The mitochondrial and endoplasmic reticulum pathways involved in the apoptosis of bursa of Fabricius cells in broilers exposed to dietary aflatoxin B1

Avian Coronavirus Infectious Bronchitis Virus Activates Mitochondria-Mediated Apoptosis Pathway and Affects Viral Replication by Inducing Reactive Oxygen Species Production in Chicken HD11 Cells

Infectious bronchitis virus (IBV), a coronavirus that causes severe respiratory and gastrointestinal illness in poultry, leads to substantial economic losses. According to earlier research, IBV infection causes chicken macrophage HD11 cells to undergo cell apoptosis. Reactive oxygen species (ROS) and the IBV-activated intrinsic apoptotic signaling pathway were examined in this work. The findings demonstrate that IBV infection causes ROS to accumulate. Moreover, IBV infection decreased the mitochondrial transmembrane potential in HD11 cells, which could be blocked by ROS antioxidants (PDTC and NAC). The two antioxidants significantly affected the expression of Bcl-2 and Bax and further inhibited the activation of caspase-3 and apoptosis in HD11 cells. Additionally, IBV replication was decreased by blocking ROS accumulation. Pretreating HD11 cells with ammonium chloride (NH4Cl) prevented IBV from entering the cells and reduced the oxidative stress which IBV causes. The ability to accumulate ROS was also lost in UV-inactivated IBV. The IBV N protein induces cell apoptosis through the activation of ROS. These findings provide an explanation for the processes of IBV infection in immune cells by indicating that IBV-induced ROS generation triggers cell apoptosis in HD11 cells.

Hesperetin protects hippocampal neurons from the neurotoxicity of Aflatoxin B1 in mice

Aflatoxin B1 (AFB1) is a major food and feed pollutant that endangers public health. Previous studies have shown that exposure to AFB1 causes neurotoxicity in the body. However, the mechanism of neurotoxicity caused by AFB1 is not well understood, and finding a workable and practical method to safeguard animals from AFB1 toxicity is essential. This study confirmed that AFB1 caused endoplasmic reticulum stress (ER stress) and apoptosis in hippocampal neurons using C57BL/6 J mice and HT22 cells as models. In vitro experiments showed that the aryl hydrocarbon receptor (AHR) plays a significant role in the cytotoxicity of AFB1. Finally, we assessed how hesperetin protecting against the neurotoxicity caused by AFB1. Our findings demonstrated that AFB1 increased the levels of BAX and Cleaved-Caspase3 proteins, while decreasing the levels of BCL2 protein in the CA1 and CA3 regions of the hippocampus. The AFB1 increased the expression of AHR and activated nuclear translocation. It also elevated the expression levels of Chop, GRP78, p-IRE1/ Xbp1s, and p-PERK/p-EIF2a. Importantly, we also discovered for the first time that blocking AHR in HT22 cells dramatically reduced the level of ER stress and apoptosis caused by AFB1. In vivo and in vitro studies, supplementation of hesperetin effectively reversed AFB1-induced cytotoxicity. We have demonstrated that hesperetin effectively restored the imbalance in the GSH/GST system in HT22 cells treated with AFB1. Furthermore, we observed that elevated GSH levels facilitated the formation of AFB1-GSH complexes, which enhanced the excretion of AFB1. Therefore, hesperetin improves ER stress-induced apoptosis by reducing AFB1 activation of AHR.

Selenium Protects Follicular Granulosa Cells from Apoptosis Induced by Mercury Through Inhibition of ATF6/CHOP Pathway in Laying Hens

The purpose of this research was to explore the effect of selenium on mercury-mediated apoptosis of follicular granulosa cells in laying hens. Moreover, the ATF6/CHOP pathway was investigated to explore the mechanism in this progress. Hg, Se, and 4-phenyl butyric acid were used alone or in combination to treat the cells. Our results showed that the nuclear in cells became condensate after Hg exposure, while Se addition significantly alleviated this change. Hg exposure significantly induced the apoptosis and the reduction of mitochondrial membrane potential in cells (P < 0.05). Nevertheless, co-treatment of Se significantly inhibited these effects (P < 0.05). Additionally, Hg exposure dramatically elevated the gene expressions of Bax/Bcl-2 (P < 0.05), caspase-3 (P < 0.05), caspase-9 (P < 0.05), protein kinase RNA-like endoplasmic reticulum kinase (P < 0.05), activating transcription factor 6 (P < 0.05), C/EBP homologous protein (CHOP; P < 0.05), inositol-requiring enzyme 1α (P < 0.05), tumor necrosis factor-associated factor 2 (P < 0.05), activating transcription factor 6 (ATF6; P < 0.05), and apoptosis signal-regulating kinase 1 (P < 0.05) in cells, whereas Se addition avoided these changes. The exposure to Hg considerably boosted the expression of ATF6 and CHOP protein (P < 0.05), while Se addition significantly alleviated the above-mentioned enhancements (P < 0.05). In summary, Hg exposure induced apoptosis, which was considerably reduced alleviated by Se addition, which was linked to the ATF6/CHOP pathway in follicular granulosa cells in laying hens.

Effects of Aflatoxin B1 on growth performance, carcass traits, organ index, blood biochemistry and oxidative status in Chinese yellow chickens

In this study, the effects of different levels of aflatoxin B1 (AFB1) on the growth performance, carcass traits, organ index, blood biochemistry, and antioxidant capacity of yellow-feathered broilers were investigated to provide a reference for the application of AFB1-containing feed ingredients. In this test, yellow-feathered broilers were chosen as the research objects and divided into five treatment groups, with seven replicates in each group and 75 broilers in each replicate. The AFB1 concentration in the diets of groups 1 to 5 were 1.5 μg/kg, 15 μg/kg, 30 μg/kg, 45 μg/kg, and 60 μg/kg, respectively. The results showed that when dietary AFB1 levels were greater than 45 μg/kg, the feed conversion ratios of broilers of 1-21, 22-42, and 43-63 days of age increased (P<0.05). When dietary AFB1 levels were 30 μg/kg, liver glutathione peroxidase (GPx) activity was decreased (P<0.05), and serum transaminase (AST) activity was increased (P<0.05). Overall, dietary AFB1 levels had negative effects on growth performance, antioxidant capacity, blood biochemistry, and liver metabolism in yellow-feathered broilers. Based on using growth performance as the effect index, AFB1 levels in the diets of yellow-feathered broilers should not exceed 45 μg/kg. Based on using antioxidant capacity, liver function, and blood biochemistry as effect indexes, AFB1 levels in the diets of yellow-feathered broilers should not exceed 30 μg/kg.

Integrated Profiles of Transcriptome and mRNA m6A Modification Reveal the Intestinal Cytotoxicity of Aflatoxin B1 on HCT116 Cells

Aflatoxin B1 (AFB1) is widely prevalent in foods and animal feeds and is one of the most toxic and carcinogenic aflatoxin subtypes. Existing studies have proved that the intestine is targeted by AFB1, and adverse organic effects have been observed. This study aimed to investigate the relationship between AFB1-induced intestinal toxicity and N6-methyladenosine (m6A) RNA methylation, which involves the post-transcriptional regulation of mRNA expression. The transcriptome-wide m6A methylome and transcriptome profiles in human intestinal cells treated with AFB1 are presented. Methylated RNA immunoprecipitation sequencing and mRNA sequencing were carried out to determine the distinctions in m6A methylation and different genes expressed in AFB1-induced intestinal toxicity. The results showed that there were 2289 overlapping genes of the differentially expressed mRNAs and differentially m6A-methylation-modified mRNAs. After enrichment of the signaling pathways and biological processes, these genes participated in the terms of the cell cycle, endoplasmic reticulum, tight junction, and mitophagy. In conclusion, the study demonstrated that AFB1-induced HCT116 injury was related to the disruptions to the levels of m6A methylation modifications of target genes and the abnormal expression of m6A regulators.

Dietary aflatoxin B1 caused the growth inhibition, and activated oxidative stress and endoplasmic reticulum stress pathway, inducing apoptosis and inflammation in the liver of northern snakehead (Channa argus)

The purpose of this study was to investigate the effects of dietary aflatoxin B₁ (AFB₁) on growth performance and AFB₁ biotransformation, and hepatic oxidative stress, endoplasmic reticulum (ER) stress, apoptosis, and inflammation in northern snakehead (Channa argus). A total of 600 northern snakeheads (7.52 ± 0.02 g) were divided into five groups (three replicates/group) and fed the diets with AFB₁ at concentrations of 0, 50, 100, 200, and 400 ppb for 8 weeks. The results demonstrated that dietary AFB₁ (≥ 200 ppb) reduced FBW, WG, and SGR. 100, 200, and 400 ppb AFB₁ treatment groups significantly decreased the PER, CRP, C3, C4, IgM, and LYS levels in northern snakehead, while FCR was significant increased. Moreover, dietary AFB₁ (100, 200, and 400 ppb) increased cyp1a, cyp1b (except 400 ppb), and cyp3a mRNA expression levels, while reducing the GST enzymatic activity and mRNA expression levels in northern snakehead. Furthermore, AFB₁ (≥ 100 ppb) increased ROS, MDA, and 8-OHdG levels, and grp78, ire1, perk, jnk, chop, and traf2 mRNA expression levels, and decreased SOD, CAT, GSH-Px, and GSH (except 100 ppb) levels and the gene expression levels of cat, gsh-px (except 100 ppb), and Cu/Zn sod. In addition, AFB₁ (100, 200, and 400 ppb) up-regulated the cyt-c, bax, cas-3, and cas-9 mRNA levels in the liver, while down-regulating the bcl-2 expression levels. Meanwhile, the expression levels of nf-κb, tnf-α (except 100 ppb), il-1β, and il-8 in the liver were up-regulated in AFB₁ treatment groups (≥ 100 ppb), while the iκbα mRNA levels were down-regulated. In summary, dietary AFB₁ reduced growth performance and humoral immunity in northern snakehead. Meanwhile, the cyclic occurrence of oxidative stress and ER stress, and induced apoptosis and inflammation, is one of the main reasons for AFB₁-induced liver injury in the northern snakehead, which will provide valuable information and a fresh perspective for further research into AFB₁-induced liver injury in fish.

Research progress in toxicological effects and mechanism of aflatoxin B1 toxin

Fungal contamination of animal feed can severely affect the health of farm animals, and result in considerable economic losses. Certain filamentous fungi or molds produce toxic secondary metabolites known as mycotoxins, of which aflatoxins (AFTs) are considered the most critical dietary risk factor for both humans and animals. AFTs are ubiquitous in the environment, soil, and food crops, and aflatoxin B₁(AFB₁) has been identified by the World Health Organization (WHO) as one of the most potent natural group 1A carcinogen. We reviewed the literature on the toxic effects of AFB₁ in humans and animals along with its toxicokinetic properties. The damage induced by AFB₁ in cells and tissues is mainly achieved through cell cycle arrest and inhibition of cell proliferation, and the induction of apoptosis, oxidative stress, endoplasmic reticulum (ER) stress and autophagy. In addition, numerous coding genes and non-coding RNAs have been identified that regulate AFB₁ toxicity. This review is a summary of the current research on the complexity of AFB₁ toxicity, and provides insights into the molecular mechanisms as well as the phenotypic characteristics.

Evaluation of viral load and expression level of apoptotic genes in selected tissues of two hybrids of commercial broiler chickens challenged with infectious bronchitis virus: a comparative study

BACKGROUND

Infectious bronchitis virus (IBV) causes severe economic losses worldwide. IBV has a broad tissue distribution with different viral loads in different tissues. Additionally, IBV can induce apoptosis in infected cells.

AIMS

The present study aimed to evaluate the role of the genetic background of chickens in viral load and the expression level of apoptotic genes in different tissues of two hybrids of commercial broiler chickens (Ross 308 and Cobb 500) challenged with IBV.

METHODS

Chickens at 21 days of age were nasally challenged with 200 μL of allantoic fluid containing 10⁴ EID₅₀/ml of Iranian variant-2-like IBV (IS/1494). The expression level of apoptotic genes (Fas, FasL, Bax, and Bcl-2) in the tracheal and renal tissues and the amount of viral load in the tracheal, renal, and cloacal swab samples were investigated two, five, and seven days after IBV infection by RT-qPCR assay.

RESULTS

The amount of viral load and apoptotic the expression level of apoptotic genes in the tracheal (two and five days after infection) and renal samples (seven days after infection) were significantly higher in the Ross challenged group than in the Cobb challenged group.Furthermore, no difference was observed in the cloaca viral load on sampling days.

CONCLUSION

To our knowledge, this is the first report that evaluated the role of the chickens' genetic background in the amount of viral load and the expression level of apoptotic genes against IBV. Further studies are needed to investigate the pathogenic characteristics of IBV in Ross 308 and Cobb 500 chickens.

Mycotoxins binder supplementation alleviates aflatoxin B1 toxic effects on the immune response and intestinal barrier function in broilers

This experiment was conducted to evaluate whether a commercial mycotoxins-binder, XL, could effectively attenuate the negative effects of Aflatoxin B₁ (AFB₁) on growth performance, immunological function, and intestinal health in birds. Two hundred forty 1-day-old Arbor Acres broiler chickens were randomly divided into 4 treatments using a 2 × 2 factorial randomized design with 2 levels of dietary mycotoxins binder (0 or 2g /kg) and 2 AFB₁ supplemented levels (0 or 200 μg/kg) from 0 to 42 d. Results showed that AFB₁ exposure impaired growth performance by decreasing BWG in 1–21 d and 1–42 d, decreasing FI in 1–21 d, increasing FCR in 1–21 d and 1–42 d (P < 0.05). Broilers fed AFB₁- contaminated diet impaired the immune function, as evident by decreasing IgA contents, Newcastle disease antibody titers in serum, and sIgA contents of jejunal mucosa at 21 d (P < 0.05). On the other hand, AFB₁ challenge significantly increased the gene expression of proinflammatory factors in spleen at 21 d and liver at 42 d, and significantly decreased claudin-1 expression at 42 d and occludin expression at 21 d, and increased claudin-2 at 21 d in jejunum of broiler chickens (P < 0.05) compared to the basal diet group. Dietary XL supplementation significantly decreased the gene expression of IL-6 in spleen at 21 d and IL-1β in liver at 42 d, cytochrome P450 3A4 (CYP3A4) expression in liver at 21 d of broilers (P < 0.05) compared with the nonsupplemented birds, regardless of AFB₁ challenged or not. Inclusion of 2 g/kg XL increased serum ALB at 42 d, IgM and IgA at 42 d, Newcastle disease antibody titer level at 35 d (P < 0.05). Dietary XL addition enhanced intestinal barrier function by increasing the expression of claudin-1 at 21 d and Occludin at 42 d (P < 0.05) in jejunum. Conclusively, 2 g/kg mycotoxins-binder can relieve the toxic effect of AFB₁ on broilers.

Biocontrol of Aflatoxins Using Non-Aflatoxigenic Aspergillus flavus: A Literature Review

Aflatoxins (AFs) are mycotoxins, predominantly produced by Aspergillus flavus, A. parasiticus, A. nomius, and A. pseudotamarii. AFs are carcinogenic compounds causing liver cancer in humans and animals. Physical and biological factors significantly affect AF production during the pre-and post-harvest time. Several methodologies have been developed to control AF contamination, yet; they are usually expensive and unfriendly to the environment. Consequently, interest in using biocontrol agents has increased, as they are convenient, advanced, and friendly to the environment. Using non-aflatoxigenic strains of A. flavus (AF⁻) as biocontrol agents is the most promising method to control AFs’ contamination in cereal crops. AF⁻ strains cannot produce AFs due to the absence of polyketide synthase genes or genetic mutation. AF⁻ strains competitively exclude the AF⁺ strains in the field, giving an extra advantage to the stored grains. Several microbiological, molecular, and field-based approaches have been used to select a suitable biocontrol agent. The effectiveness of biocontrol agents in controlling AF contamination could reach up to 99.3%. Optimal inoculum rate and a perfect time of application are critical factors influencing the efficacy of biocontrol agents.

Bacillus amyloliquefaciens B10 can alleviate liver apoptosis and oxidative stress induced by aflatoxin B1

Aflatoxin B1 (AFB1) is a mycotoxin often found in food and livestock feed. It can affect human and animal health and is especially damaging to the liver. This study aims to evaluate whether Bacillus amyloliquefaciens (hereafter referred to as B. amyloliquefaciens) B10 can alleviate the toxic effects of AFB1 and, if so, what mechanism is responsible for its action. Specific pathogen-free (SPF) Kunming mice (5-6 weeks old) were divided into four groups (Control, AFB1, B10 strain, and AFB1 + B10 strain) and conducted continuously via gavage for 28 days. Oxidation indices (MDA, T-AOC, SOD, GSH-Px, and CAT) were then measured using their liver tissues and liver coefficient were calculated. Apoptosis was determined using the TUNEL method. Gene expression was determined for Bax, Bcl-2, BIP, CHOP, JNK, Caspase-12, Caspase-9, and Caspase-3, and protein expression was detected for Bax, Bcl-2, and Caspase-3. Our results showed that AFB1 induced the oxidative damage and apoptosis in the livers of mice. However, for mice given B. amyloliquefaciens B10, the biochemical indices, pathological changes, the expressions of genes and proteins related to oxidative stress and apoptosis were significantly reversed. The results indicate that B. amyloliquefaciens B10 antagonizes oxidative damage and apoptosis induced by AFB1 in the livers of mice. The results of this study are of significance for the future use of this strain to reduce the harm of AFB1 to human health and animal reproductive performance.

Methionine alleviates aflatoxinb1-induced broiler chicks embryotoxicity through inhibition of caspase-dependent apoptosis and enhancement of cellular antioxidant status

Practical methods for preventing embryotoxicity in chickens that are caused by aflatoxin-B1 (AFB1) are currently rare. Binding absorbers are commonly used in feeding stuff to reduce laying hens' exposure to off-contaminated diets, thus reducing residue exposure to fertilized eggs. Nonetheless, several adsorbents have been shown to affect the use of nutrients and the absorption of minerals in poultry. Thus, seeking an effective strategy to counter or control embryotoxicity in broiler chicks caused by AFB1 is a problem. A total of 180 embryonated eggs were injected with 36 ng AFB1 with or without 5.90 mg L-methionine (Met) 30 embryonated eggs each, followed by incubation in an incubator until hatching time. The in ovo injection of Met significantly reduced toxicity caused by AFB1 in broiler embryos by enhancing the liver and kidney functions, lipid profiles, and alleviated oxidative stress during the incubation period. Furthermore, the relative gene expressions (SSTR5, TSH-β, Bcl-2, GSH-Px, GST-a, and SOD in the liver) were up-regulated with in ovo injection of AFB1+Met compared to AFB1 alone. Moreover, there was a dowin-regulated trend in Bax, Caspases-3, Caspases-7, Caspases-9, CYP1A1, CYP2H1, and P53 gene expression with in ovo injection of AFB1+Met compared to AFB1 alone. The in ovo injection of Met led to less apoptotic cells in liver tissues. Such results might be necessary for the poultry industry as it is focused on managing the embryotoxicity of AFB1, which affecting poultry production and welfare. Results from this study demonstrated that in ovo Met injection could alleviate AF-induced toxicity in chicken embryos.

Effects of compound probiotics and aflatoxin-degradation enzyme on alleviating aflatoxin-induced cytotoxicity in chicken embryo primary intestinal epithelium, liver and kidney cells

Aflatoxin B₁ (AFB₁) is one of the most dangerous mycotoxins for humans and animals. This study aimed to investigate the effects of compound probiotics (CP), CP supernatant (CPS), AFB₁-degradation enzyme (ADE) on chicken embryo primary intestinal epithelium, liver and kidney cell viabilities, and to determine the functions of CP + ADE (CPADE) or CPS + ADE (CPSADE) for alleviating cytotoxicity induced by AFB₁. The results showed that AFB₁ decreased cell viabilities in dose-dependent and time-dependent manners. The optimal AFB₁ concentrations and reactive time for establishing cell damage models were 200 µg/L AFB₁ and 12 h for intestinal epithelium cells, 40 µg/L and 12 h for liver and kidney cells. Cell viabilities reached 231.58% (p < 0.05) for intestinal epithelium cells with CP addition, 105.29% and 115.84% (p < 0.05) for kidney and liver cells with CPS additions. The further results showed that intestinal epithelium, liver and kidney cell viabilities were significantly decreased to 87.12%, 88.7% and 84.19% (p < 0.05) when the cells were exposed to AFB₁; however, they were increased to 93.49% by CPADE addition, 102.33% and 94.71% by CPSADE additions (p < 0.05). The relative mRNA abundances of IL-6, IL-8, TNF-α, iNOS, NF-κB, NOD1 (except liver cell) and TLR2 in three kinds of primary cells were significantly down-regulated by CPADE or CPSADE addition, compared with single AFB₁ group (p < 0.05), indicating that CPADE or CPSADE addition could alleviate cell cytotoxicity and inflammation induced by AFB₁ exposure through suppressing the activations of NF-κB, iNOS, NOD1 and TLR2 pathways.

Marine algal polysaccharides alleviate aflatoxin B1-induced bursa of Fabricius injury by regulating redox and apoptotic signaling pathway in broilers

Aflatoxin B1 (AFB1) causes toxic effect and leads to organ damage in broilers. Marine algal polysaccharides (MAP) of Enteromorpha prolifera exert multiple biological activities, maybe have a potential detoxification effect on AFB1, but the related research in broilers is extremely rare. Therefore, the purpose of this study was to investigate whether MAPs can alleviate AFB1-induced oxidative damage and apoptosis of bursa of Fabricius in broilers. A total of 216 five-week-old male indigenous yellow-feathered broilers (with average initial body weight 397.35 ± 6.32 g) were randomly allocated to one of three treatments (6 replicates with 12 broilers per replicate), and the trial lasted 4 wk. Experimental groups were followed as basal diet (control group); basal diet mixed with 100 μg/kg AFB1 (AFB1 group, the AFB1 is purified form); basal diet with 100 μg/kg AFB1 + 2,500 mg/kg MAPs (AFB1 + MAPs group). The results showed that the diet with AFB1 significantly decreased the relative weight of bursa of Fabricius (P < 0.05), antioxidant enzymes activities of total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST), and total antioxidation capacity (T-AOC), while increased malondialdehyde (MDA) content (P < 0.05). Besides, compared with AFB1 group, dietary MAPs improved the relative weight of bursa of Fabricius and activities of antioxidant enzymes (T-SOD, GSH-Px, CAT, GST) with decreased MDA contents (P < 0.05). Moreover, the consumption of AFB1 downregulated the mRNA expression of SOD1, SOD2, GSTA3, CAT1, GPX1, GPx3, GSTT1, Nrf2, HO-1, and p38MAPK (P < 0.05). Dietary MAPs upregulated the mRNA expression of SOD2, GSTA3, CAT1, GPX1, GSTT1, p38MAPK, Nrf2, and HO-1 in comparison with AFB1 group (P < 0.05). The histological analysis confirmed restoration of apoptotic cells of bursa of Fabricius (P < 0.01), which seen with MAPs supplemented broilers. Besides, dietary MAPs down-regulated the mRNA expression of caspase-3 and Bax (P < 0.05), while up-regulated the mRNA expression of Bcl-2 (P < 0.05) compared with AFB1 group. In addition, according to protein expression results, dietary MAPs up-regulated the protein expression level of antioxidant and apoptosis-associated proteins (Nrf2, HO-1, p38MAPK, Bcl-2) (P < 0.01), but down-regulated the protein expression level of caspase-3 and Bax (P < 0.01). In conclusion, dietary MAPs alleviated AFB1-induced bursa of Fabricius injury through regulating Nrf2-mediated redox and mitochondrial apoptotic signaling pathway in broilers.

In ovo culturing of turkey (Meleagris gallopavo) ovarian tissue to assess graft viability and maturation of prefollicular germ cells and follicles

Biobanking of turkey ovarian tissue appears to be the most cost-effective method for the long-term preservation of female genetics. However, to ensure the successful transplantation of biobanked ovarian tissue for breed or line revival, the transplantation and development of fresh ovarian tissue must be evaluated. To assess transplantability, ovaries from poults 1 to 15 days posthatch (dph) were cultured in ovo in chicken eggs for 6 d and compared with the equivalent fresh tissue. The viability of cultured ovarian tissue was evaluated visually, whereas the level of late-stage apoptosis was measured via the TUNEL assay. In addition, the diameter and density of prefollicular germ cells and follicles (primordial and primary) were measured to assess maturation. Results showed that all cultured grafts (74/74), on surviving chicken chorioallantoic membrane, were viable with low levels (0.8 ± 0.1%) of late-stage apoptosis. The diameter of prefollicular germ cells in cultured ovaries from poults at 5 and 7 dph were larger (P < 0.002) than that of their preculture counterparts but were not able to reach their in vivo size. No significant follicular growth was observed in ovaries cultured in ovo; however, prefollicular germ cell density was over 4-fold greater in ovaries cultured from 7 dph poults (81,030 ± 17,611/mm³) than in their in vivo counterpart (16,463 ± 6,805/mm³). Interestingly, cultured ovaries from all other ages displayed equal or lower (P ≤ 0.05) prefollicular germ cell densities than their in vivo counterparts. Cultured ovaries from poults at 5 and 7 dph also exhibited an increase (P ≤ 0.05) in follicle density compared with their preculture counterparts; whereas, cultured ovaries from 15 dph poults had decreased densities (P < 0.001) compared with their preculture counterparts. This study demonstrated that, although age of ovarian tissue cultured in ovo did not affect the overall viability, 7 dph ovaries appeared to have a better cellular morphology after culturing in ovo than other ages. In addition, we also demonstrated for the first time that avian follicles can form during tissue culturing in ovo.

Effect of environmental contamination on female and male gametes - A lesson from bovines

Endocrine-disrupting compounds (EDCs) and foodborne contaminants are environmental pollutants that are considered reproductive toxicants due to their deleterious effects on female and male gametes. Among the EDCs, the phthalate plasticizers are of growing concern. In-vivo and in-vitro models indicate that the oocyte is highly sensitive to phthalates. This review summarizes the effects of di(2-ethylhexyl) phthalate and its major metabolite mono(2-ethyhexyl) phthalate (MEHP) on the oocyte. MEHP reduces the proportion of oocytes that fertilize, cleave and develop to the blastocyst stage. This is associated with negative effects on meiotic progression, and disruption of cortical granules, endoplasmic reticulum and mitochondrial reorganization. MEHP alters mitochondrial membrane polarity, increases reactive oxygen species levels and induces alterations in genes associated with oxidative phosphorylation. A carryover effect from the oocyte to the blastocyst is manifested by alterations in the transcriptomic profile of blastocysts developed from MEHP-treated oocytes. Among foodborne contaminants, the pesticide atrazine (ATZ) and the mycotoxin aflatoxin B1 (AFB1) are of high concern. The potential hazards associated with exposure of spermatozoa to these contaminants and their carryover effect to the blastocyst are described. AFB1 and ATZ reduce spermatozoa's viability, as reflected by a high proportion of cells with damaged plasma membrane; induce acrosome reaction, expressed as damage to the acrosomal membrane; and interfere with mitochondrial function, characterized by hyperpolarization of the membrane. ATZ and AFB1-treated spermatozoa show a high proportion of cells with fragmented DNA. Exposure of spermatozoa to AFB1 and ATZ reduces fertilization and cleavage rates, but not that of blastocyst formation. However, fertilization with AFB1- or ATZ-treated spermatozoa impairs transcript expression in the formed blastocysts, implying a carryover effect. Taken together, the review indicates the risk of exposing farm animals to environmental contaminants, and their deleterious effects on female and male gametes and the developing embryo.

Versicolorin A, a precursor in aflatoxins biosynthesis, is a food contaminant toxic for human intestinal cells

Aflatoxin B₁ (AFB₁) is the most potent carcinogen among mycotoxins. Its biosynthesis involves the formation of versicolorin A (VerA), whose chemical structure shares many features with AFB₁. Our data revealed significant levels of VerA in foodstuff from Central Asia and Africa. Given this emerging food risk, it was of prime interest to compare the toxic effects of the two mycotoxins against cells originating from the intestinal tract. We used human colon cell lines (Caco-2, HCT116) to investigate the cytotoxic process induced by the two mycotoxins. Contrary to AFB₁, a low dose of VerA (1 µM) disturbed the expression level of thousands of genes (18 002 genes). We show that the cytotoxic effects of low doses of VerA (1-20 µM) were stronger than the same low doses of AFB₁ in both Caco-2 and HCT116 cell lines. In Caco-2 cells, VerA induced DNA strand breaks that led to apoptosis and reduced DNA replication of dividing cells, consequently inhibiting cell proliferation. Although VerA was able to induce the p53 signaling pathway in p53 wild-type HCT116 cells, its toxicity process did not mainly rely on p53 expression since similar cytotoxic effects were also observed in HCT116 cells that do not express p53. In conclusion, this study provides evidence of the risk of food contamination by VerA and shed light on its toxicological effect on human colon cells.

Critical role of caveolin-1 in aflatoxin B1-induced hepatotoxicity via the regulation of oxidation and autophagy

Aflatoxin B1 (AFB1) is a potent hepatocarcinogen in humans and exposure to AFB1 is known to cause both acute and chronic hepatocellular injury. As the liver is known to be the main target organ of aflatoxin, it is important to identify the key molecules that participate in AFB1-induced hepatotoxicity and to investigate their underlying mechanisms. In this study, the critical role of caveolin-1 in AFB1-induced hepatic cell apoptosis was examined. We found a decrease in cell viability and an increase in oxidation and apoptosis in human hepatocyte L02 cells after AFB1 exposure. In addition, the intracellular expression of caveolin-1 was increased in response to AFB1 treatment. Downregulation of caveolin-1 significantly alleviated AFB1-induced apoptosis and decreased cell viability, whereas overexpression of caveolin-1 reversed these effects. Further functional analysis showed that caveolin-1 participates in AFB1-induced oxidative stress through its interaction with Nrf2, leading to the downregulation of cellular antioxidant enzymes and the promotion of oxidative stress-induced apoptosis. In addition, caveolin-1 was found to regulate AFB1-induced autophagy. This finding was supported by the effect that caveolin-1 deficiency promoted autophagy after AFB1 treatment, leading to the inhibition of apoptosis, whereas overexpression of caveolin-1 inhibited autophagy and accelerated apoptosis. Interestingly, further investigation showed that caveolin-1 participates in AFB1-induced autophagy by regulating the EGFR/PI3K-AKT/mTOR signaling pathway. Taken together, our data reveal that caveolin-1 plays a crucial role in AFB1-induced hepatic cell apoptosis via the regulation of oxidation and autophagy, which provides a potential target for the development of novel treatments to combat AFB1 hepatotoxicity.

Protective effects of Panax notoginseng saponins on PME-Induced nephrotoxicity in mice

Polymyxin E (PME) plays an important role in fighting against Gram-negative bacterial infections; however, it causes nephrotoxicity, which limits its clinical use. The aim of this study was to investigate the protective effects of a plant extract Panax notoginseng saponins (PNS) on PME-induced nephrotoxicity in mice. In vivo studies showed that PNS significantly reduced blood urea nitrogen (BUN), serum creatinine (CRE) and number of apoptotic cells in kidney, as well as renal histopathological damage which increased in the presence of PME, and suppressed PME-induced oxidative stress in kidney, as shown by the up-regulation of superoxide dismutase (SOD) and the down-regulation of malondialdehyde (MDA) levels. Furthermore, PNS inhibited the expression of Bax, while increased the expression of Bcl-2 compared to the PME-treated group. In vitro studies showed that PNS decreased intracellular reactive oxygen species (ROS) and MDA levels, increased glutathione (GSH) levels, and enhanced the activity of SOD and glutathione peroxidase (GSH-Px) in murine renal tubular epithelial cells (TCMK-1 cells). In addition, PNS enhanced cell viability and the expression of Bcl-2, restored the mitochondrial membrane potential, inhibited the expression of Bax, inhibited the activity of caspase-3 and caspase-9, and reduce apoptotic rate in PME-treated TCMK-1 cells. PNS could reduce PME-induced nephrotoxicity. The protective effects could result from inhibition of oxidative stress, and prevention of cell apoptosis via the mitochondrial pathway. These findings highlight the potential of PNS as a safe adjunct for ameliorating the nephrotoxicity.

Protective Effect of Ginsenoside Rg1 on Oxidative Damage Induced by Hydrogen Peroxide in Chicken Splenic Lymphocytes

Previous investigation showed that ginsenoside Rg1 (Rg1) extracted from Panax ginseng C.A. Mey has antioxidative effect on oxidative stress in chickens. The present study was designed to investigate the protective effects of Rg1 on chicken lymphocytes against hydrogen peroxide-induced oxidative stress and the potential mechanisms. Cell viability, apoptotic cells, malondialdehyde, activity of superoxide dismutase, mitochondrial membrane potential, and [Ca²⁺]i concentration were measured, and transcriptome analysis and quantitative real-time polymerase chain reaction were used to investigate the effect of Rg1 on gene expression of the cells. The results showed that treatment of lymphocytes with H₂O₂ induced oxidative stress and apoptosis. However, pretreatment of the cells with Rg1 dramatically enhanced cell viability, reduced apoptotic cells, and decreased oxidative stress induced by H₂O₂. In addition, Rg1 reduced these H₂O₂-dependent decreases in mitochondrial membrane potential and reversed [Ca²⁺]i overload. Transcriptome analysis showed that 323 genes were downregulated and 105 genes were upregulated in Rg1-treated cells. The differentially expressed genes were involved in Toll-like receptors, peroxisome proliferator-activated receptor signaling pathway, and cytokine-cytokine receptor interaction. The present study indicated that Rg1 may act as an antioxidative agent to protect cell damage caused by oxidative stress via regulating expression of genes such as RELT, EDA2R, and TLR4.

Harmful Effects and Control Strategies of Aflatoxin B₁ Produced by Aspergillus flavus and Aspergillus parasiticus Strains on Poultry: Review

The presence of aflatoxin B₁ (AFB₁) in poultry diets decreases the hatchability, hatchling weight, growth rate, meat and egg production, meat and egg quality, vaccination efficiency, as well as impairing the feed conversion ratio and increasing the susceptibility of birds to disease and mortality. AFB₁ is transferred from poultry feed to eggs, meat, and other edible parts, representing a threat to the health of consumers because AFB₁ is carcinogenic and implicated in human liver cancer. This review considers how AFB₁ produced by Aspergillus flavus and Aspergillus parasiticus strains can affect the immune system, antioxidant defense system, digestive system, and reproductive system in poultry, as well as its effects on productivity and reproductive performance. Nutritional factors can offset the effects of AFB₁ in poultry and, thus, it is necessary to identify and select suitable additives to address the problems caused by AFB₁ in poultry.

Dicerandrol B: a natural xanthone dimer induces apoptosis in cervical cancer HeLa cells through the endoplasmic reticulum stress and mitochondrial damage

Background

Dicerandrol B is a natural antitumor agent that can be isolated from the endophytic fungus, Phomopsis sp. The present study investigated the effects of dicerandrol B on human cervical cancer HeLa cells.

Materials and methods

In this study, dicerandrol B was identified by electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. We used MTT to detect the cell viability. Flow cytometry was used to analyze the apoptosis and cell cycle. Western blot was used to examine the expression of related proteins.

Results

Dicerandrol B was isolated from the endophytic fungus Phomopsis sp. The MTT assay and flow cytometry showed that dicerandrol B significantly inhibited HeLa cell viability and induced G2/M cell cycle arrest. Western blot analysis demonstrated that dicerandrol B increased the levels of GRP78, ubiquitin, cleaved PARP, and Bax protein, decreased the levels of PARP and Bcl-2 protein, and caused an increase in the Bax/Bcl-2 ratio in HeLa cells. Dicerandrol B increased the production of ROS in HeLa cells, which was attenuated by the antioxidant N-acetyl-l-cysteine.

Conclusion

These findings suggest that dicerandrol B induces apoptosis in human HeLa cells, possibly through the endoplasmic reticulum stress and mitochondrial apoptotic pathways. This suggests that dicerandrol B possesses strong anticancer activity in cervical cancer and provides insight into the underlying mechanisms.

Water-soluble substances of wheat: a potential preventer of aflatoxin B1-induced liver damage in broilers

Aflatoxin B1 (AFB1) is very harmful for broiler production and public health. The water-soluble castoff in gluten production, i.e., the water-soluble substances of wheat (WSW) that contains 14% pentosan has positive effect on animal nutrient absorption, immunity, and antioxidation. Our study aims to investigate the preventive effects of WSW against AFB1-induced broiler liver injury. One day-old Arbor Acres broilers were randomly separated to 4 groups and were, respectively, fed with control diet, diet with 5 mg/kg AFB1 standard, diet with 5 mg/kg AFB1 standard and 214 ml/kg WSW, and diet with 214 ml/kg WSW continuously for 28 d. The histopathological, ultra-structural, and serological changes were tested to evaluate liver damage. The hallmarks of hepatocellular autophagy, apoptosis, and inflammation were measured by Western Blot and real-time polymerase chain reaction. The content of AFB1 in chicken liver was detected with an ultra-high performance liquid chromatography linked with the fluorescence detection method. The results showed that (i) WSW restored AFB1-induced changes in serum biochemical parameters, and ameliorated histomorphological changes in hepatocytes, (ii) WSW reduced the content of AFB1 in chicken liver, (iii) WSW alleviated AFB1-induced autophagy inhibition by up-regulating hepatic LC3, beclin-1, and down-regulating hepatic mTOR and cytoplasmic P53 expressions, (iv) WSW alleviated AFB1-induced hepatocellular apoptosis via inhibiting pro-apoptotic gene expression (nuclear P53, Caspase3, Bax), and promoting anti-apoptotic gene expression (bcl-2), (v) WSW feeding ameliorated AFB1-induced liver inflammation via impeding TLR4/NF-${{\bf \kappa }}$B and IL-1/NF-${{\bf \kappa }}$B signaling pathways, down-regulating pro-inflammatory cytokines (IL-1${{\bf \beta }}$, IL-6, and IL-8), and markedly up-regulating anti-inflammatory genes (IL-10 and HO-1). Conclusively, WSW is a potential preventer of AFB1-induced broiler liver damage by reducing the AFB1 content in liver, accelerating hepatocellular autophagy and inhibiting hepatocytes apoptosis and liver inflammation.

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.

Clinicopathological and prognostic significance of C/EBP homologous protein (CHOP) in advanced gastric cancer

BACKGROUND

Few studies have reported the clinical and prognostic significance of C/EBP homologous protein (CHOP) in advanced gastric cancer (GC). Therefore, the present study investigated the expression of CHOP in advanced GC patients to determine its potential prognostic role.

METHODS

The levels of CHOP in 95 patients with advanced GC and adjacent non-cancerous tissues were evaluated by qRT-PCR, western blot and immunohistochemistry. Furthermore, the association of CHOP expression with clinicopathological parameters and prognosis of advanced GC patients was analyzed.

RESULTS

The levels of CHOP were down-regulated in advanced GC compared with non-cancerous tissues (P<0.01). In addition, high CHOP expression more frequently occurred in advanced GC tissues with depth of invasion of T_1-2 (P < 0.01), lower clinical stage (TNM Ⅰ-Ⅱ stage) (P<0.05) and without lymph node metastasis (P<0.05). No significant difference was observed between the expression of CHOP and age, gender, tumor size, lesion site and differentiation (P>0.05). The Kaplan-Meier survival analyses showed that the overall survival rate of advanced GC patients with positive CHOP expression was significantly higher than that of patients with negative CHOP expression (P<0.01). Univariate and multivariate Cox proportional hazards models revealed that low CHOP expression (OR = 0.314, 95%CI: 0.176～0.794, P = 0.003) was an independent factor for poor overall survival in advanced GC patients.

CONCLUSION

Low expression of CHOP predicts the poor prognosis of advanced GC patients, and CHOP may be a prognostic biomarker for patients with advanced GC.

Subchronic arsenism-induced oxidative stress and inflammation contribute to apoptosis through mitochondrial and death receptor dependent pathways in chicken immune organs

In many organ dysfunctions, arsenic and its compounds are well known to induce apoptosis by the mitochondria and death receptor apoptotic pathways in liver and airway. However, it is less reported that which signaling pathways contribute to excessive apoptosis of chicken immune organs, a major target of toxic metals biotransformation, which suffer from subchronic arsenism. In this study, we investigated whether the mitochondria or death receptor apoptotic pathways activated in the immune organs (spleen, thymus and bursa of Fabricius) of one-day-old male Hy-line chickens exposed to arsenic trioxide (As₂O₃), which were fed on diets supplemented with 0, 0.625, 1.25 and 2.5 mg/kg BW of As₂O₃ for 30, 60 and 90 days. We found that (1) Oxidative damage and inflammatory response were confirmed in the immune organs of chickens fed on As₂O₃ diet. (2) Subchronic arsenism induced typical apoptotic changes in ultrastructure. (3) TdT-mediated dUTP Nick-End Labeling (TUNEL) showed that the number of apoptotic cells significantly increased under subchronic arsenism. (4) As₂O₃-induced apoptosis of immune organs involved in mitochondrial pathway (decrease of B-cell lymphoma-2 (Bcl-2) and increase of protein 53 (p53), Bcl-2 Associated X Protein (Bax), caspase-9, caspase-3) and death receptor pathway (increase of factor associated suicide (Fas) and caspase-8). In conclusion, this work is the first to demonstrate that the activation of mitochondria and death receptor apoptosis pathways can lead to excessive apoptosis in immune organs of chickens, which suffer from subchronic arsenism, meanwhile, oxidative stress as well as subsequent inflammatory is a crucial driver of apoptosis.

The molecular mechanism of cell cycle arrest in the Bursa of Fabricius in chick exposed to Aflatoxin B 1

Aflatoxin B₁ shows potent hepatotoxic, carcinogenic, genotoxic, immunotoxic potential in humans and many species of animals. The aim of this study was to clarify the underlying mechanism of G₀G₁ phase and G₂M phase arrest of cell cycle in the bursa of Fabricius in broilers exposed to dietary AFB₁. 144 one-day-old healthy Cobb broilers were randomly divided into two groups and fed on control diet and 0.6 mg·Kg⁻¹ AFB₁ diet for 3 weeks. Histological observation showed that AFB₁ induced the increase of nuclear debris and vacuoles in lymphoid follicle of BF. Results of flow cytometry studies showed that bursal cells arrested in G₂M phase at 7 days of age and blocked in G₀G₁ phase at 14 and 21 days of age following exposure to AFB₁. The qRT-PCR analysis indicated that cell cycle arrested in G₂M phase via ATM-Chk2-cdc25-cyclin B/cdc2 pathway, and blocked in G₀G₁ phase through ATM-Chk2-cdc25-cyclin D/CDK6 pathway and ATM-Chk2-p21-cyclin D/CDK6 route. In a word, our results provided new insights that AFB₁ diet induced G₂M and G₀G₁ phase blockage of BF cells in different periods, and different pathways were activated in different arrested cell cycle phase.

Construction of a Bcl-2-shRNA expression vector and its effect on the mitochondrial apoptosis pathway in SW982 cells

Apoptosis is considered to serve an important role in the pathogenesis of rheumatoid arthritis. The aim of the present study was to construct Bcl-2-short hairpin (sh)RNA expression vectors and transfect them into human synovial sarcoma SW982 cells, in order to screen for an effective interference sequence and analyze the effects of this interference on the expression levels of Bcl-2 and other molecules associated with the mitochondrial apoptosis pathway. Three different shRNAs (Bcl-2-sh1, 2 and 3) were designed according to the human Bcl-2 mRNA target sequence and were transformed into competent DH5α Escherichia coli cells following the construction of an expression vector, which was then transfected into SW982 cells. SW982 cells were grouped into a control group (transfected with a negative control shRNA), and Bcl-2-sh1, Bcl-2-sh2 and Bcl-2-sh3 groups (transfected with Bcl-2-sh1, 2 and 3, respectively). The expression levels of Bcl-2 mRNA were detected using reverse transcription-quantitative PCR (RT-qPCR). Bcl-2-sh1 was identified as the most effective shRNA sequence for interference, and was used for subsequent experiments. The mRNA and protein expression levels of Bcl-2, Bax, CytC and Caspase-3 were detected in SW982 cells by RT-qPCR and western blotting at various time-points (48 and 72 h) following transfection with Bcl-2-sh1, in order to observe the effectiveness of this interference. Compared with the control group, the expression levels of Bcl-2 were decreased, while those of Bax, CytC and Caspase-3 were increased in Bcl-2-sh1-transfected cells (P<0.01). The interference effect was greater at 48 h than at 72 h. In summary, an effective shRNA sequence (Bcl-2-sh1) targeting the Bcl-2 gene was identified from three candidates, and was demonstrated to significantly interfere with the expression of Bcl-2, Bax, CytC and Caspase-3 when transfected into SW982 cells. The interference effect of Bcl-2-sh1 was more pronounced at 48 h than at 72 h post-transfection.

Aflatoxin B1 affects apoptosis and expression of death receptor and endoplasmic reticulum molecules in chicken spleen

Aflatoxin B₁ (AFB₁) is a natural product of the Aspergillus genus of molds, which grow on several foodstuffs stored in hot moist conditions, and is among the most potent hepatocarcinogens and immunosuppression presently known. The latter was related to the up-regulated apoptosis of immune organs. However, the effect of expression of death receptor and endoplasmic reticulum molecules in AFB₁-induced apoptosis of chicken splenocytes was largely unknown. The objective of this study was to investigate this unknown field. One hundred and forty four one-day-old chickens were randomly divided into control group (0 mg/kg AFB₁) and AFB₁ group (0.6 mg/kg AFB₁), respectively and fed with AFB₁ for 21 days. Histological observation demonstrated that AFB₁ caused slight congestion and lymphocytic depletion in the spleen. TUNEL and flow cytometry assays showed the excessive apoptosis of splenocytes provoked by AFB₁. Moreover, quantitative real-time PCR analysis revealed that AFB₁ induced the elevated mRNA expression of Fas, FasL, TNF-α, TNF-R₁, Caspase-3, Caspase-8, Caspase-10, Grp78 and Grp94 in the spleen. These findings suggested that AFB₁ could lead the excessive apoptosis and alter the expression of death receptor and endoplasmic reticulum molecules in chicken spleen.

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.

Infectious Bronchitis Virus Infection Induces Apoptosis during Replication in Chicken Macrophage HD11 Cells

Avian infectious bronchitis has caused huge economic losses in the poultry industry. Previous studies have reported that infectious bronchitis virus (IBV) infection can produce cytopathic effects (CPE) and apoptosis in some mammalian cells and primary cells. However, there is little research on IBV-induced immune cell apoptosis. In this study, chicken macrophage HD11 cells were established as a cellular model that is permissive to IBV infection. Then, IBV-induced apoptosis was observed through a cell viability assay, morphological changes, and flow cytometry. The activity of caspases, the inhibitory efficacy of caspase-inhibitors and the expression of apoptotic genes further suggested the activation of apoptosis through both intrinsic and extrinsic pathways in IBV-infected HD11 cells. Additionally, ammonium chloride (NH₄Cl) pretreated HD11 cells blocked IBV from entering cells and inhibited IBV-induced apoptosis. UV-inactivated IBV also lost the ability of apoptosis induction. IBV replication was increased by blocking caspase activation. This study presents a chicken macrophage cell line that will enable further analysis of IBV infection and offers novel insights into the mechanisms of IBV-induced apoptosis in immune cells.

Down-regulation of microRNA-155 promotes selenium deficiency-induced apoptosis by tumor necrosis factor receptor superfamily member 1B in the broiler spleen

The aim of this work was to explore the microRNA profile and the effect of microRNA-155 on apoptosis in the spleen of selenium-deficient broilers. We replicated the splenic-apoptotic model in selenium-deficient broilers. In vitro, microRNA-155 oligonucleotides were transfected into lymphocytes and subsequently treated with H₂O₂. We observed that selenium deficiency altered the microRNA profile and decreased the expression of microRNA-155 in the broiler spleens. Tumor necrosis factor receptor superfamily member 1B was verified as a target of microRNA-155 in the splenocytes. Morphological changes, increased levels of tumor necrosis factor receptor superfamily member 1B, c-Jun N-terminal kinase, Bak, Bax, Cyt-c, caspase9 and caspase3 and decreased levels of Bcl-2 demonstrated that selenium deficiency induced apoptosis in the spleen tissues. In vitro, microRNA-155 m inhibited the levels of ROS and reduced apoptosis compared with microRNA-155i in the lymphocytes. These results suggested that the reduced levels of microRNA-155 due to selenium deficiency could promote oxidative stress-induced apoptosis by increased tumor necrosis factor receptor superfamily member 1B in splenic cells.

Pathological Impairment, Cell Cycle Arrest and Apoptosis of Thymus and Bursa of Fabricius Induced by Aflatoxin-Contaminated Corn in Broilers

This study aimed to evaluate the comparative effects of aflatoxin-contaminated corn on the thymus and bursa of Fabricius (BF) in chickens by detecting histopathological lesions, cell cycle phase distribution and apoptosis. A total of 900 COBB500 male broilers were randomly allocated into five groups. The experiment lasted for six weeks and the five dietary treatments consisted of uncontaminated corn (control), 25% contaminated corn, 50% contaminated corn, 75% contaminated corn and 100% contaminated corn groups. The gross changes showed the decreased size of the thymus and BF, as well as the pale color of the BF in the broilers after aflatoxin contaminated diet exposure. There were more nuclear debris in the thymus and BF of birds in the 50%, 75%, and 100% contaminated corn groups, but the pathological impairments of the BF were more obvious than those of the thymus, which showed as more obvious lymphocyte depletion and the proliferation of reticulocytes and fibroblasts. At 21 days of age, the percentage of thymocytes and BF cells in the G2M phase was increased in a dose-dependent manner in the four AFB-contaminated corn groups. However, at 42 days of age, dietary AFB₁ induced cell cycle perturbation at the G0G1 phase in thymocytes, but at the G2M phase in BF cells. The increased percentage of apoptotic cells in the thymus and BF were similarly observed in the AFB groups. According to these results, the severity of histopathological lesions may be correlated with the different sensitivity of the two central immune organs when exposed to AFB; different arrested cell cycle phases suggest that different mechanisms may be involved in the lesions of the thymus and BF, which need to be further researched.