Deoxynivalenol-induced cytokines and related genes in concanavalin A-stimulated primary chicken splenic lymphocytes

New Insights into Decabromodiphenyl Ether-Induced Splenic Injury in Chickens: Involvement of ROS-Mediated Endoplasmic Reticulum Stress Pathway Triggering Autophagy and Apoptosis

Decabromodiphenyl ether (BDE-209) is a widely used brominated flame retardant that can easily detach from materials and enter into feed and foodstuffs, posing a serious risk to human and animal health and food safety of animal origin. However, the immunotoxic effects of BDE-209 on the avian spleen and the exact mechanism of the toxicity remain unknown. Therefore, we established an experimental model of BDE-209-exposed chickens and a positive control model of cyclophosphamide-induced immunosuppression in vivo and treated MDCC-MSB-1 cells and chicken splenic primary lymphocytes with BDE-209 in vitro. The results showed that BDE-209 treatment caused morphological and structural abnormalities in the chicken spleens. Mechanistically, indicators related to oxidative stress, endoplasmic reticulum stress (ERS), autophagy, and apoptosis were significantly altered by BDE-209 exposure in both the spleen and lymphocytes, but the use of the N-acetylcysteine or the 4-phenylbutyric acid significantly reversed these changes. In addition, BDE-209 exposure decreased the spleen antimicrobial peptide and immunoglobulin gene expression. In conclusion, the present research revealed that BDE-209 exposure enhanced lymphocyte autophagy and apoptosis in chicken spleen via the ROS-mediated ERS pathway. This signaling cascade regulatory relationship not only opens up a new avenue for studying BDE-209 immunotoxicity but also provides important insights into preventing BDE-209 hazards to animal health.

Protective effects of melatonin on deoxynivalenol-induced oxidative stress and autophagy in IPEC-J2 cells

This study explored protective effects of melatonin (MEL) on deoxynivalenol (DON)-induced toxicity in porcine jejunum epithelial cells (IPEC-J2). Cells were preexposed to MEL and then exposed to DON to detect cell viability, apoptosis, and oxidative stress indicators. Compared to DON treatment, pretreatment with MEL significantly increased cell proliferation. (P < 0.01), intracellular catalase (CAT) and superoxide dismutase (SOD) levels (P < 0.05), decreased apoptosis and oxidative stress, and significantly attenuated the inflammatory response. RNA-seq analysis revealed that MEL protects IPEC-J2 from the adverse effects of DON by affecting the expression of tight junction and autophagy pathway-related genes. Similarly, further experiments revealed that MEL partly prevented DON-induced disruption of intestinal barrier function and decreased autophagy induced by DON via activation of the AKT/mTOR pathway. In conclusion, these results demonstrated the preventive properties of MEL against DON-induced cell damage by activating the antioxidant system and Inhibition of autophagy.

Effects of aflatoxin B1 on growth performance, antioxidant status, immune response, and pro-inflammatory cytokine mRNA expression in ISA chicks

The research evaluated the effects of Aflatoxin B1 on growth performance, antioxidant status, immune response, and pro-inflammatory cytokine mRNA expression in ISA chicks. In total, 240 7-day-old ISA chicks were randomly assigned to four treatment groups. The control group comprised chicks fed a basal diet. The aflatoxin (AFB₁)-treatment groups (T1, T2, and T3) comprised chicks fed the basal diet supplemented with AFB₁ at concentrations of 5, 8, and 10 μg/kg, respectively. The growth performance, antioxidant status, immune responses, and pro-inflammatory cytokine mRNA expression in all groups were measured. In the T1 treatment group (receiving the lowest AFB₁ dose), a reduction in the Newcastle disease virus antibody (NDV-Ab) titer, and increases in interleukin 2 (IL-2), IL-6, and interferon γ (IFN-γ) mRNA levels were observed on days 21 and 42 (P < 0.05). Treatment with the higher AFB₁ doses (groups T2 and T3) reduced the chicks' growth performance on days 21 and 42, measured as reductions in body weight (BW) and average daily gain (ADG) compared with the control group. In the T2 and T3 groups, the total antioxidant capacity (T-AOC), glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities, serum immunoglobulin A (IgA) and IgG levels, and IL-2, IL-6, and IFN-γ levels were also lower than in the control group. On days 21 and 42, these two groups also showed increased malondialdehyde (MDA) content, higher feed to gain ratio (F/G), and higher IL-2, IL-6, and IFN-γ mRNA levels than the control group (P < 0.05). The T2 and T3 groups also showed reduced T-AOC, NDV-Ab titer, IL-2 content, and GPx-1 mRNA levels on days 21 and 42 (P < 0.05), increased IL-6 and IFN-γ mRNA levels on day 21, and increased F/G and MDA content on day 42 (P < 0.05) compared with group (T1). Increased MDA content and IL-6 mRNA levels in the liver and ileum were observed in group T3 compared with group T2 on day 21, and lower IgM and IL-6 levels were observed on days 21 and 42 (P < 0.05). In conclusion, our data showed that AFB₁ exposure resulted in dose-dependent oxidative and inflammatory damage, immunosuppression, and a decline in the growth performance of chicks.

Dihydroartemisinin alleviates deoxynivalenol induced liver apoptosis and inflammation in piglets

Deoxynivalenol (DON) is one of the mycotoxins that contaminate cereals and feed, thereby endangering human and animal health. Dihydroartemisinin (DHA), a derivative of artemisinin, has anti-inflammatory and antioxidant functions in addition to anti-malaria and anti-cancer. The purpose of this study was to investigate the effects of DHA on alleviating liver apoptosis and inflammation induced by DON in piglets. The experimental design followed a 2 (normal diet and DON-contaminated diet) × 2 (with and without supplementation of DHA) factorial arrangement. 36 weaned piglets were subjected to a 21-day experiment. Results showed that DON increased ALT activity, the levels of TNF-α, IL-1β and IL-2, and reduced the levels of total protein (TP) and albumin (ALB) in the serum. However, DHA decreased the levels of TNF-α, IL-1β and IL-2, and increased the levels of TP and ALB. Also, DON decreased glutathione (GSH) content and catalase (CAT) activity, and increased methane dicarboxylic aldehyde (MDA) content. But GSH content was increased by DHA. In addition, DHA decreased DON-induced increase in apoptosis rate of hepatocytes. Furthermore, DON activated death receptor pathway to promote apoptosis by up-regulating the protein expression of FasL and caspase-3, and the mRNA expression of FasL, TNFR1, caspase-8, Bid, Bax, CYC and caspase-3. However, DHA reduced caspase-3 protein expression, as well as the mRNA expression of FADD, Bid, Bax, CYC and caspase-3. Besides, DON also activated TNF/NF-κB pathway to induce an inflammatory response by up-regulating TNF-α protein expression, and the mRNA expression of TNFR1, RIP1, IKKβ, IκBα, IL-1β and IL-8. Nevertheless, DHA reduced the mRNA expression of RIP1, IκBα, NF-κB, IL-1β and IL-6, and the protein expression of TNF-α and NF-κB. In conclusion, DHA improved DON-induced negative effects on serum biochemical parameters and inflammatory cytokine levels, hepatic antioxidant capacity, hepatic apoptosis and inflammation.

Subclinical Doses of Combined Fumonisins and Deoxynivalenol Predispose Clostridium perfringens–Inoculated Broilers to Necrotic Enteritis

Fumonisins (FB) and deoxynivalenol (DON) are mycotoxins which may predispose broiler chickens to necrotic enteritis (NE). The objective of this study was to identify the effects of subclinical doses of combined FB and DON on NE. A total of 480 day-old male broiler chicks were divided into four treatment groups; 1) control group (basal diet + Clostridium perfringens); 2) necrotic enteritis group (basal diet + Eimeria maxima + C. perfringens); 3) FB + DON group (basal diet + 3 mg/kg FB + 4 mg/kg DON + C. perfringens); and 4) FB + DON + NE group (basal diet + 3 mg/kg FB + 4 mg/kg DON + E. maxima + C. perfringens). Birds in NE and FB + DON + NE groups received 2.5 × 10³E. maxima on day 14. All birds were inoculated with C. perfringens on days 19, 20, and 21. On day 35, birds in the NE, FB + DON, and FB + DON + NE groups had 242, 84, and 339 g lower BWG and a 19-, 2-, and 22-point increase in FCR respectively, than in the control group. Subclinical doses of FB + DON increased (p < 0.05) the NE lesion scores compared to the control group on day 21. On day 21, birds in the NE, FB + DON, and FB + DON + NE groups had increased (p < 0.05) serum FITC-D, lower (p < 0.05) jejunal tight junction protein mRNA, and increased (p < 0.05) cecal tonsil IL-1 mRNA compared to control group. On day 21, birds in the NE group had decreased (p < 0.05) villi height to crypt depth ratio compared to the control group and the presence of FB + DON in NE-induced birds further decreased the villi height to crypt depth ratio. Birds in the NE, FB + DON, and FB + DON + NE groups had increased (p < 0.05) C. perfringens, lower (p < 0.05) Lactobacillus loads in the cecal content, and a lower (p < 0.05) CD8⁺: CD4⁺ cell ratio in the cecal tonsils compared to the control group. It can be concluded that subclinical doses of combined FB and DON predispose C. perfringens-inoculated birds to NE, and the presence of FB + DON in NE-induced birds exacerbated the severity of NE.

Ginsenoside Rb1 prevents deoxynivalenol-induced immune injury via alleviating oxidative stress and apoptosis in mice

Deoxynivalenol (DON) is considered to be a grave threat to humans and animals. Ginsenoside Rb1 (Rb1) has been reported for its antioxidant potential and medicinal properties. However, the shielding effects of Rb1 and the precise molecular mechanisms against DON-induced immunotoxicity in mice have not been reported yet. In the present research, 4-weeks old healthy C57BL/6 mice were randomly assigned into four experimental groups (n = 12), viz., CON, DON 3 mg/kg BW, Rb1 50 mg/kg BW and DON 3 mg/kg + Rb1 50 mg/kg BW (DON + Rb1). Feed intake and body weight gain were monitored during the entire experiment (15 d). Our results demonstrated that Rb1 markedly increased the ADG (30%) and ADFI (25.10%) of mice compared with DON group. Furthermore, Rb1 alleviated the DON-induced immune injury by relieving the splenic histopathological alteration, enhancing the T-lymphocytes subsets (CD4⁺, CD8⁺), the levels of cytokines (IL-2, IL-6, IFN-γ, and TNF-α), as well as production of immunoglobulins (IgA, IgM, and IgG). Moreover, Rb1 ameliorated DON-inflicted oxidative stress by reducing the ROS, MDA and H₂O₂ contents and boosting the antioxidant defense system (T-AOC, T-SOD, CAT, and GSH-Px). Additionally, Rb1 significantly reversed the DON-induced excessive splenic apoptosis via modulating the mitochondria-mediated apoptosis pathway in mice, depicting the decreased percentage of splenocyte apoptotic cells by 26.65%, down-regulated the mRNA abundance of Bax, caspase-3, caspase-9, and protein expression of Bax, cleaved caspase-3, and Cyt-c. Simultaneously, Rb1 markedly rescued both Bcl-2 mRNA and protein expression levels. Taken together, Rb1 mitigates DON-induced immune injury by suppressing the oxidative damage and regulating the mitochondria-mediated apoptosis pathway in mice. Conclusively, our current research provides an insight into the preventive mechanism of Rb1 against DON-induced immune injury in mice and thus, presents a scientific baseline for the therapeutic application of Rb1.

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.

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.

Trichothecenes: immunomodulatory effects, mechanisms, and anti-cancer potential

Paradoxically, trichothecenes have both immunosuppressive and immunostimulatory effects. The underlying mechanisms have not been fully explored. Early studies show that dose, exposure timing, and the time at which immune function is assessed influence whether trichothecenes act in an immunosuppressive or immunostimulatory fashion. Recent studies suggest that the immunomodulatory function of trichothecenes is also actively shaped by competing cell-survival and death-signaling pathways. Autophagy may also promote trichothecene immunosuppression, although the mechanism may be complicated. Moreover, trichothecenes may generate an "immune evasion" milieu that allows pathogens to escape host and vaccine immune defenses. Some trichothecenes, especially macrocyclic trichothecenes, also potently kill cancer cells. T-2 toxin conjugated with anti-cancer monoclonal antibodies significantly suppresses the growth of thymoma EL-4 cells and colon cancer cells. The type B trichothecene diacetoxyscirpenol specifically inhibits the tumor-promoting factor HIF-1 in cancer cells under hypoxic conditions. Trichothecin markedly inhibits the growth of multiple cancer cells with constitutively activated NF-κB. The type D macrocyclic toxin Verrucarin A is also a promising therapeutic candidate for leukemia, breast cancer, prostate cancer, and pancreatic cancer. The anti-cancer activities of trichothecenes have not been comprehensively summarized. Here, we first summarize the data on the immunomodulatory effects of trichothecenes and discuss recent studies that shed light on the underlying cellular and molecular mechanisms. These mechanisms include autophagy and major signaling pathways and their crosstalk. Second, the anti-cancer potential of trichothecenes and the underlying mechanisms will be discussed. We hope that this review will show how trichothecene bioactivities can be exploited to generate therapies against pathogens and cancer.

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.

Establishment of SV40 large T antigen-immortalized bovine liver sinusoidal cell lines and their immunological responses to deoxynivalenol and lipopolysaccharide

Immortalized bovine sinusoidal cell lines provide useful tools to study the immunological responses in the liver to the gastrointestinal tract-derived toxic substances, which may cause systemic symptoms in the affected livestock. Here, we established two immortalized bovine liver sinusoidal cell lines, endothelial-like B46, and myofibroblast-like A26, from primary cultures of bovine liver cells by the transfection with SV40 large T antigen. The pro-inflammatory cytokine responses in these cell lines to deoxynivalenol (DON) and lipopolysaccharide (LPS) were then compared to those in the primary bovine Kupffer cells (BKC). BKC were highly responsive to LPS, showing increased levels of IL-1α, IL-1β, IL-6, and TNF-α mRNA 3 h after stimulation. DON induced similar pro-inflammatory cytokine responses in BKC, except for IL-6. The endothelial B46 cells exhibited upregulation of IL-1α, IL-1β, and IL-6 3 h after stimulation by LPS. In contrast to the stimulation by LPS, B46 had relatively low pro-inflammatory cytokine responses to DON, except for IL-1α, which was moderately induced at 3 h and increased at 24 h after stimulation. The myofibroblast-like A26 cells exhibited low responses in the induction of pro-inflammatory cytokines to LPS or DON; however, the expression of IL-6 was significantly observed 3 h after DON stimulation. Our results suggest that bovine liver sinusoidal cells have distinctive pro-inflammatory cytokine responses against harmful substances, and these immune responses might determine the consequence of systemic inflammations in the diseased animal.

Effect of Different Selenium Supplementation Levels on Oxidative Stress, Cytokines, and Immunotoxicity in Chicken Thymus

This study assessed the effects of different selenium (Se) supplementation levels on oxidative stress, cytokines, and immunotoxicity in chicken thymus. A total of 180 laying hens (1 day old; Mianyang, China) were randomly divided into 4 groups (n = 45). The chickens were maintained either on a basic diet (control group) containing 0.2 mg/kg Se, a low-supplemented diet containing 5 mg/kg Se, a medium-supplemented diet containing 10 mg/kg Se, or a high-supplemented diet containing 15 mg/kg Se for 15, 30, and 45 days, respectively. Over the entire experimental period, serum and thymus samples were collected and used for the detection of the experimental index. The results indicated that the antioxidative enzyme activities and messenger RNA (mRNA) levels of antioxidative enzymes, IFN-γ and IL-2 in the thymus, and the content of IFN-γ and IL-2 in the serum of excessive-Se-treated chickens at all time points (except for the 5 mg/kg Se supplement group at 15 days) were significantly decreased (P < 0.05) compared to the corresponding control groups. Interestingly, a significantly increase (P < 0.05) in the content of IFN-γ was observed in the serum and thymus in the 5 mg/kg Se supplement group at 15 and 30 days compared to the corresponding control groups. In histopathological examination, the thymus tissue from excessive-Se-treated chickens revealed different degrees of cortex drop, incrassation of the medulla, and degeneration of the reticular cells. These results suggested that the excessive Se could result in a decrease in immunity, an increase in oxidative damage, and a series of clinical pathology changes, such as cortex drop, incrassation of the medulla, and degeneration of the reticular cells.

Interleukin-10 neutralizing antibody for detection of intestinal luminal levels and as a dietary additive in Eimeria challenged broiler chicks

Interleukin-10 (IL-10) mRNA levels are increased within intestinal mucosa after Eimeria infection. IL-10 apical receptor presence on enterocytes suggests IL-10 is secreted into the intestinal lumen. Increased IL-10 has been shown to be central to the pathogenesis of numerous intracellular pathogens; we hypothesize luminal secretion of IL-10 enables Eimeria spp. infection in chickens. This study examines intestine luminal IL-10 levels and performance in broilers challenged with Eimeria when fed an anti-IL-10 antibody. Chicks were fed a diet (1 to 21 d) with control or anti-IL-10 antibody (0.34 g egg yolk antibody powder/Kg diet) with a saline or 10× dose of Advent coccidiosis vaccine on d 3. One chick per pen was euthanized on days 2, 4, 7, 10, 13, 16, and 19 post-challenge, bled, and intestines were collected for luminal fluid IL-10 concentrations. Body weight and feed intake were measured on d 21, and oocyst shedding was assessed on d 7 post-challenge. A significant Eimeria × antibody interaction on d 21 body weight (P < 0.05) showed chicks fed control antibody, but not anti-IL-10, had significant reductions in body weight when challenged with Eimeria spp. Oocyst shedding was increased with Eimeria challenge, but dietary antibody had no effect. Plasma carotenoid levels were reduced in Eimeria challenged chicks 4, 7, 10, and 16 days post-challenge compared to unchallenged chicks. Lack of an Eimeria × antibody interaction showed anti-IL-10 was not protective against Eimeria-induced decreases in plasma carotenoids. Eimeria challenge increased intestine luminal IL-10 on days 4 and 7 post-challenge in the cecum and jejunum, respectively, compared to unchallenged. Dietary anti-IL-10 decreased luminal IL-10 in the ileum on day 2 post-challenge when compared to control antibody fed chicks. No interaction between Eimeria challenge and antibody was observed on intestine luminal contents of IL-10, suggesting anti-IL-10 was ineffective at preventing increased Eimeria-induced luminal IL-10. In conclusion, Eimeria challenge increased intestinal luminal IL-10 and anti-IL-10 was effective at preventing Eimeria-induced decreased body weight, however the mechanism anti-IL-10 antibody protects body weight during Eimeria challenge remains unknown.