Decreased percentages of the peripheral blood T-cell subsets and the serum IL-2 contents in chickens fed on diets excess in fluorine

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.

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.

Suppressive effects of sodium fluoride on cultured splenic lymphocyte proliferation in mice

Fluoride-induced immunotoxicity has been documented in vivo, but limited reports have focused on the effects of fluoride on lymphocytes in vitro. Therefore, we have examined the suppressive effects of sodium fluoride on cultured splenic lymphocytes in mice. CD3+ T lymphocytes, CD19+ B lymphocytes, cytokines, and cell-cycle markers were analyzed through the use of a cell-counting kit, western blot, and flow cytometery. Splenic lymphocytes were isolated from 3-week-old male ICR mice and exposed to sodium fluoride (0, 100, 500, and 1000 μmol/L) for 24 h. The percentages of CD3+, CD3+CD4+, CD3+CD8+ T lymphocytes and CD19+ B lymphocytes were decreased (P<0.05 or P<0.01) in the sodium fluoride-exposed cells. This finding was correlated with the alterations in expression levels of cytokine proteins and with evidence of cell-cycle arrest. Thus, protein expression levels of IL-2, TNF-α, IFN-γ, TGF-β were decreased (P<0.05 or P<0.01), and IL-10 protein expression levels were increased (P<0.05 or P<0.01). The percentage of lymphocyte in G1 phase was significantly increased (P<0.05 or P<0.01), while expression levels of cyclin E/D and CDK2/4 were markedly decreased (P<0.05 or P<0.01). These findings demonstrate that sodium fluoride exposure suppresses splenic lymphocyte proliferation, which is represented by reducing populations and activation of splenic T and B lymphocytes. Alterations of cytokine protein expression and cell cycle arrest are the molecular basis of the sodium fluoride-suppressed splenic lymphocyte proliferation, while reduction of T lymphocytes and B lymphocytes is the explanation of sodium fluoride-decreased splenic immune function in vitro.

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.

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.

Probiotic Lactobacillus johnsonii BS15 Improves Blood Parameters Related to Immunity in Broilers Experimentally Infected with Subclinical Necrotic Enteritis

The probiotic strain Lactobacillus johnsonii BS15 could exert beneficial effects on growth performance, lipid metabolism, and intestinal microflora in healthy broilers and those afflicted with subclinical necrotic enteritis (SNE). In particular, BS15 prevents SNE by enhancing intestinal immunity. To further understand the immune regulatory mechanism of BS15, we evaluated its effects on the overall immunity of broilers by determining blood parameters in healthy and SNE broilers. In this study, two experiments were conducted. Experiment 1 involved a 42-day experimental period and used 450 1-day-old male chicks. The chicks were randomly divided into three groups and fed with a basal diet with or without 1 × 10⁵ or 10⁶ colony-forming units (cfu) BS15/g as feed. Experiment 2 involved a 28-day experimental period and used 180 1-day-old male chicks. The chicks were randomly allotted into three groups and given with or without 1 × 10⁶ cfu BS15/g BS15 as feed. SNE infection was treated in all broilers, except in those in the normal diet group. Antioxidant abilities, immunoglobulins, and cytokines in the serum were assessed. T-lymphocyte subsets in peripheral blood were also determined. The first experiment demonstrated that BS15 enhanced the antioxidant abilities; the serum levels of immunoglobulins, interleukin-2, and interferon-gamma; and CD3⁺CD4⁺ T-lymphocyte percentage in peripheral blood on day 21. However, limited significant changes were observed on day 42. The second experiment revealed that BS15 supplementation positively influenced the antioxidant abilities and increased the serum levels of immunoglobulins and cytokines that were affected by SNE. BS15 also positively affected T-lymphocyte subsets in peripheral blood during SNE infection. These findings suggest that BS15 supplementation may prevent SNE in broilers by improving blood parameters related to immunity and enhancing intestinal immunity. Furthermore, BS15 supplementation can improve blood parameters in healthy broilers, especially at the starter phase.

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 (NaF) induces the splenic apoptosis via endoplasmic reticulum (ER) stress pathway in vivo and in vitro

At present, there are no reports on the relationship between fluoride-induced apoptosis and endoplasmic reticulum (ER) stress (ER stress) in the spleen of human and animals in vivo and in vitro. Therefore, the aim of this study was to define sodium fluoride (NaF)-induced apoptosis mediated by ER stress in the spleen of mice in vivo and in vitro. Apoptosis and expression levels of the ER stress-related proteins were detected by flow cytometry and western blot, respectively. The results showed that NaF treatment increased lymphocytes apoptosis, which was consistent with NaF-caused ER Stress. NaF-caused ER stress was characterized by up-regulating protein expression levels of glucose-regulated protein 78 (BiP) and glucose-regulated protein 94 (GRP94), and by activating unfolded protein response (UPR). The signaling pathway of ER stress-associated apoptosis was activated by up-regulating protein expression levels of cleaved cysteine aspartate specific protease-12 (cleaved caspase-12), growth arrest and DNA damage-inducible gene 153 (Gadd153/CHOP) and phosphorylation of JUN N-terminal kinase (p-JNK). Additionally, our in vitro study found that apoptotic rate was decreased with remarkable down-regulation of the cleaved caspase-12, CHOP, p-JNK after ER stress was inhibited by 4-Phenylbutyric acid (4-PBA) treatment. In conclusion, NaF-induced apoptosis may mediated by ER stress in the spleen.

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.

Effects of feed supplementation with glycine chelate and iron sulfate on selected parameters of cell-mediated immune response in broiler chickens

Because little is known about the impact of chelated (Fe-Gly, Fe-Gly+F) and inorganic (FeSO4, FeSO4+F) iron products on immune response parameters in broiler chickens, the objective of the study was to determine the effects of inorganic and organic forms of iron on selected parameters of the cell-mediated immune response in broiler chickens by assessing the percentage of CD3(+)CD4(+), CD3(+)CD8(+), CD25(+), and MHC Class II lymphocytes, as well as the CD4(+)/CD8(+) ratio and IL-2 concentration in the peripheral blood. The experiments were conducted using 50day-old Ross 308 roosters. The test material was peripheral blood. Flow cytometry was used to determine selected cell-mediated immune response parameters. The results obtained indicate that the use of iron chelates in the diet of broiler chickens may stimulate cellular defense mechanisms. As a result of the experiment an increase was observed in the percentage of Th1, mainly T CD4(+) and T CD8(+). It was also noted that application of chelated iron can increase production of T CD8(+) cytotoxic cells and IL-2, which promotes the body's natural response to developing inflammation. There were no changes in T CD4(+), T CD8(+), T CD25(+) or MHC II lymphocyte subpopulations in the chickens following application of the inorganic form of iron.

Effects of antibacterial peptide on cellular immunity in weaned piglets

The aim of this study was to evaluate the effects of antibacterial peptide (ABP) sufficiency on cellular immune functions by determining the spleen cell cycle and apoptosis, peripheral blood T cell subsets, and T cell proliferation function in weaned piglets. A total of 90 piglets (Duroc × Landrace × Yorkshire) of both sexes were randomly allotted to 5 dietary treatments. Each treatment consisted of 3 replicates with 6 piglets per replicate. The dietary treatments consisted of the negative control (NC; basal diet), positive control (PC; basal diet supplemented with 400 mg/kg Astragalus polysaccharide), and ABP (basal diet mixed with 250, 500, and 1,000 mg/kg ABP). The experimental lasted for 28 d. Two piglets from each replicate were selected randomly for blood samples extraction from the jugular vein to obtain peripheral blood T cell subsets, and T cell proliferation function analysis was performed on d 32, 39, 46, and 53. Two piglets from each replicate were selected and euthanized to observe the spleen cell cycle and apoptosis on d 39 and 53. In ABP-sufficient piglets, the G0/G1 phase of the spleen cell cycle was much lower (P < 0.05) and the S and G2 + M phases and proliferation index (PI) were greater (P < 0.05) than in NC piglets. The percentage of apoptotic cells in the spleen significantly decreased under ABP sufficiency (P < 0.05). The proliferation function of peripheral blood T cells increased (P < 0.05) in ABP-sufficient piglets. Percentages of CD3 (+) and CD3 (+)CD4 (+) ratios (d 39, 46, and 53) and CD4 (+)CD8 (+) ratios (d 32, 39, 46, and 53) increased remarkably (P < 0.05) under ABP sufficiency compared with NC. These results suggest that ABP sufficiency could increase the T cell population and proliferation function of T cells and could induce decreased percentages of apoptotic cells. Overall, the cellular immune function was evidently improved in weaned piglets. We suggest optimal dosages of 500 mg/kg ABP for 4-wk addition and 1,000 mg/kg ABP for 2-wk addition.

Effects of sodium selenite on aflatoxin B1-induced decrease of ileac T cell and the mRNA contents of IL-2, IL-6, and TNF-α in broilers

The aim of this work was to assess the protective effect of sodium selenite on the ileum mucosal immunologic toxicity induced by aflatoxin B1 (AFB1). One hundred and eighty one-day-old healthy male avian broilers were divided into four groups of three replicates and 15 birds per replicate and fed with basal diet (control group), 0.3 mg/kg AFB1 (AFB1 group), 0.4 mg/kg Se (+Se group), and 0.3 mg/kg AFB1+0.4 mg/kg Se (AFB1+Se group), respectively. The ileac T-cell subsets were determined by the methods of flow cytometry (FCM), and the mRNA contents of interleukin-2 (IL-2), interleukin-6(IL-6), and tumor necrosis factor-alpha (TNF-α) by quantitative real-time PCR. Compared with those in control group, the percentages of CD3+, CD3+CD4+, CD3+CD8+ intraepithelial lymphocytes (IELs) and LPLs, the CD4+/CD8+ ratio of IELs, and the mRNA contents of IL-2, IL-6, and TNF-α were decreased in AFB1 group. However, compared with those in AFB1 group, these parameters of AFB1+Se group were increased to be close to those in control group. It was concluded that 0.3 mg/kg AFB1 could reduce the cellular immune function of the ileum mucosa, but 0.4 mg/kg supplemented dietary selenium showed protective effects on AFB1-induced immunologic injury.

Intestinal IgA⁺ cell numbers as well as IgA, IgG, and IgM contents correlate with mucosal humoral immunity of broilers during supplementation with high fluorine in the diets

Fluoride (F), a well-recognized harmful substance, is easily absorbed by the intestinal mucosa. The intestinal mucosal immune system is equipped with unique innate and adaptive defense mechanisms that provide a first line of protection against infectious agents. Meanwhile, immunoglobulins are the major secretory products of the adaptive immune system and their levels can be a strong indicator of a disease or condition. In this study, therefore, we investigated the effects of high dietary fluorine on the numbers of immunoglobulin A-positive (IgA(+)) cells in the lamina propria of intestines (duodenum, jejunum and ileum) by immunohistochemistry as well as on the contents of immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) in the mucosa of intestines (duodenum, jejunum, and ileum) by enzyme-linked immunosorbent assay (ELISA). A total of 280 1-day-old healthy avian broilers were randomly divided into four groups and fed on a corn-soybean basal diet as control diet (fluorine 22.6 mg/kg) or the same basal diet supplemented with 400, 800, and 1,200 mg/kg fluorine (high fluorine groups I, II, and III) in the form of sodium fluoride (NaF) for 42 days. The experimental data showed that the numbers of IgA(+) cells as well as the IgA, IgG, and IgM contents were significantly decreased (P < 0.01 or P < 0.05) in the high fluorine groups II and III when compared with those of the control group. It was concluded that dietary fluorine in the range of 800-1,200 mg/kg significantly reduced the numbers of the IgA(+) cells and the contents of aforementioned immunoglobulins in the intestines (duodenum, jejunum, and ileum) of broilers, which could finally impact the mucosal humoral immune function in the intestines by a way that reduces the lymphocyte population and/or lymphocyte activation.

Decreased IgA+ B cells population and IgA, IgG, IgM contents of the cecal tonsil induced by dietary high fluorine in broilers

Fluoride is an environmental and industrial pollutant that affects various organs in humans and animals. The cecal tonsil is an important component of the mucosal immune system and performs important and unique immune functions. In the present study, we investigated the effects of dietary high fluorine on the quantities of IgA⁺ B cells in the cecal tonsil by immunohistochemistry, and the immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM) contents in the cecal tonsil by ELISA. A total of 280 one-day-old avian broilers were divided into four groups and fed on a corn-soybean basal diet as control diet (fluorine 22.6 mg/kg) or the same diet supplemented with 400, 800 and 1,200 mg/kg fluorine (high fluorine groups I, II and III) in the form of sodium fluoride, respectively, throughout a 42-day experimental period. The results showed that the quantities of IgA⁺ B cells were lower (p < 0.05 or p < 0.01) and the IgA, IgG, and IgM contents were decreased (p < 0.05 or p < 0.01) in high fluorine groups II and III in comparison with those of control group. It was concluded that dietary fluorine, in the 800–1,200 mg/kg range, could reduce the numbers of the IgA⁺ B cells and immunoglobulin contents in the cecal tonsil, implying the local mucosal immune function was ultimately impacted in broilers.

The association between cytokines and intestinal mucosal immunity among broilers fed on diets supplemented with fluorine

Fluorine (F) bioaccumulation has been reported in the organs and tissues of organisms, including intestine. The intestinal mucosa is very important to the immune development. Meanwhile, cytokines are present in the normal intestinal mucosal and play an important role in the immune function. Thus, changes of the cytokine contents are related to the state of intestinal mucosal immunity. In this study, we investigated the changes in contents of cytokines such as interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interferon gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) induced by dietary high F in the mucosa of different parts of intestines (duodenum, jejunum, and ileum) by enzyme-linked immunosorbent assay. A total of 280 one-day-old healthy avian broilers were randomly divided into four groups and fed on a corn-soybean basal diet as control diet (F 22.6 mg/kg) or the same basal diet supplemented with 400, 800, and 1,200 mg F/kg (high F groups I, II, and III) in the form of sodium fluoride for 42 days. The experimental data showed that the contents of IL-2, IL-4, IL-6, IFN-γ, and TNF-α in the intestinal mucosa were significantly decreased in the high F groups II and III when compared with those of the control group from 14 to 42 days of age. It was concluded that dietary F in the range of 800-1,200 mg/kg significantly reduced the contents of aforementioned cytokines in the intestinal mucosa of broilers, which could impact the function of intestinal mucosal immunity through the pathways that decreased the lymphocyte population and/or lymphocyte activation.

Dietary high fluorine induces apoptosis and alters Bcl-2, Bax, and caspase-3 protein expression in the cecal tonsil lymphocytes of broilers

Long-term excessive fluoride intake is known to be toxic and can lead to fluorosis and bone pathologies. However, the cellular mechanisms underlying sodium fluoride-induced cytotoxicity in the cecal tonsil lymphocytes are not well understood. The aims of this study were to investigate the effects of high dietary fluorine on apoptosis and the expression of the Bcl-2, Bax, and caspase-3 in the cecal tonsil lymphocytes of broilers. The broilers were fed on high-fluorine diets containing 0, 400, 800, and 1,200 mg/kg fluorine. As measured by flow cytometry, the percentage of apoptotic lymphocytes was significantly increased in the high-fluorine groups II and III when compared with those in the control group. Meanwhile, immunohistochemical tests showed that the Bcl-2 protein expression decreased, and the Bax and caspase-3 protein expression increased in the high-fluorine groups II and III. In conclusion, dietary fluorine in the range of 800-1,200 mg/kg increased lymphocyte apoptosis in the cecal tonsil of broilers, suggesting that the lymphocyte apoptosis in the cecal tonsil was mediated by direct effects of fluoride on the expression of Bcl-2, Bax, and caspase-3.

Effect of dietary vanadium on the ileac T cells and contents of cytokines in broilers

The purpose of this 42-day study was to examine the effect of dietary vanadium on the ileac T cells and contents of cytokines including interleukin-2 (IL-2), interleukin-6 (IL-6), and interferon-gamma (IFN-γ) in broilers by flow cytometry and enzyme-linked immunosorbent assay. A total of 420 one-day-old avian broilers were divided into six groups (seven replicates in each group and ten broilers in each replicate) and fed on control diet or the same diet supplemented with 5, 15, 30, 45, and 60 mg/kg vanadium in the form of ammonium metavanadate. The results showed that the percentages of CD3(+), CD3(+)CD4(+), and CD3(+)CD8(+) T cells in both ileac lamina propria lymphocytes (LPLs) and intraepithelial lymphocytes (IELs) were significantly lower (P < 0.05 or P < 0.01) in the 45- and 60-mg/kg groups than in the control group from 14 to 42 days of age. The CD4(+)/CD8(+) ratio was increased in ileac LPLs in the 60-mg/kg group at 28 days of age, and in ileac IELs in the 60-mg/kg group at 28 days of age and in the 45-mg/kg group at 42 days of age. Meanwhile, the ileac IL-2, IL-6 contents were decreased (P < 0.05 or P < 0.01) in the 60-mg/kg group from 14 to 42 days of age and in the 45-mg/kg group from 28 to 42 days of age in comparison with those of the control group. It was concluded that dietary vanadium in excess of 30 mg/kg reduced the ileac T cell population and percentages of T cell subsets, and IL-2, IL-6, and IFN-γ contents, implying that the immune function of local intestinal mucosa in broilers could be affected by the dietary vanadium.

Oral vaccination with attenuated Salmonella enterica serovar Typhimurium expressing Cap protein of PCV2 and its immunogenicity in mouse and swine models

Attenuated Salmonella enterica serovar Typhimurium (S. typhimurium) was selected as a transgenic vehicle for the development of oral vaccines against Porcine circovirus type 2 (PCV2). The Cap-encoding gene of PCV2 was amplified by PCR and cloned into expression vector pYA3341. The recombinant plasmid pYA3341-Cap was transformed into attenuated S. typhimurium X4550. BALB/c mice were inoculated orally with various doses of attenuated S. typhimurium X4550/pYA3341-Cap. The bacterium was safe to mice at dose of 2×10(9)cfu and eventually eliminated in the spleen and mesenteric lymph nodes at 4 weeks post-immunization. The flow cytometry analysis showed that the percentage of CD4(+) T cells and CD4(+)/CD8(+) ratio were increased significantly in mice immunized with attenuated S. typhimurium X4550/pYA3341-Cap. Vaccine tests in swine showed that the oral immunization with attenuated S. typhimurium X4550/pYA3341-Cap could elicit significantly higher Cap antibody titers in the treated swine than the control groups. Virus neutralization test showed that serum from the swine treated with attenuated S. typhimurium X4550/pYA3341-Cap had significant levels of neutralization activities. The swine lymphocyte proliferative responses indicated that attenuated S. typhimurium X4550/pYA3341-Cap could induce obvious cellular immune response. An in vivo challenge study showed the swine treated with attenuated S. typhimurium X4550/pYA3341-Cap had significantly lower PCV2-associated lesions and PCV2 viremia than the control groups. The results indicated that attenuated S. typhimurium X4550/pYA3341-Cap can be a potential vaccine against PCV2 infections.

Effect of dietary vanadium on cecal tonsil T cell subsets and IL-2 contents in broilers

The purpose of this 42-day study was to investigate the effects of dietary excess vanadium on intestinal immune function by histopathological observation of cecal tonsil and changes of the cecal tonsil T cell subsets by method of flow cytometry. Four hundred twenty 1-day-old avian broilers were divided into six groups and fed on a corn-soybean basal diet as control diet or the same diet amended to contain 5, 15, 30, 45, and 60 mg/kg vanadium supplied as ammonium metavanadate. In comparison with those of control group, lymphocytes in the lymphatic nodule of cecal tonsil were apparently decreased in 45 and 60 mg/kg groups. The percentage of CD(3)(+) T cells was decreased (p < 0.05) in 45 mg/kg group at 28 and 42 days of age and significantly decreased (p < 0.01) in 60 mg/kg group at 28 and 42 days of age. The percentages of CD(3)(+)CD(4)(+) and CD(3)(+)CD(8)(+) T cells were markedly decreased (p < 0.05 or p < 0.01) in 60 mg/kg group from 14 to 28 days of age and were decreased (p < 0.05) in 45 mg/kg group at 28 and 42 days of age. However, changes of the CD(4)(+)/CD(8)(+) ratio were not significant. Meanwhile, the cecal tonsil interleukin-2 (IL-2) contents were decreased (p < 0.05 or p < 0.01) in 45 and 60 mg/kg groups from 14 to 42 days of age. It was concluded that dietary vanadium in excess of 30 mg/kg reduced the percentages of cecal tonsil T cells subsets and IL-2 contents, and caused cecal tonsil lesions, which impaired cecal tonsil function and impacted the local mucosal immune function of the intestines in broilers.

Effect of dietary high molybdenum on peripheral blood T-cell subsets and serum IL-2 contents in broilers

The objectives of this study were to investigate the effects of dietary high molybdenum (Mo) on immune function by determining changes of the subsets of peripheral blood T-cells and serum interleukin (IL)-2 contents. 300 1-day-old avian broilers were divided into four groups and fed on a corn-soybean basal diet as control diet or the same diet amended to contain 500; 1,000; and 1,500 mg/kg of Mo supplied as sodium molybdate dihydrate. In comparison with those of the control group, the percentages of CD3(+), CD3(+)CD4(+) and CD3(+)CD8(+) were decreased in 1,000 and 1,500 mg/kg of Mo intake groups from 14 days of age to 42 days of age. Also, the serum IL-2 contents were decreased in 1,000 and 1,500 mg/kg of Mo intake groups from 14 days of age to 42 days of age. Histopathologically, hypocellularity appeared in the thymus in 1,000 and 1,500 mg/kg of Mo intake groups. It was concluded that dietary high-Mo (1,000 mg/kg and 1,500 mg/kg) reduced the percentages of peripheral blood T-cell subsets and serum IL-2 contents and caused thymic lesions. The cellular immune function was finally injured in broilers.

Low dietary selenium induce increased apoptotic thymic cells and alter peripheral blood T cell subsets in chicken

The purpose of this 42-day study was to investigate the effects of low selenium (Se) on immune function by determining histopathological changes of thymus, apoptosis of thymic cells, and subpopulation of peripheral blood T cells. One hundred twenty 1-day-old avian broilers were randomly assigned to two groups of 60 each and were fed on a low Se diet (0.0342 mg/kg Se) or a control diet (0.2 mg/kg Se), respectively. The relative weight of thymus was significantly decreased in low Se group from 21 days of age in time-dependent manner when compared with that of control group. Histopathologically, lymphopenia in the cortex and medulla of thymus was observed in low Se group. In comparison with those of control group, the percentage of Annexin-V positive cells was increased, and the percentages of CD3(+) and CD3(+)CD8(+) T cells of the peripheral blood were decreased in low Se group, as measured by flow cytometry. These data suggested that low dietary Se induced histological lesions of thymus, increased apoptosis of thymic cells, and decreased T cell subsets. The cellular immune function was finally impaired in broilers.

Effect of vanadium on the subset and proliferation of peripheral blood T cells, and serum interleukin-2 content in broilers

The purpose of this 42-day study was to investigate the effects of dietary excess vanadium on immune function by determining changes of the subsets and proliferation function of peripheral blood T cells. Four hundred twenty 1-day-old avian broilers were divided into six groups and fed on a corn-soybean basal diet as control diet or the same diet amended to contain 5, 15, 30, 45, and 60 ppm vanadium supplied as ammonium metavanadate. In comparison with those of the control group, the percentages of CD (3) (+) , CD (3) (+) CD (4) (+) , and CD (3) (+) CD (8) (+) were decreased in 45 and 60 ppm groups from 14 to 42 days of age, and the percentages of CD (3) (+) and CD (3) (+) CD (4) (+) were increased in 5 ppm group at 42 days of age. The CD (4) (+) /CD (8) (+) ratio was increased in 45 and 60 ppm groups at 28 days of age. Meanwhile, the proliferation function of peripheral blood T cell were decreased in 30, 45, and 60 ppm groups from 14 to 42 days of age. Also, the serum interleukin-2 contents were decreased in 45 and 60 ppm groups from 14 to 42 days of age and increased in 5 ppm group at 28 days of age. Histopathologically, hypocellularity appeared in the thymus in 45 and 60 ppm groups. It was concluded that dietary vanadium in excess of 30 ppm reduced the percentages of peripheral blood T-cell subsets and the proliferation function and serum interleukin-2 contents. The cellular immune function was finally impaired in broilers.

Lesions of thymus and decreased percentages of the peripheral blood T-cell subsets in chickens fed on diets excess in selenium

Selenium is an essential trace element possessing immune-stimulatory properties. The purpose of this 42-day study was to investigate the effects of excess dietary selenium on cellular immune function by determining morphological changes of thymus and peripheral blood T-cell subset. Three hundred 1-day-old avian broilers were fed on a basic diet (0.2 mg/kg selenium) or the same diet amended to contain 1, 5, 10, 15 mg/kg selenium supplied as sodium selenite ( n = 60/group). Pathological lesions were progressed with the dietary Se level increased. Grossly, the volume of thymus was decreased. Histopathologically, lymphopenia and congestion were observed. Ultrastructurally, mitochondria injury was observed. In comparison with that of control group, 5, 10 and 15 mg/kg dietary Se decreased the percentage of CD3+, CD3+CD4+ and CD3+CD8+ T cells of the peripheral blood, as measured by flow cytometry. The results showed that excess selenium (more than 5 mg/kg) intake could cause lesions of thymus and decrease of T-cell subsets. The cellular immune function was finally impaired in broilers.

Effect of high fluorine on the cell cycle and apoptosis of renal cells in chickens

The experiment was conducted with the objective of evaluating the effect of dietary high fluorine (F) on cell cycle and apoptosis of kidney in chickens by the methods of flow cytometry. Three hundred 1-day-old Avian broilers were divided into four groups and fed on control diet (F 23 mg/kg) and high F diets (400 mg/kg, high F group I; 800 mg/kg, high F group II; 1,200 mg/kg, high F group III) for 6 weeks. As tested by flow cytometry, the percentage of renal cell apoptosis was increased with increasing of dietary F, and it obviously rose in three high F groups when compared with that of control group. Renal cells in G(0)/G(1) phase were much higher, and renal cells in S phase, G(2)+M phase, and proliferation index value were much lower in high F groups I, II, and III than in control group. The results showed that excess dietary F in the range of 400-1,200 mg/kg caused G(0)/G(1) arrest and increased cellular apoptosis in the kidney, which might finally interfere with the excretion and retention of fluoride in chickens.