, damaged cells and toxic compounds. These factors may induce acute and/or chronic inflammatory responses in the heart, pancreas, liver, kidney, lung, brain, intestinal tract and reproductive system, potentially leading to tissue damage or disease. Both infectious and non-infectious agents and cell damage activate inflammatory cells and trigger inflammatory signaling pathways, most commonly the NF-κB, MAPK, and JAK-STAT pathways. Here, we review inflammatory responses within organs, focusing on the etiology of inflammation, inflammatory response mechanisms, resolution of inflammation, and organ-specific inflammatory responses.

The molecular mechanism of G2M cell cycle arrest induced by AFB1 in the jejunum

Aflatoxin B1 (AFB1) has potent hepatotoxic, carcinogenic, genotoxic, immunotoxic and other adverse effects in human and animals. The aim of this study was to investigate the molecular mechanism of G2/M cell cycle arrest induced by AFB1 in the jejunum of broilers. Broilers, as experimental animals, were fed 0.6 mg/kg AFB1 diet for 3 weeks. Our results showed that AFB1 reduced the jejunal villus height, villus height/crypt ratio and caused G2/M cell cycle arrest. The G2/M cell cycle was accompanied by the increase of ataxia telangiectasia mutated (ATM), p53, Chk2, p21 protein and mRNA expression, and the decrease of Mdm2, cdc25C, cdc2, cyclin B and proliferating cell nuclear antigen protein and mRNA expression. In conclusion, AFB1 blocked G2/M cell cycle by ATM pathway in the jejunum of broilers.

The Molecular Mechanisms of Protective Role of Se on the G2/M Phase Arrest of Jejunum Caused by AFB1

Aflatoxin B₁ (AFB₁) is the most toxic among the mycotoxins and causes detrimental health effects on human and animals. Selenium (Se) plays an important role in chemopreventive, antioxidant, anticarcinogen, and detoxification and involved in cell cycle regulation. The aim of this study was to explore the molecular mechanisms of selenium involved in inhibition of G₂/M cell cycle arrest of broiler's jejunum. A total of 240 one-day-old healthy Cobb broilers were randomly divided into four groups and fed with basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se (+Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se (AFB₁ + Se group) for 21 days, respectively. The histological observation and morphological analysis revealed that 0.4 mg/kg Se prevented the AFB₁-associated lesions of jejunum including the shedding of the apical region of villi, the decreased villus height, and villus height/crypt ratio. The cell cycle analysis by flow cytometry showed that 0.4 mg/kg Se ameliorated the AFB₁-induced G₂/M phase arrest in jejunal cells. Moreover, the expressions of ATM, Chk2, p53, Mdm2, p21, PCNA, Cdc25, cyclin B, and Cdc2 analyzed by immunohistochemistry and qRT-PCR demonstrated that 0.4 mg/kg Se restored these parameters to be close to those in the control group. In conclusion, Se promoted cell cycle recovery from the AFB₁-induced G₂/M phase arrest by the molecular regulation of ATM pathway in the jejunum of broilers. The outcomes from the present study may lead to a better understanding of the nature of selenium's essentiality and its protective roles against AFB₁.

Sodium fluoride causes hepatocellular S-phase arrest by activating ATM-p53-p21 and ATR-Chk1-Cdc25A pathways in mice

In this study, experimental pathology, flow cytometry (FCM), quantitative real-time polymerase chain reaction (qRT-PCR), and western blot (WB) were used to evaluate the effects of sodium fluoride (NaF) on hepatocellular cell cycle progression in mice. A total of 240 ICR mice were divided equally into four groups; the experimental groups received 12, 24, or 48 mg/kg NaF intragastrically for 42 days, while the control group received distilled water. Doses of NaF above 12 mg/kg increased the percentage of cells in S phase (S-phase arrest), reduced percentages of cells in G0/G1 or G2/M phase, and activated the ATM-p53-p21 and ATR-Chk1-Cdc25A pathways. Activation of these pathways was characterized by up-regulation of ATM, p53, p21, ATR, and Chk1 mRNA and protein expression, and down-regulation of Cdc25A, cyclin E, cyclin A, CDK2, CDK4, and proliferating cell nuclear antigen (PCNA) mRNA and protein expression. These results indicate that NaF caused S-phase arrest by activating the ATM-p53-p21 and ATR-Chk1-Cdc25A pathways.

Sodium fluoride induces apoptosis in mouse splenocytes by activating ROS-dependent NF-κB signaling

In this study, we investigated the roles of reactive oxygen species (ROS) and nuclear factor-κB (NF-κB) signaling in sodium fluoride-induced DNA damage and apoptosis in mouse splenocytes. Intragastric administration of 12, 24 or 48 mg/kg sodium fluoride resulted in a time- and dose-dependent increase in DNA fragmentation and apoptosis in mouse splenocytes on days 21 and 42. High ROS levels correlated with increased levels of phosphorylated IκB kinase and NF-κB p65 and decreased levels of inhibitory kappa B protein in splenocytes from mice treated with sodium fluoride. Moreover, splenocytes from sodium fluoride-treated mice showed high expression of pro-apoptotic proteins, including Bim, Bax, Bak, caspase-3 and poly ADP-ribose polymerase, and low expression of the anti-apoptotic proteins BcL-2 and BcL-xL. These results show that sodium fluoride induces apoptosis in mouse splenocytes by enhancing ROS-dependent NF-κB signaling.

Nickel chloride (NiCl2) in hepatic toxicity: apoptosis, G2/M cell cycle arrest and inflammatory response

Up to now, the precise mechanism of Ni toxicology is still indistinct. Our aim was to test the apoptosis, cell cycle arrest and inflammatory response mechanism induced by NiCl₂ in the liver of broiler chickens. NiCl₂ significantly increased hepatic apoptosis. NiCl₂ activated mitochondria-mediated apoptotic pathway by decreasing Bcl-2, Bcl-xL, Mcl-1, and increasing Bax, Bak, caspase-3, caspase-9 and PARP mRNA expression. In the Fas-mediated apoptotic pathway, mRNA expression levels of Fas, FasL, caspase-8 were increased. Also, NiCl₂ induced ER stress apoptotic pathway by increasing GRP78 and GRP94 mRNA expressions. The ER stress was activated through PERK, IRE1 and ATF6 pathways, which were characterized by increasing eIF2α, ATF4, IRE1, XBP1 and ATF6 mRNA expressions. And, NiCl₂ arrested G₂/M phase cell cycle by increasing p53, p21 and decreasing cdc2, cyclin B mRNA expressions. Simultaneously, NiCl₂ increased TNF-α, IL-1β, IL-6, IL-8 mRNA expressions through NF-κB activation. In conclusion, NiCl₂ induces apoptosis through mitochondria, Fas and ER stress-mediated apoptotic pathways and causes cell cycle G₂/M phase arrest via p53-dependent pathway and generates inflammatory response by activating NF-κB pathway.

Effects of sodium fluoride on blood cellular and humoral immunity in mice

Exposure to high fluorine can cause toxicity in human and animals. Currently, there are no systematic studies on effects of high fluorine on blood cellular immunity and humoral immunity in mice. We evaluated the alterations of blood cellular immunity and humoral immunity in mice by using flow cytometry and ELISA. In the cellular immunity, we found that sodium fluoride (NaF) in excess of 12 mg/Kg resulted in a significant decrease in the percentages of CD3+, CD3+CD4+, CD3+CD8+ T lymphocytes in the peripheral blood. Meanwhile, serum T helper type 1 (Th1) cytokines including interleukin (IL)-2, interferon (IFN)-γ, tumor necrosis factor (TNF), and Th2 cytokines including IL-4, IL-6, IL-10, and Th17 cytokine (IL-17A) contents were decreased. In the humoral immunity, NaF reduced the peripheral blood percentages of CD19+ B lymphocytes and serum immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM). The above results show that NaF can reduce blood cellular and humoral immune function in mice, providing an excellent animal model for clinical studies on immunotoxicity-related fluorosis.

A study on the expression of apoptotic molecules related to death receptor and endoplasmic reticulum pathways in the jejunum of AFB1-intoxicated chickens

Aflatoxin B₁ (AFB₁) is a common contaminant of poultry feeds in tropical and subtropical climates. Early researches have well established the hepatotoxic, carcinogenic, and immunotoxic effects of AFB₁ on humans and animals. Recently, it has been shown that AFB₁ could cause the up- or down-alteration of mitochondrial pathway molecule expression. However, the information on the expression of death receptor and endoplasmic reticulum molecules in the jejunal apoptosis induced by AFB₁ were unavailable. So the present study was conducted to explore the expression of apoptotic molecules related to death receptor and endoplasmic reticulum in the jejunal cells of chickens exposed to AFB₁ diet for 3 weeks. Total of 144 one-day-old chickens was randomly divided into two groups, namely control group (containing 0 mg/kg AFB₁) and AFB₁ group (containing 0.6 mg/kg AFB₁). Histopathological observation and microscopic quantitative analysis revealed morphological changes in the jejunum such as the shedding of the mucosal epithelial cells in the apical region of villi along with the decrease of villus height, villus area and villus/crypt ratio in the AFB₁ group. Both TUNEL and flow cytometry assays showed that AFB₁ intake induced excessive apoptosis of jejunal cells. Quantitative real-time PCR test displayed the general upregulation of death receptors (FAS, FASL, TNF-α and TNF-R1), endoplasmic reticulum signals (GRP78 and GRP94) as well as initiator and executioner caspases (CASPASE-10, CASPASE-8 and CASPASE-3) in the jejunum of AFB₁-intoxicated chickens. It's the first study demonstrating that AFB₁ induced apoptosis of chickens’ jejunum accompanied by the alteration of death receptor and endoplasmic reticulum molecule expression.

Study on the morphology, histology and enzymatic activity of the digestive tract of Gymnocypris eckloni Herzenstein

The present research was conducted to study the morphology, histology and enzymatic activities of the digestive tract of Gymnocypris eckloni by light and transmission electron microscopes as well as by enzyme assays. The digestive tract of G. eckloni consisted of the oropharyngeal cavity, oesophagus and intestine. The wall of the digestive tract was composed of mucosa, submucosa, muscularis and serosa but lacked muscularis mucosa and glands. The stratified epithelium of the oropharyngeal cavity and oesophagus contained numerous mucous cells. Taste buds were found in the epithelium of the oropharyngeal cavity. A large number of isolated longitudinal striated muscular bundles were present in the submucosa of the oesophagus. The mucosal epithelium of the intestine was composed of simple columnar cells containing absorptive, goblet and endocrine cells. Numerous mitochondria and endoplasmic reticulum were observed in the absorptive cells, especially in the anterior intestine. From the anterior to the posterior intestine, the number and length of mucosal folds and microvilli decreased, but the number of goblet cells increased. The intestinal coefficient was 2.38. Maximum trypsin activity was measured in the anterior intestine, while the lowest lipase and amylase activities were tested in the middle and posterior intestines, respectively. The results provided experimental evidence for evaluating physiological condition of G. eckloni digestive tract, which will be useful for improving current rearing practices and diagnoses of digestive tract diseases.

Euptox A Induces G1 Arrest and Autophagy via p38 MAPK- and PI3K/Akt/mTOR-Mediated Pathways in Mouse Splenocytes

Euptox A (9-oxo-10, 11-dehydroageraphorone), the main toxin isolated from Eupatorium adenophorum, is known to induce immunotoxicity in animals. However, the precise mechanism underlying the effects of Euptox A on splenocytes is unclear. Here, we aimed to investigate the molecular mechanisms underlying the effect of Euptox A in mouse spleens after its intragastric administration and found that Euptox A exhibits proautophagic effects in splenocytes. Euptox A markedly arrested the splenocytes in the G0/G1 phase, which was accompanied by inhibition of the expression of the positive regulators CDK4, CDK2, cyclin D1, PCNA, and E2F1, and promotion of the expression of the negative regulators p53, p21 Waf1/Cip1, p27 Kip1, and Chk1. We also found that Euptox A did not markedly induce splenocyte apoptosis, but induced autophagy while increasing the subcellular localization of punctate LC3, ratio of LC3-II/LC3-I, and Beclin 1 levels, and decreasing p62 levels. Euptox A also significantly inhibited p-PI3K, p-p38 MAPK, p-Akt, and p-mTOR expression, but increased PTEN and p-AMPK expression. These results indicated that Euptox A induced splenocyte autophagy by inhibiting the PI3K/Akt/mTOR pathway, suppressing p38 MAPK expression, and activating AMPK. These findings provide new insights into the mechanisms involved in spleen toxicity caused by Euptox A in mice.

Resistin increases the expression of NOD2 in mouse monocytes

Previous studies have indicated that resistin, a type of adipokine, contributes to the development of insulin resistance and type 2 diabetes mellitus, and mediates inflammatory reactions. However, a specific receptor for resistin has not yet been identified. In this study, the relationship between resistin and nucleotide-binding oligomerization domain-like receptors, as well as resistin signal transduction, was examined through transfection, quantitative polymerase chain reaction, western blot analysis and ELISA. The mRNA expression of nucleotide-binding oligomerization domain-containing protein 2 (NOD2), a key immune receptor related to insulin resistance, was significantly increased by resistin treatment at concentrations of 100, 150 and 200 ng/ml (P<0.05, P<0.01 and P<0.01, respectively). The mRNA expression of downstream signaling molecules in the NOD2 signaling pathway, receptor-interacting serine/threonine-protein kinase 2 (RIP2; P<0.01 at 6, 12 and 24 h) and inhibitor of NF-κB kinase subunit beta (P<0.01 at 3, 6, 12 and 24 h) were significantly increased by resistin treatment compared with the control. The mRNA expression of key proinflammatory cytokines, tumor necrosis factor α, IL (interleukin)-6 and IL-1β, were also significantly increased by resistin treatment compared with the control (P<0.01). NOD2 knockdown by small interfering RNA (siRNA) significantly decreased the expression of NOD2 and RIP2 (P<0.01), and there was no significant increase in the levels of cytokines, as compared with treatment with control siRNA. These findings indicate that the inflammatory reaction induced by resistin involves the NOD2-nuclear factor (NF)-κB signaling pathway. The inhibition of NF-κB significantly decreased the secretion of key inflammatory cytokines (P<0.01), suggesting that NF-κB signaling mechanisms are essential to the resistin-induced inflammatory response.

Histopathological findings of renal tissue induced by oxidative stress due to different concentrations of fluoride

It has been reported that excessive intake of fluoride can induce renal lesions. However, its pathogenesis is still less understood. Therefore, this study was conducted to investigate oxidative damage and the relationships between the oxidative damage and renal lesions in fluoride-treated mice by using the methods of histopathology, biochemistry, flow cytometry and quantitative real-time polymerase chain reaction (qRT-PCR). A total of 240 ICR mice were randomly divided into four equal groups (sodium fluoride was given orally at the dose of 0, 12, 24 and 48 mg/kg body weight for 42 days, respectively). We found that fluoride in excess of 12 mg/kg induced renal oxidative damage, which was characterized by increasing the levels of reactive oxygen species (ROS) production and contents of malondialdehyde (MDA) and protein carbonyls (PC), and decreasing the abilities of anti-superoxide anion (ASA) and anti-hydroxyl radical (AHR), glutathione (GSH) content, as well as activities and mRNA expression levels of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GSH-Px). Concurrently, fluoride caused degeneration and necrosis of the tubular cells, renal tubular hyaline casts and glomeruli swelling, which were consistent with the alteration of renal function parameters including elevated contents of serum creatinine (Cr), serum uric acid (UA), blood urea nitrogen (BUN), and the activities of urinary N-acetyl-b-D-glucosaminidase (NAG), renal lactate dehydrogenase (LDH), and reduced activities of sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and acid phosphatase (ACP) in the kidney. The above-mentioned results showed that fluoride in excess of 12 mg/kg induced renal oxidative damage, which then caused renal lesions and dysfunctions. These findings also clearly demonstrated that oxidative damage is one of the mechanisms of fluoride-induced renal lesions and dysfunctions.

Sodium selenite prevents suppression of mucosal humoral response by AFB1 in broiler's cecal tonsil

Aflatoxin B₁ (AFB₁), the most common mycotoxin in human food and animal feed, produces hepatotoxic, genotoxic and immunosuppressive effects in multiple species. Selenium (Se) has emerged as an important element in the dietary prevention of various toxic agents. The present study was designed to scrutinize the protective effects of sodium selenite on the histological lesions and suppression of mucosal humoral response in the cecal tonsil generated by AFB₁. A total of 156 one-day-old broilers were divided into four groups and fed on basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se supplement (+Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se supplement (AFB₁+Se group) respectively for 21 days. Our results showed that 0.4 mg/kg Se supplement in broiler's diets could improve the AFB₁-induced histological lesions in the cecal tonsils including the depletion of lymphocytes in the lymphatic nodules as well as the shedding of microvilli in the absorptive cells. Moreover, Se could restore the decreased number of IgA+ cells and expression levels of pIgR, IgA, IgG, and IgM mRNA induced by AFB₁ to be close to those in the control group. These results demonstrated that 0.4 mg/kg supplemented dietary Se in the form of sodium selenite could protect the cecal tonsils from the histological lesions and suppression of the mucosal humoral response provoked by 0.6 mg/kg AFB₁. Our study may provide new experimental evidences for better understanding of AFB₁-induced damage of mucosal immunity and protective effect of Se against this toxin.

Nickel chloride (NiCl2) induces endoplasmic reticulum (ER) stress by activating UPR pathways in the kidney of broiler chickens

It has been known that overexposure to Ni can induce nephrotoxicity. However, the mechanisms of underlying Ni nephrotoxicity are still elusive, and also Ni- and Ni compound-induced ER stress has been not reported in vivo at present. Our aim was to use broiler chickens as animal model to test whether the ER stress was induced and UPR was activated by NiCl2 in the kidney using histopathology, immunohistochemistry and qRT-PCR. Two hundred and eighty one-day-old broiler chickens were divided into 4 groups and fed on a control diet and the same basal diet supplemented with 300 mg/kg, 600mg/kg and 900mg/kg of NiCl2 for 42 days. We found that dietary NiCl2 in excess of 300 mg/kg induced ER stress, which was characterized by increasing protein and mRNA expression of ER stress markers, e.g., GRP78 and GRP94. Concurrently, all the three UPR pathways were activated by dietary NiCl2. Firstly, the PERK pathway was activated by increasing eIF2a and ATF4 mRNA expression. Secondly, the IRE1 pathway was activated duo to increase in IRE1 and XBP1 mRNA expression. And thirdly, the increase of ATF6 mRNA expression suggested that ATF6 pathway was activated. The findings clearly demonstrate that NiCl2 induces the ER stress through activating PERK, IRE1 and ATF6 UPR pathways, which is proved to be a kind of molecular mechanism of Ni- or/and Ni compound-induced nephrotoxicity.

Toxic effect of NiCl2 on development of the bursa of Fabricius in broiler chickens

This study was conducted with objective of evaluating the toxic effects of nickel chloride (NiCl₂) on development of bursa of Fabricius in broilers fed on diets supplemented with 0, 300, 600 and 900 mg/kg of NiCl₂ for 42 days by using the methods of experimental pathology, flow cytometry (FCM), and quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that dietary NiCl₂ in 300 mg/kg and over induced toxic suppression in the bursal development, which was characterized by decreasing lymphocytes histopathologically and relative weight, increasing G₀/G₁ phase (a prolonged nondividing state), reducing S phase (DNA replication) and proliferating index, and increasing percentages of apoptotic cells. Concurrently, the mRNA expression levels of bax, cytochrome c (cyt c), apoptotic peptidase activating factor 1 (Apaf-1), caspase-3, caspase-6, caspase-7 and caspase-9 were increased and the bcl-2 mRNA expression levels were decreased. The toxic suppression of bursal development finally impaired humoral immunity duo to the reduction of B lymphocyte population and B lymphocyte activity in the broiler chicken. This study provides new evidences for further studying the effect mechanism of Ni and Ni compoundson B-cell or bursa of Fabricius.

Suppressive subtractive hybridization reveals different gene expression between high and low virulence strains of Cladosporium cladosporioides

Cladosporium cladosporioides is a ubiquitous fungus, causing infections in plants, humans, and animals. Suppression subtractive hybridization (SSH) and quantitative real-time PCR (qRT-PCR) were used in this study to identify differences in gene expression between two C. cladosporioides strains, the highly virulent Z20 strain and the lowly virulent Zt strain. A total of 61 unigenes from the forward library and 42 from the reverse library were identified. Gene ontology (GO) analysis showed that these genes were involved in various biological processes, cellular components and molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the unigenes in the forward library corresponded to 5 different pathways and the reverse library unigenes were involved in 3 different pathways. The qRT-PCR results indicated that expressions of APL1, GUD1, CSE1, SPBC3E7.04c and MFS were significantly different between Z20 and Zt strains, while genes encoding the senescence-associated proteins, pse1, nup107, mip1, pex2, icl1 and α/β hydrolase exhibited no significant differences between the two strains. In addition, we found that 5 unigenes encoding mip1, chk1, icl1, α/β hydrolase and β-glucosidase may be associated with pathogenicity. One unigene (MFS) may be related to the resistance to 14 α-demethylase inhibitor fungicides, and 5 unigenes (PEX2, NUP107, PSE1, APL1, and SPBC3E7.04c) may be related to either low spore yield or earlier aging of the Zt strain. Our study may help better understand the molecular mechanism of C. cladosporioides infection, and therefore improve the treatment and prevention of C. cladosporioides induced diseases.

Diet-induced obese mice exhibit altered immune responses to acute lung injury induced by Escherichia coli

OBJECTIVE

Obesity has been associated with impaired immunity and increased susceptibility to bacterial infection. It also exerts protective effects against mortality secondary to acute lung injury. The effects of obesity on immune responses to acute lung injury induced by Escherichia coli were investigated to determine if the above-mentioned differences in its effects were related to infection severity.

METHODS

Diet-induced obesity (DIO) and lean control mice received intranasal instillations of 10(9) or 10(10) CFUs of E. coli. The immune responses were examined at 0 h (uninfected), 24 h, and 96 h postinfection.

RESULTS

Following infection, the DIO mice exhibited higher leukocyte, interleukin (IL)-10, IL-6, and tumor necrosis factor-α levels and more severe lung injury than the lean mice. Following inoculation with 10(10) CFUs of E. coli, the DIO mice exhibited higher mortality and more severe inflammation-induced injury than the lean mice, but no differences in E. coli counts were noted between the two groups. However, inoculated with 10(9) CFUs of E. coli, the DIO mice exhibited smaller E. coli burdens at 24 h and 96 h after infection, as well as lower concentrations of IL-10 and tumor necrosis factor-α and less severe lung injury at 96 h after infection.

CONCLUSIONS

The results support the emerging view that obesity may be beneficial in the setting of milder infection but detrimental in the setting of more severe infection.

Dietary High Fluorine Alters Intestinal Microbiota in Broiler Chickens

This study investigated the effects of dietary high fluorine on ileal and cecal microbiota in broiler chickens. Two hundred eighty 1-day-old broiler chickens were randomly assigned to four groups and raised for 42 days. The control group was fed a corn-soybean basal diet (fluorine 22.6 mg/kg). The other three groups were fed the same basal diet, but supplemented with 400, 800, and 1200 mg/kg fluorine (high fluorine groups I, II, and III), administered in the form of sodium fluoride. The microbiota of ileal and cecal digesta was assessed with plate counts and polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE). It was found that, compared with those in the control group, the counts of Lactobacillus spp. and Bifidobacterium spp. were markedly decreased (P < 0.01 or P < 0.05), whereas the counts of Escherichia coli and Enterococcus spp. were significantly increased (P < 0.01 or P < 0.05) in the high fluorine groups II and III. PCR-DGGE analysis showed that the number of DGGE bands, similarity, and Shannon index of ileal and cecal bacteria were markedly reduced in the high fluorine groups II and III from 21 to 42 days. Sequencing analysis revealed that the composition of the intestinal microbiota was altered in the high fluorine groups. In conclusion, dietary fluorine in the range of 800-1200 mg/kg obviously altered the bacterial counts, and the diversity and composition of intestinal microbiota in broiler chickens, a finding which implies that dietary high fluorine can disrupt the natural balance and structure of the intestinal microbiota.

Protective role of selenium in the activities of antioxidant enzymes in piglet splenic lymphocytes exposed to deoxynivalenol

We evaluated the effects of selenium (Se) on antioxidant enzymes of piglet splenic lymphocytes exposed to deoxynivalenol (DON). We measured cell viability, the activities of several antioxidant enzymes, and lactate dehydrogenase (LDH), as well as total antioxidant capacity (T-AOC) and the levels of malonaldehyde (MDA) and hydrogen peroxide (H₂O₂). We found that DON exposure increased the concentrations of LDH, MDA, and H₂O₂ in all experimental groups in a dose-dependent manner, while the concentrations of other antioxidant enzymes were decreased. In Se-pretreated DON-exposed cells, damage to antioxidant enzymes was reduced, especially in the lower-dose DON groups over longer exposure times. These results may indicate that in piglet splenic lymphocytes, Se can alleviate DON-induced damage to antioxidant enzymes by improving glutathione peroxidase activity. Se may function as a potential antioxidative agent to alleviate DON-induced oxidative stress.