Amuc Prevents Liver Inflammation and Oxidative Stress in Mice Challenged with Salmonella Typhimurium.

BACKGROUND: Salmonella typhimurium is a pathogen that causes gastroenteritis in humans and animals. Amuc_1100 (hereafter called Amuc), the outer membrane protein of Akkermansia muciniphila, alleviates metabolic disorders and maintains immune homeostasis. OBJECTIVE: This study was conducted to determine whether there is a protective effect of Amuc administration. METHODS: Male 6-wk-old C57BL6J mice were randomly allocated into 4 groups: CON (control), Amuc (gavaged with Amuc, 100 µg/d for 14 d), ST (oral administration of 1.0 × 106 CFU S. typhimurium on day 7), and ST + Amuc (Amuc supplementation for 14 d, S. typhimurium administration on day 7). Serum and tissue samples were collected 14 d after treatment. Histological damage, inflammatory cell infiltration, apoptosis, and protein levels of genes associated with inflammation and antioxidant stress were analyzed. Data were analyzed by 2-way ANOVA and Duncan's multiple comparisons using SPSS software. RESULTS: The ST group mice had 17.1% lower body weight, 1.3-3.6-fold greater organ index (organ weight/body weight for organs including the liver and spleen), 10-fold greater liver damage score, and 3.4-10.1-fold enhanced aspartate transaminase, alanine transaminase, and myeloperoxidase activities, and malondialdehyde and hydrogen peroxide concentrations compared with controls (P < 0.05). The S. typhimurium-induced abnormalities were prevented by Amuc supplementation. Furthermore, the ST + Amuc group mice had 1.44-1.89-fold lower mRNA levels of proinflammatory cytokines (interleukin [Il]6, Il1b, and tumor necrosis factor-α) and chemokines (chemokine ligand [Ccl]2, Ccl3, and Ccl8) and 27.1%-68.5% lower levels of inflammation-related proteins in the liver than ST group mice (P < 0.05). CONCLUSIONS: Amuc treatment prevents S. typhimurium-induced liver damage partly through the toll-like receptor (TLR)2/TLR4/myeloid differentiation factor 88 and nuclear factor-κB signaling as well as nuclear factor erythroid-2 related factor signaling pathways. Thus, Amuc supplementation may be effective in treating liver injury in S. typhimurium-challenged mice.

Roles of stress response-related signaling and its contribution to the toxicity of zearalenone in mammals.

Zearalenone (ZEA) is a mycotoxin frequently found in cereal crops and cereal-derived foodstuffs worldwide. It affects plant productivity, and is also a serious hazard to humans and animals if being exposed to food/feed contaminated by ZEA. Studies over the last decade have shown that the toxicity of ZEA in animals is mainly mediated by the various stress responses, such as endoplasmic reticulum (ER) stress, oxidative stress, and others. Accumulating evidence shows that oxidative stress and ER stress signaling are actively implicated in and contributes to the pathophysiology of various diseases. Biochemically, the deleterious effects of ZEA are associated with apoptosis, DNA damage, and lipid peroxidation by regulating the expression of genes implicated in these biological processes. Despite these findings, the underlying mechanisms responsible for these alterations remain unclear. This review summarized the characteristics, metabolism, toxicity and the deleterious effects of ZEA exposure in various tissues of animals. Stress response signaling implicated in the toxicity as well as potential therapeutic options with the ability to reduce the deleterious effects of ZEA in animals were highlighted and discussed.

Protective Effects of Cinnamaldehyde on the Inflammatory Response, Oxidative Stress, and Apoptosis in Liver of Salmonella typhimurium-Challenged Mice.

Salmonella typhimurium infection is associated with gastrointestinal disorder and cellular injury in the liver of both humans and animals. Cinnamaldehyde, the main component of essential oil from cinnamon, has been reported to have anti-inflammatory, anti-oxidative, and anti-apoptotic effects. However, it remains unknown whether cinnamaldehyde can alleviate Salmonella typhimurium infection-induced liver injury in mice. In the present study, we found that cinnamaldehyde attenuated Salmonella typhimurium-induced body weight loss, the increase of organ (liver and spleen) indexes, hepatocyte apoptosis, and the mortality rate in mice. Further study showed that cinnamaldehyde significantly alleviated Salmonella typhimurium-induced liver injury as shown by activities of alanine transaminase, aspartate transaminase, and myeloperoxidase, as well as malondialdehyde. The increased mRNA level of pro-inflammatory cytokines (IL-1ß, IL-6, TNF-α, and IFN-γ) and chemokines (CCL2 and CCL3) induced by Salmonella typhimurium were significantly abolished by cinnamaldehyde supplementation. These alterations were associated with a regulatory effect of cinnamaldehyde on TLR2, TLR4, and MyD88. 16S rDNA sequence analysis showed that Salmonella typhimurium infection led to upregulation of the abundances of genera Akkermansia, Bacteroides, Alistipes, Muribaculum, and Prevotellaceae UCG-001, and downregulation of the abundances of genera Lactobacillus, Enterorhabdus, and Eggerthellaceae (unclassified). These alterations were reversed by cinnamaldehyde supplementation. In conclusion, cinnamaldehyde attenuated the inflammatory response, oxidative stress, and apoptosis in the liver of Salmonella typhimurium-infected mice. Supplementation of cinnamaldehyde might be a preventive strategy to alleviate liver injury caused by Salmonella typhimurium infection in humans and animals.

Effects of varying wheat levels on growth performance, intestinal barrier, and cecal microbiota of broilers.

Introduction: The study aimed to investigate the potential effects of varying wheat levels in broiler diets on growth performance, intestinal barrier, and cecal microbiota. Methods: Day-old male broilers were fed the same diet until 10 d of age. Then they were randomly assigned to 1) the low-level wheat group, where inclusion of 15.0% and 25.0% wheat in the grower and finisher diet, respectively, 2) the medium-level wheat group with 30.0% and 40.0% of wheat in the grower and finisher periods; and 3) the high-level wheat dietary group, in which the grower and finisher diets contained 55.77% and 62.38% of wheat, respectively. Results: Dietary treatments unaffected the body weight at 39 d, whereas incorporating high wheat in diets significantly increased the feed intake and reduced the feed conversion ratio from 10 to 39 d (p < 0.05). Except for increased phosphorus digestibility in the high wheat group, dietary treatments had no significant effect on the apparent digestibility of dry matter, crude protein, and ether extract. Meanwhile, the broilers that consumed the medium and high content of wheat presented a higher villus height and the ratio of villus height to crypt depth than those fed the low-level wheat birds. Feeding the medium-level wheat enhanced ileal integrity and depressed the expression of proinflammatory cytokines in the ileum. The addition of high levels of wheat reduced the Chao1 index and the abundance of Lactobacillaceae, Bacteroidaceae, and Ruminococcacea in cecal content, which probably decreased the metabolism of histidine, sulfur-containing amino acids, and the biosynthesis of lysine. Discussion: These results support the medium-level wheat diet improved intestinal barrier function and had no deleterious effects on the growth performance of broiler; dietary inclusion of high wheat reduced the feed conversion rate, which might be associated with the disturbed gut microbiota and decreased metabolism of amino acids.

Alteration of growth performance, glycolipid metabolism, and bone characteristics of broiler chickens in response to different inclusion levels of dietary wheat.

Objective: The aim of this study was to evaluate the effects of different levels of wheat inclusion on growth performance, glycolipid metabolism, and tibial properties of broiler chickens. Methods: A total of 480 1-d-old male broiler chickens were initially fed identical starter diets until d 10. Subsequently, they were divided into 3 treatments consisting of 8 replicates with 20 birds per replicate, i.e., 1) low-level wheat addition group, with wheat ratios of 15% and 25% during the grower and finisher periods, respectively; 2) medium-level wheat inclusion group, incorporating 30% and 40% wheat in the grower and finisher diets, respectively; and 3) high-level wheat addition group, containing 55.8% and 62.4% wheat in the grower and finisher diets, until d 39. Results: When compared to the low- and medium-level wheat diet, the high-level wheat inclusion in the diet increased feed intake and reduced the feed conversion ratio (both p<0.01), which was accompanied by a longer jejunum (p=0.031). Meanwhile, the high-level addition of wheat displayed a decreased abundance of Ruminococcin, Bacteroidetes, and Lactobacillus than the low-wheat group. With the increase of the proportion of wheat treatment, the contents of cholesterol, triglyceride, and high-density lipoprotein cholesterol were elevated in serum, whereas the concentration of serum C-terminal cross-linked telopeptide of type I collagen, a bone resorption marker, was decreased. In addition, the diet with medium and high levels of wheat improved the yield load of tibia, along with comparable bone dimension and weight. Conclusion: The medium- and high-level wheat additions increased serum glycolipid deposition and enhanced tibial mechanical properties, whereas the high-level wheat diet compromised the growth performance of broiler chickens, which might be associated with the alteration of gut microbiota.

Replacement of Corn with Different Levels of Wheat Impacted the Growth Performance, Intestinal Development, and Cecal Microbiota of Broilers.

Replacing corn with different levels of wheat in the iso-energy and -protein diet of broilers and the impacts on growth performance and intestinal homeostasis of broilers under the condition of supplying the multienzyme complex were evaluated in this study. A total of 480 10-day-old male broilers were assigned randomly to the low-level wheat group (15% wheat and 35.18% corn), the medium-level wheat group (30% and 22.27%), and the high-level wheat group (55.77% wheat without corn) until 21 d. The different levels of wheat supplementation did not affect hepatic function, serum glycolipid profile, or bone turnover. The replacement of corn with 55% wheat in the diet of broilers increased the body weight at 21 d and feed intake during 10 to 21 d (both p < 0.05), with a comparable feed conversion ratio. Compared with the low-wheat group, the dietary addition of medium or high wheat levels notably increased the ratio of villus height to crypt depth in the duodenum (p < 0.05) and the ileal villus height (p < 0.05). Meanwhile, the supplementation of medium and high wheat in the diet increased the proportion of Bacteroidetes, and a diet with high wheat proportion elevated the content of Firmicutes when compared to the low-level wheat group (both p < 0.05). In addition, the diet containing 30-55% wheat enhanced the anti-inflammatory capability in both the ileum and the serum. These findings suggest that the replacement of corn with 55% wheat in the diet improved the growth performance of 21-day-old broilers, which might be linked to the alteration in intestinal morphology and cecal microbiota.

Enhancing aggression in Henan gamecocks via augmentation of serotonergic-dopaminergic signaling and attenuation of neuroimmune response.

Animal aggression is one of the most conserved behaviors. Excessive and inappropriate aggression was a serious social concern across species. After long-term selection under strict stress conditions, Henan gamecock serves as a good model for studying aggressive behavior. In this research, we constructed a Henan game chicken backcross population containing 25% Rhode Island Red (RIR), and conducted brain transcriptomics and serum metabolomics analyses on Henan gamecock (HGR) through its comparison with its female encounters (HGH) and the male backcross birds (BGR). The study revealed that seven differential metabolites in serum and 172 differentially expressed genes in the brain were commonly shared in both HGR vs. HGH and HGR vs. BGR comparisons. They exhibited the same patterns of modulation in Henan gamecocks, following either HGH < HGR > BGR or HGH > HGR < BGR style. Therein, some neurological genes involving in serotonergic and dopaminergic signaling were upregulated, while the levels of many genes related with neuro-immune function were decreased in Henan gamecock. In addition, many unknown genes specifically or highly expressed in the brain of the Henan gamecock were identified. These genes are potentially key candidates for enhancing the bird's aggression. Multi-omics joint analysis revealed that tyrosine metabolism and neuroactive ligand-receptor interaction were commonly affected. Overall, our results propose that the aggressiveness of Henan gamecocks can be heightened by the activation of the serotonergic-dopaminergic metabolic process in the brain, which concurrently impairs the neuroimmune system. Further research is needed to identify the function of these unknown genes on the bird's aggressive behavior.

Benzo[a]pyrene induces epithelial tight junction disruption and apoptosis via inhibiting the initiation of autophagy in intestinal porcine epithelial cells.

Ingestion of food contaminated with benzo[a]pyrene (B[a]P) poses health risks to animals and humans. However, the toxicity of B[a]P exposure on the intestinal barrier function and underlying mechanisms remain obscure. In the present study, intestinal porcine epithelial cells (IPEC-1) were challenged with different doses of B[a]P and its deleterious effects were determined. We found that B[a]P exposure led to impaired intestinal tight junction function as evidenced by reduced transepithelial electric resistance, increased permeability, and downregulated intestinal tight junction protein levels. Further study demonstrated that B[a]P treatment induced cell cycle arrest, and resulted in oxidative damage-related apoptosis in IPEC-1 cells. Intriguingly, we observed an inhibition of autophagy and an activation of unfolded protein response (UPR) in B[a]P-challenged cells, when compared with controls. To investigate the role of autophagy on B[a]P-induced epithelial tight junction disruption and apoptosis, cells were cotreated with B[a]P and rapamycin, and rapamycin dramatically improved intestinal tight junction and reduced apoptosis, indicating a protective effect of autophagy for the cells in response to B[a]P treatment. We also explored the role of UPR in B[a]P-induced cellular damage by using 4-phenylbutyric acid, an antagonist of UPR. Interestingly, B[a]P-induced apoptosis and dysfunction of the intestinal tight junction were exacerbated by 4-phenylbutyric acid, and the 4-phenylbutyric acid didn't ameliorate the inhibitory effects of B[a]P on microtubule-associated protein 1 light chain 3 (LC3-II) and lysosomal-associated membrane protein 2 (LAMP2) in IPEC-1 cells. These novel findings provided herein indicated that B[a]P induces intestinal epithelial tight junction disruption and apoptotic cell death via inhibiting autophagy in IPEC-1 cells.

Zearalenone induces apoptosis and autophagy by regulating endoplasmic reticulum stress signalling in porcine trophectoderm cells.

Zearalenone (ZEA), a mycotoxin produced mainly by fungi belonging to Fusarium species in foods and feeds, causes a serious hazard to humans and animals. Numerous studies have revealed that ingesting ZEA can disrupt the reproductive function and impair the reproductive process in animals. This experiment was to investigate the toxicological effect and the mechanism of ZEA exposure on reproduction in pigs during early stages of pregnancy. In the present study, we treated with 0 to 80 µmol/L ZEA for 12 or 24 h in trophoblast ectoderm (pTr) cells. The results showed that ZEA had significantly decreased cell proliferation (P < 0.05), which was accompanied by DNA damage-related cell cycle arrest at G2/M phase, activation of the apoptosis and endoplasmic reticulum (ER) stress, as well as impairment of barrier function (P < 0.05). Western blot analysis and transmission electron microscopy (TEM) showed that exposure to ZEA can activation of autophagy in pTr cells. Importantly, pretreatment with chloroquine (CQ) or 3-methyladenine (3-MA) led to increased apoptosis in pTr cells. Interestingly, pTr cells pretreated with 4-phenylbutyric acid (4-PBA), an inhibitor of ER stress, resulted in reduced cell death in pTr cells, indicating a critical role for ER stress in the activation of autophagy. In conclusion, these results reveal that ZEA-triggered ER stress is critical for the cell fate decision of pTr cells during early porcine embryonic development. Application of small molecules with ability of blocking ER stress might be therapeutic option to reduce the deleterious effect of ZEA in pregnant animals.

l-Proline improves the cytoplasmic maturation of mouse oocyte by regulating glutathione-related redox homeostasis.

Recent studies have shown that l-proline (proline) is an antioxidant to protect cells from oxidative stress in vivo and in vitro. Glutathione (GSH) is a major cellular redox regulator involved in controlling redox balance and is regarded as one of the key indices to predict the cytoplasmic maturation of oocytes. The objectives of this study are to investigate the effect of proline on the developmental potential of mouse oocytes and to determine the role of gap junctional communication (GJC) on intraoocyte GSH concentration during in vitro maturation (IVM). Compared with control (0 mmol/L), 0.5 mmol/L proline supplementation enhanced rates of activated oocytes, 2-cell and 4-cell embryos, and blastocysts. Furthermore, 0.25 and 0.5 mmol/L proline supplementation markedly upregulated mRNA expression of glutamate-cysteine ligase catalytic subunit (GCLC) and glutamate-cysteine ligase modifier subunit (GCLM) in oocytes and cumulus cells, enhanced GSH concentration in oocytes, and reduced reactive oxygen species (ROS) level in oocytes. Interestingly, carbenoxolone disodium salt (CBX) treatment reduced GSH concentration in oocytes and the rate of early embryo development without proline incubation. Notably, CBX-triggered reduction in the rates of the number of 2-cell and 4-cell embryos and blastocysts were rescued by 0.5 mmol/L proline supplementation. Collectively, these results indicate a novel functional role of proline in oocyte cytoplasmic maturation and regulation of glutathione-related redox homeostasis.

Association between intestinal microbiota and inflammatory bowel disease.

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), has emerged as a global disease with high incidence, long duration, devastating clinical symptoms, and low curability (relapsing immune response and barrier function defects). Mounting studies have been performed to investigate its pathogenesis to provide an ever-expanding arsenal of therapeutic options, while the precise etiology of IBD is not completely understood yet. Recent advances in high-throughput sequencing methods and animal models have provided new insights into the association between intestinal microbiota and IBD. In general, dysbiosis characterized by an imbalanced microbiota has been widely recognized as a pathology of IBD. However, intestinal microbiota alterations represent the cause or result of IBD process remains unclear. Therefore, more evidences are needed to identify the precise role of intestinal microbiota in the pathogenesis of IBD. Herein, this review aims to outline the current knowledge of commonly used, chemically induced, and infectious mouse models, gut microbiota alteration and how it contributes to IBD, and dysregulated metabolite production links to IBD pathogenesis.

4-Phenylbutyric acid alleviates 3-acetyldeoxynivalenol-induced immune cells response by inhibiting endoplasmic reticulum stress in mouse spleen.

3-Acetyldeoxynivalenol (3-Ac-DON), an acetylated derivative of deoxynivalenol (DON), is contaminated grains and grain-based products in general and been harmful to human and animal health. However, the damage effects and regulatory mechanisms to the host immune system have not been well explored. In the present study, our results revealed that 3-Ac-DON significantly decreased spleen index, elevated MPO activity, upregulated mRNA and protein levels of IL-1α, IL-1ß, IL-6, IL-17A, TNF-α, M-CSF, G-CSF, CCL2, IFN-ß, and IL-10 in the spleen and serum. Interestingly, 4-phenylbutyric acid (4-PBA), an inhibitor of endoplasmic reticulum (ER) stress, largely abolished the above adverse effects. Importantly, 3-Ac-DON enhanced the mRNA abundances of ER stress-related indicators, such as BIP, IRE1A, ATF6, XBP-1, EIF2A, ATF4, and CHOP, which were abolished by 4-PBA, indicating the inhibiting effects of ER stress by 4-PBA in the spleen. Furthermore, 3-Ac-DON reshaped the populations of innate immune cells (neutrophils, macrophages, dendritic cells, natural killer cells) and adaptive immune cells (T lymphocytes, helper T cells, suppressor T cells, and B lymphocytes) in the peripheral blood and spleen lymphocytes. In conclusion, our studies demonstrated that the adverse effects of 3-Ac-DON on immune cells response could be implemented by ER stress and the ameliorative effect of 4-PBA.

α-Ketoglutarate Restores Intestinal Barrier Function through Promoting Intestinal Stem Cells-Mediated Epithelial Regeneration in Colitis.

This study investigated the preventive effects of α-ketoglutarate (α-KG, in the form of sodium salt) on a Citrobacter rodentium (CR)-induced colitis and explored potential mechanisms. The results demonstrated that CR caused body weight loss and colon length shortening, which were abrogated by the α-KG administration. The colon length of mice in the α-KG plus CR group was significantly higher than that of mice in the CR group (6.9 ± 0.59 (mean ± SD) vs 6.1 ± 0.55; P < 0.05). This beneficial effect was associated with regulating endoplasmic reticulum (ER) stress signaling. In addition, small intestinal organoids generated from intestinal crypts of mice were exposed to α-KG in the presence of TNF-α or IWR-1 to assess stem cell activity in vitro. The results demonstrated that TNF-α exposure decreased the viability of organoids and impaired barrier function by suppressing Wnt signaling, which was abolished by α-KG. Interestingly, the protective effect of α-KG on intestinal barrier function was abrogated by the inhibitor of Wnt signaling in the intestinal organoids. Taken together, α-KG restored barrier function by regulating ER stress and activating Wnt/ß-catenin-medicated intestinal stem cell proliferation and differentiation.

Alpha-Ketoglutarate Attenuates Colitis in Mice by Increasing Lactobacillus Abundance and Regulating Stem Cell Proliferation via Wnt-Hippo Signaling.

SCOPE: Inflammatory bowel disease is an inflammatory gastrointestinal disorder associated with intestinal barrier damage, cell proliferation disorder, and dysbiosis of the intestinal microbiota. It remains unknown whether alpha-ketoglutarate (α-KG) can alleviate colitis in mice. METHODS AND RESULTS: Six-week-old male C57BL/6 mice supplemented with or without 0.5% α-KG (delivered in the form of sodium salt) are subjected to drinking water or 2.5% DSS to induce colitis. The results show that α-KG administration is attenuated the severity of colitis, as is indicated by reduced body-weight loss, colon shortening and colonic hyperplasia, and repressed proinflammatory cytokine secretion in DSS-challenged mice. Additionally, DSS-induced increases in malondialdehyde (MDA) and hydrogen peroxide (H2 O2 ), and decreases in glutathione (GSH) levels are attenuated by α-KG administration. Further study shows that the protective effect of α-KG is associated with restoring gut barrier integrity by enhancing the expression of tight junction proteins, increasing Lactobacillus levels, and regulating gut hyperplasia by the Wnt-Hippo signaling pathway in DSS-induced colitis. CONCLUSION: Collectively, the data provided herein demonstrate that α-KG administration is attenuated mucosal inflammation, barrier dysfunction, and gut microflora dysbiosis. This beneficial effect is associated with increased Lactobacillus levels and regulated colon hyperplasia by the Wnt-Hippo signaling pathway.

Docosahexaenoic Acid Ester of Phloridzin Reduces Inflammation and Insulin Resistance via AMPK.

BACKGROUND: Docosahexaenoic acid-acylated phloridzin (PZ-DHA), a novel polyphenol fatty acid ester derivative, is synthesized through an acylation reaction of phloridzin (PZ) and docosahexaenoic acid (DHA). PZ-DHA is more stable than DHA and exhibits higher cellular uptake and bioavailability than PZ. OBJECTIVE: The study aims to investigate the effects of PZ-DHA on insulin resistance in the skeletal muscle and the related mechanisms; we used palmitic acid (PA)-treated C2C12 myotubes as an insulin resistance model. RESULTS: We found that PZ-DHA increased the activity of AMP-activated protein kinase (AMPK) and improved glucose uptake and mitochondrial function in an AMPK-dependent manner in untreated C2C12 myotubes. PZ-DHA treatment of the myotubes reversed PA-induced insulin resistance; this was indicated by increases in glucose uptake and the expression of membrane glucose transporter 4 (Glut4) and phosphorylated Akt. Moreover, PZ-DHA treatment reversed PA-induced inflammation and oxidative stress. These effects of PZ-DHA were mediated by AMPK. Furthermore, the increase in AMPK activity, improvement in insulin resistance, and decrease in inflammatory and oxidative responses after PZ-DHA treatment diminished upon co-treatment with a liver kinase B1 (LKB1) inhibitor, suggesting that PZ-DHA improved AMPK activity by regulating its upstream kinase, LKB1. CONCLUSION: The effects of PZ-DHA on insulin resistance in C2C12 myotubes may be mediated by the LKB1- AMPK signaling pathway. Hence, PZ-DHA is a promising therapeutic agent for insulin resistance in type 2 diabetes.

Glucosamine alleviates zearalenone-induced damage to porcine trophectoderm cells by activating the PI3K/AKT signaling pathway.

As one of the mycotoxins commonly found in feed and food, zearalenone (ZEA) mainly harms the reproductive functions of humans and animals. In our study, we investigated the protective effects of glucosamine (GlcN) on ZEA-induced apoptosis and oxidative damage of porcine trophectoderm (pTr) cells. Our results showed that 0.5 mmol L-1 GlcN significantly alleviated ZEA-induced decline in pTr cell viability. In addition, GlcN also significantly reversed other toxicity of ZEA to pTr cells, including G2/M phase arrest, DNA damage, reactive oxygen species (ROS) production, and barrier function disruption. Further studies indicated that GlcN can reduce apoptosis and autophagy in pTr cells in response to ZEA treatment. These results were confirmed by flow cytometry, transmission electron microscopy (TEM) and western blotting to detect the expressions of apoptosis and autophagy related proteins. Notably, GlcN activated the expressions of the PI3K/AKT signaling pathway related proteins, suggesting that its protective effect on pTr cells may be mediated by the PI3K/AKT signaling pathway. To demonstrate this mechanism, we used the PI3K/AKT pathway inhibitor wortmannin to pretreat pTr cells, and showed that the protective effect of GlcN on ZEA-induced pTr cytotoxicity was eliminated. In conclusion, GlcN was able to alleviate ZEA-induced toxic effects in pTr cells. This study also provides a theoretical basis for GlcN alleviating the adverse effects of ZEA on early embryo development and proved its potential application prospects.

Resveratrol alleviates enterotoxigenic Escherichia coli K88-induced damage by regulating SIRT-1 signaling in intestinal porcine epithelial cells.

This study found that resveratrol pretreatment attenuated porcine intestinal epithelial cell damage caused by enterotoxigenic Escherichia coli (ETEC) K88 in vitro and the protective effects of resveratrol were associated with SIRT-1 signaling. ETEC K88 is a main intestinal pathogen for post-weaning diarrhea (PWD) in piglets. With the strict ban on antibiotics in animal feed, people are seeking effective antibiotic substitutes to protect the intestinal system against harmful pathogenic bacteria. This study was conducted to evaluate the effects of resveratrol, a natural plant polyphenol, on ETEC K88-induced cellular damage in porcine enterocytes and underlying mechanisms. Intestinal porcine epithelial cell line 1 (IPEC-1) cells, pretreated with or without resveratrol (30 µM, 4 h), were challenged with ETEC K88 (MOI = 1 : 10) for 3 h. The results showed that ETEC K88 infection induced severe damage and dysfunction in IPEC-1 cells, as evidenced by a reduced cell viability, decreased tight junctions, mitochondrial dysfunction, and autophagy. It is noteworthy that IPEC-1 cells pre-treated with resveratrol improved their capacity for resistance to most of these abnormal phenotypes caused by ETEC K88 infection. Furthermore, we found that the activation of SIRT-1 signaling was associated with the benefits of resveratrol, as demonstrated by EX-527, an inhibitor of SIRT-1, which reversed most of the protective effects of resveratrol. In conclusion, these results indicated that resveratrol could protect intestinal epithelial cells against ETEC K88 infection by activating SIRT-1 signaling. These findings provide new insights into the role of resveratrol in maintaining intestinal physiological functions.

Kaempferol attenuates diquat-induced oxidative damage and apoptosis in intestinal porcine epithelial cells.

Kaempferol, a flavonol component of plants, is well-known to exhibit multiple bioactivities, such as anti-oxidative and anti-apoptotic effects. However, the underlying mechanisms responsible for the beneficial effects remain elusive. This study was conducted to test the hypothesis that kaempferol attenuated diquat-induced oxidative damage and intestinal barrier dysfunction by ameliorating oxidative damage and apoptosis in intestinal porcine epithelial cells. Compared with the control group, diquat treatment led to enhanced intracellular ROS production, increased mitochondrial depolarization, and apoptosis, which were accompanied by cell cycle arrest at the G1 phase, reduced cell migration, and disrupted intestinal epithelial barrier function. These effects triggered by diquat were reversed by kaempferol. Further study showed that the protective effect of kaempferol was associated with an enhanced mRNA level of genes related to cell cycle progression (cyclin D1, CDK4, and E2F1) and genes implicated in the anti-oxidant system (GSR, GSTA4, and HO-1), up-regulated abundance of tight junctions (ZO-1, ZO-2, occludin, and claudin-4), as well as enhanced Nrf2, an anti-oxidant transcription factor. In conclusion, we revealed a functional role of kaempferol in the intestinal barrier. Ingestion of kaempferol-rich foods might be a potential strategy to improve the integrity and function of enterocytes.

Quercetin Alleviates Oxidative Damage by Activating Nuclear Factor Erythroid 2-Related Factor 2 Signaling in Porcine Enterocytes.

Oxidative stress has been implicated in the etiology of multiple gastrointestinal disorders, such as irritable bowel syndrome and inflammatory bowel disease. This study was conducted to evaluate effects of natural product quercetin on diquat-induced oxidative stress in porcine enterocytes and underlying mechanisms. Intestinal porcine epithelial cell line 1 (IPEC-1) cells pretreated with or without quercetin (5 µM, 24 h) were incubated with vehicle or diquat (100 µM) for 6 h. The results showed that diquat treatment induced apoptosis in a caspase-3-dependent manner, as accompanied by elevated reactive oxygen species (ROS) production, increased mitochondrial depolarization, and reduced the abundance of tight junction proteins. These adverse effects of diquat were remarkably abrogated by quercetin administration. Further study indicated that the protective effect of quercetin was associated with elevated protein abundance of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased intracellular glutathione (GSH) content. Interestingly, the beneficial effects of quercetin on diquat-induced oxidative damage were abolished by all-trans-retinoic acid (Atra), a specific inhibitor of Nrf2, indicating a Nrf2-dependent regulation manner. The results show that quercetin attenuates diquat-induced cell injury by promoting protein abundance of Nrf2 and regulating GSH-related redox homeostasis in enterocytes. These findings provide new insights into a function role of quercetin in maintaining intestinal homeostasis.

Impact of Dietary Crude Protein Level on Hepatic Lipid Metabolism in Weaned Female Piglets.

Amino acids serve not only as building blocks for proteins, but also as substrates for the synthesis of low-molecular-weight substances involved in hepatic lipid metabolism. In the present study, eighteen weaned female piglets at 35 days of age were fed a corn- and soybean meal-based diet containing 20%, 17%, or 14% crude protein (CP), respectively. We found that 17% or 20% CP administration reduced the triglyceride and cholesterol concentrations, while enhanced high-density lipoprotein cholesterol (HDL-C) concentration in serum. Western blot analysis showed that piglets in the 20% CP group had higher protein abundance of hormone-sensitive triglyceride lipase (HSL) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), as compared with other groups. Moreover, the mRNA expression of sterol regulatory element binding transcription factor 1 (SREBPF1), fatty acid synthase (FASN), and stearoyl-CoA desaturase (SCD) were lower in the 17% or 20% CP group, compared with those of the piglets administered with 14% CP. Of note, the mRNA level of acetyl-CoA carboxylase alpha (ACACα) was lower in the 17% CP group, compared with other groups. Additionally, the mRNA level of lipoprotein lipase (LPL), peroxisome proliferator-activated receptor alpha α (PPARα), glucose-6-phosphatase catalytic subunit (G6PC), and phosphoenolpyruvate carboxykinase 1 (PKC1) in the liver of piglets in the 20% CP group were higher than those of the 14% CP group. Collectively, our results demonstrated that dietary CP could regulate hepatic lipid metabolism through altering hepatic lipid lipogenesis, lipolysis, oxidation, and gluconeogenesis.