Macleaya cordata extract alleviated oxidative stress and altered innate immune response in mice challenged with enterotoxigenic Escherichia coli

This study examines the effects of dietary Macleaya cordata extract (MCE) on bacterial burden and resistance to enterotoxigenic Escherichia coli (ETEC) in ICR mice. ICR mice were randomly distributed into one of the following groups: (i) basal diet; (ii) basal diet with 200 mg kg^-1 MCE; (iii) basal diet challenged with ETEC; and (iv) basal diet with 200 mg kg^-1 MCE and challenged with ETEC. Following a 7-day period of pre-treatment, CTRL-ETEC and MCE-ETEC mice were subjected to oral infection using 5×10⁸E. coli SEC 470. The results showed dietary 200 mg kg^-1 MCE markedly reduced intestinal ETEC burden (P < 0.05) and the disease-associated mortality was significantly alleviated in the MCE treated group (P < 0.05). In addition, dietary MCE markedly alleviated ETEC-induced oxidative stress, evidenced by the lowered methane dicarboxylic aldehyde (MDA) abundance and enhanced activities of catalase and glutathione peroxidase (P < 0.05). Furthermore, MCE mice exhibited higher immune activity, which might have further mediated ETEC infection. These results indicate MCE plays a preventative role with respect to ETEC infection. Future research should aim to develop MCE as a therapeutic approach to the promotion of intestinal health and a safeguard against ETEC infection.

L-Arginine Inhibited Inflammatory Response and Oxidative Stress Induced by Lipopolysaccharide via Arginase-1 Signaling in IPEC-J2 Cells

This study aimed to explore the effect of L-arginine on lipopolysaccharide (LPS)-induced inflammatory response and oxidative stress in IPEC-2 cells. We found that the expression of toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), cluster of differentiation 14 (CD14), nuclear factor-kappaBp65 (NF-κBp65), chemokine-8 (IL-8), tumor necrosis factor (TNF-α) and chemokine-6 (IL-6) mRNA were significantly increased by LPS. Exposure to LPS induced oxidative stress as reactive oxygen species (ROS) and malonaldehyde (MDA) production were increased while glutathione peroxidase (GSH-Px) were decreased in LPS-treated cells compared to those in the control. LPS administration also effectively induced cell growth inhibition through induction of G0/G1 cell cycle arrest. However, compared with the LPS group, cells co-treatment with L-arginine effectively increased cell viability and promoted the cell cycle into the S phase; L-arginine exhibited an anti-inflammatory effect in alleviating inflammation induced by LPS by reducing the abundance of TLR4, MyD88, CD14, NF-κBp65, and IL-8 transcripts. Cells treated with LPS+L-arginine significantly enhanced the content of GSH-Px, while they decreased the production of ROS and MDA compared with the LPS group. Furthermore, L-arginine increased the activity of arginase-1 (Arg-1), while Arg-1 inhibitor abolished the protection of arginine against LPS-induced inflammation and oxidative stress. Taken together, these results suggested that L-arginine exerted its anti-inflammatory and antioxidant effects to protect IPEC-J2 cells from inflammatory response and oxidative stress challenged by LPS at least partly via the Arg-1 signaling pathway.

l-Arginine Protects Ovine Intestinal Epithelial Cells from Lipopolysaccharide-Induced Apoptosis through Alleviating Oxidative Stress

This research aims to explore the effect of l-arginine (Arg) upon lipopolysaccharide (LPS)-induced induction of the oxidative stress as well as subsequent apoptosis within ovine intestinal epithelial cells (IOECs). Through a 16 h incubation, cells were divided into four groups and the medium was replaced with different medium as follows: (1) control (Con), Arg-free Dulbecco's modified Eagle's F12 Ham medium (DMEM); (2) Arg treatment, Arg-free DMEM supplemented with 100 μM Arg; (3) LPS treatment, Arg-free DMEM supplemented with 10 μg/mL LPS; (4) LPS with Arg treatment, Arg-free DMEM supplemented with both 10 μg/mL LPS and 100 μM Arg. After culturing for 24 h in different mediums, some characteristics of cells in the four groups were measured. Addition of Arg increased cell viability induced with LPS compared with the LPS group ( p < 0.05). Arg significantly decreased the release of dehydrogenase (LDH) and the production of malonaldehyde (MDA) ( p < 0.05) within IOECs challenged by the LPS. Compared with the LPS group, cells treated with Arg and Arg + LPS increased ( p < 0.05) mRNA as well as protein expression of glutathione peroxidase 1 (GPx1), catalase (CAT), superoxide dismutase 2 (SOD2), B-cell lymphoma 2 (Bcl2), quinone oxidoreductase 1 (NQO1), heme oxygenase (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). IOEC treatment with Arg reduced significantly ( p < 0.05) apoptosis induced by the LPS (12.58 ± 0.79%). The results showed that Arg promoted the protein expression of Nrf2, up-regulated expression of the phase II metabolizing enzymes (NQO1 and HO-1), as well as antioxidative enzymes (GPx1, CAT, and SOD2) for alleviating oxidative injury and protected IOECs from LPS-induced apoptosis.

Autophagy-Inducing Factor Atg1 Is Required for Virulence in the Pathogenic Fungus Candida glabrata

Candida glabrata is one of the leading causes of candidiasis and serious invasive infections in hosts with weakened immune systems. C. glabrata is a haploid budding yeast that resides in healthy hosts. Little is known about the mechanisms of C. glabrata virulence. Autophagy is a ‘self-eating’ process developed in eukaryotes to recycle molecules for adaptation to various environments. Autophagy is speculated to play a role in pathogen virulence by supplying sources of essential proteins for survival in severe host environments. Here, we investigated the effects of defective autophagy on C. glabrata virulence. Autophagy was induced by nitrogen starvation and hydrogen peroxide (H₂O₂) in C. glabrata. A mutant strain lacking CgAtg1, an autophagy-inducing factor, was generated and confirmed to be deficient for autophagy. The Cgatg1Δ strain was sensitive to nitrogen starvation and H₂O₂, died rapidly in water without any nutrients, and showed high intracellular ROS levels compared with the wild-type strain and the CgATG1-reconstituted strain in vitro. Upon infecting mouse peritoneal macrophages, the Cgatg1Δ strain showed higher mortality from phagocytosis by macrophages. Finally, in vivo experiments were performed using two mouse models of disseminated candidiasis and intra-abdominal candidiasis. The Cgatg1Δ strain showed significantly decreased CFUs in the organs of the two mouse models. These results suggest that autophagy contributes to C. glabrata virulence by conferring resistance to unstable nutrient environments and immune defense of hosts, and that Atg1 is a novel fitness factor in Candida species.

Splenectomy Promotes Macrophage Polarization in a Mouse Model of Concanavalin A- (ConA-) Induced Liver Fibrosis

Background

Splenectomy can improve liver function and survival in patients with autoimmune hepatitis (AIH) and liver cirrhosis. We investigated the underlying mechanism in a mouse model of concanavalin A- (ConA-) induced liver fibrosis.

Methods

We used ConA to induce immune liver fibrosis in BALB/c mice. Splenectomy was performed alone or with the administration of dexamethasone (DEX). Changes in blood and liver tissues were evaluated.

Results

Mice treated with ConA for 7 weeks developed advanced liver fibrosis, while splenectomy suppressed liver fibrosis. Although the populations of macrophages/monocytes and M1 macrophages decreased after splenectomy, the inflammatory factors associated with M2 macrophages increased after splenectomy. Furthermore, the population of circulating CD11b⁺Ly6C^high myeloid-derived suppressor cells (MDSCs) increased after splenectomy. After ConA treatment, elevated levels of activated and total NF-kBp65/p50 combined with DNA were observed in hepatic tissues. In contrast, the levels of NF-κB p65/p50 decreased after splenectomy.

Conclusions

Splenectomy may promote the polarization of CD11b⁺Ly6C^high MDSCs and the differentiation of M2 macrophages while restricting the level of NF-κB p65-p50 heterodimers. These factors may suppress the progression of liver fibrosis.

Tannic acid modulates intestinal barrier functions associated with intestinal morphology, antioxidative activity, and intestinal tight junction in a diquat-induced mouse model

The concentration of 2.5 mg kg⁻¹ TA can ameliorate diquat-challenged jejunal injury in mice.

Antioxidative, inflammatory and immune responses in hydrogen peroxide-induced liver injury of tilapia (GIFT, Oreochromis niloticus)

Oxidative stress has been implicated in the pathogenesis of many liver diseases in fish, but the molecular mechanism is still obscure. Here, we used hydrogen peroxide (H₂O₂) as a reactive oxygen species (ROS) to induce liver injury and assess underlying molecular mechanism linking oxidative stress and liver injury in fish. Tilapia were injected with various concentrations of H₂O₂ (0, 40, 120, 200, 300 and 400 mM) for 72 h. The blood and liver were collected to assay biochemical parameters and genes expression after 24, 48 and 72 h of injection. The results showed that treatments with higher H₂O₂ levels (300 and/or 400 mM) significantly increased the levels of GPT, GOT, AKP and MDA, and apparently decreased the levels of TP, ALB, SOD, GSH, CAT, GST and T-AOC throughout of the 72 h. The gene expression data showed that treatments with 200, 300 and/or 400 H₂O₂ suppressed Nrf2/keap1 pathway and its downstream genes including ho-1, nqo1 and gsta, activated inflammatory response via enhancing the mRNA levels of nf-κb, tnf-α, il-1β and il-8, and attenuating il-10 mRNA level, and caused immunotoxicity through downregulating the genes expression of c3, hep, lzm and Igm for 24, 48 and/or 72 h. Additionally, there was a mild or strong increase in levels of nrf2 and its subsequent antioxidant genes or enzymes such as ho-1, nqo1, gst, CAT and SOD in treatments with lower concentrations of H₂O₂ (40 or 120 mM) for 24 and/or 48 h. Overall results suggested that H₂O₂ hepatotoxicity was mainly concerned with lipid peroxidation, impairment antioxidant defense systems, inflammatory response and immunotoxicity, and Nrf2/Keap1 and NF-κB signaling pathways played important roles in oxidative stress-induced liver injury in fish.

Metabolic Regulation of Methionine Restriction in Diabetes

Although the effects of dietary methionine restriction have been investigated in the physiology of aging and diseases related to oxidative stress, the relationship between methionine restriction (MR) and the development of metabolic disorders has not been explored extensively. This review summarizes studies of the possible involvement of dietary methionine restriction in improving insulin resistance, glucose homeostasis, oxidative stress, lipid metabolism, the pentose phosphate pathway (PPP), and inflammation, with an emphasis on the fibroblast growth factor 21 and protein phosphatase 2A signals and autophagy in diabetes. Diets deficient in methionine may be a useful nutritional strategy in patients with diabetes.

Metabolic and Proteomic Responses to Long-Term Protein Restriction in a Pig Model

Protein restriction is associated with extended lifespan and reduced incidence and progression of multiple age-related diseases. The underlying mechanism of metabolic and proteomic responses to the long-term dietary protein restriction, however, has not been fully uncovered. The present study aimed to identify the metabolic and proteomic profiles in a low-protein diet-fed pig model. Intestinal and liver metabolomics showed that amino acid metabolism was highly associated with dietary protein restriction. Interestingly, blood was characterized by markedly higher abundances of Ser, Gly, Glu, Thr, Ala, Lys, and Met levels, and lower abundances of His, Val, and Ile levels regardless of the age of pigs from piglets to adult pigs. Amino acid transporters might contribute to the changed amino acid pools and serve as a feedback regulatory mechanism in response to protein restriction. iTRAQ-based quantitative proteomics approach identified more than 10 differently expressed proteins in protein restricted pigs and KEGG pathway analysis showed that significant enrichment of proteins involved in metabolic pathways, PI3K-Akt signaling pathway, lysosome, spliceosome, oxidative phosphorylation, phagosome, and DNA replication. Western blot analysis further confirmed that protein restriction markedly inactivated Akt and mTOR signals in pigs. This study indicates that dietary protein restriction leads to a shift in the host metabolism in a pig model, especially for amino acid metabolism. Along with proteomics, our findings unveil potential mechanisms for integrating how protein restriction modulates host metabolism.

Apigetrin treatment attenuates LPS-induced acute otitis media though suppressing inflammation and oxidative stress

The natural course of otitis media in children is acute and self-limiting. Nevertheless, about 10-20% children could experience recurrent or persistent otitis media. Thus, finding effective candidate to prevent acute otitis media is urgently required. In our study, mouse acute otitis media model was constructed by lipopolysaccharide (LPS) injection into the middle ear of mice via the tympanic membrane. Apigetrin (APT) is a flavonoid isolated from various herbal medicines, possessing anti-inflammatory and anti-oxidative bioactivities. However, if APT could attenuate acute otitis media in LPS-induced animal models, little is to be known. Hematoxylin and eosin (H&E) staining suggested that APT treatment reduced LPS-induced higher mucosa thickness. LPS-triggered inflammatory response was also inhibited by APT, as evidenced by the down-regulated neutrophils and macrophages. Additionally, the reduced inflammatory factors, including interleukin-1β (IL-lβ), tumor necrosis factor α (TNF-α), IL-6 and vascular endothelial growth factor (VEGF) were observed in APT-treated mice with acute otitis media. The process was associated with the inhibition of toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) pathway, which was proved by the blockage of TLR4, MyD88, p-IKKα, p-IκBα, and p-NF-κB using western blot analysis. Moreover, the production of reactive oxygen species (ROS) caused by LPS was also reduced by APT through promoting anti-oxidants, involving superoxide dismutase (SOD) activity, heme oxygenase-1 (HO-1), NADP(H) quinone oxidoreductase 1 (NQO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) expressions. In contrast, high levels of MDA and kelch-like ECH-associated protein 1 (Keap 1) in LPS-treated mice were down-regulated by APT, which might be associated with the inactivation of NF-κB. In vitro, APT exhibited anti-inflammatory and anti-oxidant effects with little cytotoxicity in LPS-stimulated cells. Together, the data above indicated that APT could ameliorate acute otitis media through inhibiting inflammation and oxidative stress.

Diquat-induced oxidative stress increases intestinal permeability, impairs mitochondrial function, and triggers mitophagy in piglets

In the present study, we investigated the influence of diquat-induced oxidative stress on intestinal barrier, mitochondrial function, and the level of mitophagy in piglets. Twelve male Duroc × Landrace × Yorkshire 35-d-old pigs (weaned at 21 d of age), with an average body of 9.6 kg, were allotted to two treatments of six piglets each including the challenged group and the control group. The challenged pigs were injected with 100 mg/kg bodyweight diquat and control pigs injected with 0.9% (w/v) NaCl solution. The results showed that diquat injection decreased ADFI and ADG. Diquat decreased (P < 0.05) the activities of superoxide dismutase and glutathione peroxidase and increased (P < 0.05) the malondialdehyde concentrations. The lower (P < 0.05) transepithelial electrical resistance and higher (P < 0.05) paracellular permeability of fluorescein isothiocyanatedextran 4 kDa were found in diquat challenged piglets. Meanwhile, diquat decreased (P < 0.05) the protein abundance of claudin-1, occluding, and zonula occludens-1 in jejunum compared with the control group. Diquat-induced mitochondrial dysfunction, as demonstrated by increased (P < 0.05) reactive oxygen species production and decreased (P < 0.05) membrane potential of intestinal mitochondria. Diquat-injected pigs revealed a decrease (P < 0.05) of mRNA abundance of genes related to mitochondrial biogenesis and functions, PPARg coactivator-1α, mammalian-silencing information regulator-1, nuclear respiratory factor-1, mt transcription factor A, mt single-strand DNA-binding protein, mt polymerase r, glucokinase, citrate synthase, ATP synthase, and cytochrome coxidase subunit I and V in the jejunum. Diquat induced an increase (P < 0.05) in expression of mitophagy-related proteins, phosphatase and tensin homologue deleted on chromosome 10-induced putative kinase, and Parkin in the intestinal mitochondria, as well as an enhancement of the ratio of light chain 3-II (LC3-II) to LC3-I content in the jejunal mucosa. These results suggest that oxidative stress disrupted the intestinal barrier, caused mitochondrial dysfunction, and triggered mitophagy.

Dietary chlorogenic acid improves growth performance of weaned pigs through maintaining antioxidant capacity and intestinal digestion and absorption function

Chlorogenic acid (CGA) is a natural phenolic acid, which is an important component of biologically active dietary phenols isolated from various species. Two experiments were conducted to investigate the effects of CGA on growth performance, antioxidant capacity, nutrient digestibility, diarrhea incidence, intestinal digestion and absorption function, and the expression levels of intestinal digestion and absorption-related genes in weaned pigs. In Exp. 1, 200 weaned pigs were randomly allotted to four dietary treatments and fed with a basal diet or a basal diet supplemented with 250, 500, or 1,000 mg/kg CGA, respectively, in a 14-d trial. Pigs on the 1,000 mg/kg CGA-supplemented group had greater (P < 0.05) G:F compared with those on the control (CON) group. In Exp. 2, 24 weaned pigs were randomly allotted to two groups and fed with a basal diet (CON group) or a basal diet supplemented with 1,000 mg/kg CGA (the optimum does from Exp. 1; CGA group). After a 14-d trial, 8 pigs per treatment were randomly selected to collect serum and intestinal samples. Compared with the CON group, the ADG, G:F, as well as the apparent total tract digestibility of CP, crude fat, and ash were increased (P < 0.05), whereas the diarrhea incidence was decreased (P < 0.05) in the CGA group. Pigs on the CGA group had greater (P < 0.05) serum albumin and IGF-1, and lower (P < 0.05) serum urea nitrogen than pigs on the CON group. Furthermore, dietary CGA supplementation enhanced (P < 0.05) the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in the serum, the activity of maltase in the jejunum and ileum, as well as the activities of sucrase and alkaline phosphatase (AKP) in the jejunum. The mRNA levels of sodium glucose transport protein-1 (SGLT1) and zinc transporter-1 (ZNT1) in the duodenum and the mRNA levels of SGLT1, glucose transporter-2 (GLUT2), and divalent metal transporter-1 (DMT1) in the jejunum were upregulated (P < 0.05) in pigs fed the CGA diet. These results suggested that dietary CGA supplementation has the potentials to improve the growth performance and decrease the diarrhea incidence of the weaned pigs, possibly through improving the antioxidant capacity and enhancing the intestinal digestion and absorption function.

Weaning disrupts intestinal antioxidant status, impairs intestinal barrier and mitochondrial function, and triggers mitophagy in piglets

In the present study, we investigated the influence of weaning on antioxidant status, intestinal integrity, mitochondrial function, and the mitophagy level in piglets (weaned at 21 d) during the 1 wk after weaning. The redox status was measured by antioxidant enzymes activities, related genes expression, and malondialdehyde (MDA) content in jejunum. The intestinal barrier function was assessed by the Ussing chamber and expression of tight junction proteins in the jejunum. The function of intestine mitochondria was measured by mitochondrial DNA (mtDNA) content and activities of mitochondria oxidative phosphorylation complexes. The levels of light chain 3-1 (LC3-I), light chain 3-II (LC3-II), PTEN-induced putative kinase 1 (PINK1), and Parkin were determined to investigate whether mitophagy is involved in the weaning process. The results showed that, as compared with the preweaning phase (d 0), weaning suppressed (P < 0.05) the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) on d 3 and d 7 postweaning, decreased (P < 0.05) the expression of copper and zinc superoxide dismutase (Cu/Zn-SOD), manganese-containing superoxide dismutase (Mn-SOD) on d 3 postweaning, declined (P < 0.05) the level of glutathione peroxidase 1 (GPX-1) and glutathione peroxidase 4 (GPX-4) on d 3 and d 7 postweaning, and increased (P < 0.05) MDA content in jejunum on d 3 and d 7 postweaning. The jejunal transepithelial electrical resistance and levels of occludin, claudin-1, and zonula occludens-1 on d 3 and d 7 postweaning were reduced (P < 0.05), and paracellular flux of fluorescein isothiocyanatedextran (4 kDa) on d 3 and d 7 postweaning was increased (P < 0.05). Weaning induced mitochondrial dysfunction, as demonstrated by decreased (P < 0.05) content of mtDNA on d 3 and d 7 postweaning and declined (P < 0.05) activities of mitochondria complexes (I, II, III, IV) in jejunum on d 1, d 3, and d 7 postweaning. Weaning led to an increased (P < 0.05) expression level of mitophagy-related proteins, PINK1 and Parkin, in the intestinal mitochondria, as well as an enhancement (P < 0.05) of the ratio of LC3-II to LC3-I content in the jejunal mucosa on d 1, d 3, and d 7 postweaning. These results suggest that weaning disrupted intestinal oxidative balance, and this imbalance may impair intestinal barrier and mitochondrial function and trigger mitophagy in piglets.

Induction of nuclear factor-κB signal-mediated apoptosis and autophagy by reactive oxygen species is associated with hydrogen peroxide-impaired growth performance of broilers

The oxidative study has always been particularly topical in poultry science. However, little information about the occurrence of cellular apoptosis and autophagy through the reactive oxygen species (ROS) generation in nuclear factor-κB (NF-κB) signal pathway was reported in the liver of broilers exposed to hydrogen peroxide (H2O2). So we investigated the change of growth performance of broilers exposed to H2O2 and further explored the occurrence of apoptosis and autophagy, as well as the expression of NF-κB in these signaling pathways in the liver. A total of 320 1-day-old Arbor Acres male broiler chickens were raised on a basal diet and randomly divided into five treatments which were arranged as non-injected treatment (Control), physiological saline (0.75%) injected treatment (Saline) and H2O2 treatments (H2O2(0.74), H2O2(1.48) and H2O2(2.96)) received an intraperitoneal injection of H2O2 with 0.74, 1.48 and 2.96 mM/kg BW. The results showed that compared to those in the control and saline treatments, 2.96 mM/kg BW H2O2-treated broilers exhibited significantly higher feed/gain ratio at 22 to 42 days and 1 to 42 days, ROS formation, the contents of oxidation products, the mRNA expressions of caspases (3, 6, 8), microtubule-associated protein 1 light chain 3 (LC3)-II/LC3-I, autophagy-related gene 6, Bcl-2 associated X and protein expressions of total caspase-3 and total LC3-II, and significantly lower BW gain at 22 to 42 days and 1 to 42 days, the activities of total superoxide dismutase and glutathione peroxidase, the expression of NF-κB in the liver. Meanwhile, significantly higher feed/gain ratio at 1 to 42 days, ROS formation, the contents of protein carbonyl and malondialdehyde, the mRNA expression of caspase-3 and the protein expressions of total caspase-3 and total LC3-II, as well as significantly lower BW gain at 22 to 42 days and 1 to 42 days were observed in broilers received 1.48 mM/kg BW H2O2 treatment than those in control and saline treatments. These results indicated that oxidative stress induced by H2O2 had a negative effect on histomorphology and redox status in the liver of broilers, which was associated with a decline in growth performance of broilers. This may attribute to apoptosis and autophagy processes triggered by excessive ROS that suppress the NF-κB signaling pathway.

LPS challenge increased intestinal permeability, disrupted mitochondrial function and triggered mitophagy of piglets

Here we investigated the influence of LPS-induced gut injury on antioxidant homeostasis, mitochondrial (mt) function and the level of mitophagy in piglets. The results showed that LPS-induced intestinal injury decreased the transepithelial electrical resistance, increased the paracellular permeability of F1TC dextran 4 kDa, and decreased the expression of claudin-1, occludin and zonula occludens-1 in the jejunum compared with the control group. LPS decreased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and increased the content of malondialdehyde in the jejunum. Meanwhile, the expression of SOD-related genes ( Cu/Zn-SOD, Mn-SOD) and GSH-Px-related genes ( GPX-1, GPX-4) declined in LPS-challenged pigs compared with the control. LPS also increased TNF-α, IL-6, IL-8 and IL-1β mRNA expression. LPS induced mt dysfunction, as demonstrated by increased reactive oxygen species production and decreased membrane potential of intestinal mitochondria, intestinal content of mt DNA and activities of the intestinal mt respiratory chain. Furthermore, LPS induced an increase in expression of mitophagy related proteins, PTEN-induced putative kinase (PINK1) and Parkin in the intestinal mitochondria, as well as an enhancement of the ratio of light chain 3-II (LC3-II) to LC3-I content in the jejunal mucosa. These results suggested that LPS-induced intestinal injury accompanied by disrupted antioxidant homeostasis, caused mt dysfunction and triggered mitophagy.

Effects of Dietary l-Arginine and N-Carbamylglutamate Supplementation on Intestinal Integrity, Immune Function, and Oxidative Status in Intrauterine-Growth-Retarded Suckling Lambs

This study investigated the effects of dietary l-arginine (Arg) and N-carbamylglutamate (NCG) supplementation on intestinal integrity, immune function, and oxidative status in intrauterine-growth-retarded (IUGR) suckling lambs. A total of 48 newborn Hu lambs of normal birth weight (CON) and IUGR were allocated randomly into four groups of 12 animals each: CON, IUGR, IUGR + 1% Arg, or IUGR + 0.1% NCG. All lambs were raised for a period of 21 days from 7 to 28 days after birth. The Arg or NCG group exhibited improved ( p < 0.05) final body weights compared to that of the IUGR group. In comparison to the IUGR lambs, the apoptotic percentage was lower ( p < 0.05) in the ileum of IUGR lambs supplemented with Arg and NCG. In addition, in comparison to IUGR, the concentrations of protein carbonyl and malondialdehyde were lower ( p < 0.05) and the reduced glutathione (GSH) concentration and ratio of GSH/oxidized glutathione were greater ( p < 0.05) in the jejunum, duodenum, and ileum of IUGR + 1% Arg or 0.1% NCG lambs. In comparison to the IUGR group, the mRNA abundance of myeloid differentiation factor 88, toll-like receptor 9, toll-like receptor 4, interleukin 6, and fuclear factor-κB was lower ( p < 0.05) and the mRNA abundance of superoxide dismutase 1, B-cell lymphoma/leukaemia 2, zonula occludens-1 (ZO-1), and occludin was greater in the ileum of the IUGR lambs supplemented with Arg or NCG. Furthermore, the protein abundance of ZO-1 and claudin-1 in the ileum was greater ( p < 0.05) in the IUGR + 1% Arg or 0.1% NCG lambs. The results show that Arg or NCG supplementation improves the growth, intestinal integrity, immune function, and oxidative status in IUGR Hu suckling lambs.

Epidermal Growth Factor, through Alleviating Oxidative Stress, Protect IPEC-J2 Cells from Lipopolysaccharides-Induced Apoptosis

The epidermal growth factor (EGF) has been widely used for protection of stress-induced intestinal mucosa dysfunction. However, whether EGF would alleviate oxidative injury and reduce apoptosis in porcine intestine is not yet known. Therefore, the aim of this study was to investigate the effect of EGF on lipopolysaccharides (LPS)-induced induction of oxidative stress and ensuing apoptosis in the porcine intestinal epithelial cell line, IPEC-J2. The present study showed that EGF significantly increased cell viability and decreased the LPS-induced induction of apoptosis, dehydrogenase (LDH) release and malonaldehyde (MDA) production. EGF also (i) decreased expression of the pro-apoptotic genes Fas, Bax, Cascase-3, Cascase-8, Cascase-9, and proteins such as P53, Fas, Bax, Caspase3; (ii) increased antiapoptotic protein B-cell lymphoma 2 (Bcl2) expression; (iii) increased mRNA levels of the nuclear factor erythroid 2-related factor 2 (Nrf2) related genes Nrf2, manganese superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GSH-Px), heme oxygenase (HO-1) and quinone oxidoreductase (NQO1); (iv) protein level of Nrf2-realeted proteins Nrf2, HO-1, NQO1; and (v) total antioxidant capacity (T-AOC), CAT, SOD, GSH-Px concentrations. Collectively, our results indicated that EGF enhanced Nrf2 protein expression, and upregulated the expression of phase II metabolizing enzymes (such as HO-1 and NQO1) and antioxidative enzymes (SOD, CAT and GSH-Px) to alleviate oxidative injury, and then protect IPEC-J2 cells from apoptosis induced by LPS.

Toxicity assessment of hydrogen peroxide on Toll-like receptor system, apoptosis, and mitochondrial respiration in piglets and IPEC-J2 cells

In this study, expressions of toll-like receptors (TLRs) and apoptosis-related genes in piglets and mitochondrial respiration in intestinal porcine epithelial cells were investigated after hydrogen peroxide (H₂O₂) exposure. The in vivo results showed that H₂O₂ influenced intestinal expressions of TLRs and apoptosis related genes. H₂O₂ treatment (5% and 10%) downregulated uncoupling protein 2 (UCP2) expression in the duodenum (P < 0.05), while low dosage of H2O2 significantly increased UCP2 expression in the jejunum (P < 0.05). In IPEC-J2 cells, H₂O₂ inhibited cell proliferation (P < 0.05) and caused mitochondrial dysfunction via reducing maximal respiration, spare respiratory, non-mitochondrial respiratory, and ATP production (P < 0.05). However, 50 uM H₂O₂ significantly enhanced mitochondrial proton leak (P < 0.05). In conclusion, H₂O₂ affected intestinal TLRs system, apoptosis related genes, and mitochondrial dysfunction in vivo and in vitro models. Meanwhile, low dosage of H₂O₂ might exhibit a feedback regulatory mechanism against oxidative injury via increasing UCP2 expression and mitochondrial proton leak.

Inhibition of Heat Shock proteins HSP90 and HSP70 induce oxidative stress, suppressing cotton fiber development

Cotton fiber is a specialized unicellular structure useful for the study of cellular differentiation and development. Heat shock proteins (HSPs) have been shown to be involved in various developmental processes. Microarray data analysis of five Gossypium hirsutum genotypes revealed high transcript levels of GhHSP90 and GhHSP70 genes at different stages of fiber development, indicating their importance in the process. Further, we identified 26 and 55 members of HSP90 and HSP70 gene families in G. hirsutum. The treatment of specific inhibitors novobiocin (Nov; HSP90) and pifithrin/2-phenylethynesulfonamide (Pif; HSP70) in in-vitro cultured ovules resulted in a fewer number of fiber initials and retardation in fiber elongation. The molecular chaperone assay using bacterially expressed recombinant GhHSP90-7 and GhHSP70-8 proteins further confirmed the specificity of inhibitors. HSP inhibition disturbs the H₂O₂ balance that leads to the generation of oxidative stress, which consequently results in autophagy in the epidermal layer of the cotton ovule. Transmission electron microscopy (TEM) of inhibitor-treated ovule also corroborates autophagosome formation along with disrupted mitochondrial cristae. The perturbations in transcript profile of HSP inhibited ovules show differential regulation of different stress and fiber development-related genes and pathways. Altogether, our results indicate that HSP90 and HSP70 families play a crucial role in cotton fiber differentiation and development by maintaining cellular homeostasis.

Effects of dietary lysine restriction on inflammatory responses in piglets

The aim of this study was to investigate the effects of lysine restriction on inflammatory responses in piglets. 38 male piglets with similar body weight of 9.62 kg were randomly divided into control group (basal diet) and lysine-restricted group (diet containing 70% lysine of the control diet). The results showed that lysine restriction increased the serum concentration of IgG an IgM. Piglets fed the lysine-restricted diet exhibited overexpression of interleukin-8 (IL-8) in the kidney (P < 0.05) and IL-6 and IL-4 in the spleen (P < 0.05). The mRNA abundances of IL-4 in the kidney (P < 0.05) and IL-10 in the liver (P < 0.05) were significantly lower in the lysine-restricted group compared with the control group. Meanwhile, lysine restriction increased the mRNA level of Tlr8 in the kidney (P < 0.05) but decreased the mRNA level of Tlr8 in the liver (P < 0.05). Finally, lysine restriction markedly enhanced extracellular signal regulated kinases 1/2 (ERK1/2) phosphorylation in the kidney and liver and nuclear transcription factor kappa B (NF-κB) was activated in the liver and spleen in response to dietary lysine restriction. In conclusion, lysine restriction affected inflammatory responses in the kidney, liver, and spleen via mediating serum antibody volume, inflammatory cytokines, Tlrs system, and ERK1/2 and NF-κB signals in piglets.

Long-term effects of lysine concentration on growth performance, intestinal microbiome, and metabolic profiles in a pig model

Lysine is a common limiting amino acid in human and animal diets and plays an important role in cell proliferation and metabolism.

Effects of Lysine deficiency and Lys-Lys dipeptide on cellular apoptosis and amino acids metabolism

SCOPE

Lysine (Lys) is a common limiting amino acids (AA) for humans and animals and plays an important role in cell proliferation and metabolism, while metabolism of Lys deficiency and its dipeptide is still obscure. Thus, this study mainly investigated the effects of Lys deficiency and Lys-Lys dipeptide on apoptosis and AA metabolism in vitro and in vivo models.

METHODS AND RESULTS

Lys deficiency induced cell-cycle arrest and apoptosis and upregulated Lys transporters in vitro and in vivo. SLC7A11, a cystine-glutamate antiporter, was markedly upregulated by Lys deficiency and then further mediated cystine uptake and glutamate release, which was negatively regulated by cystine and glutamate transporters. Meanwhile, Lys deprivation upregulated pept1 expression, which might improve Lys-Lys dipeptide absorption to compensate for the reduced Lys availability. Lys-Lys dipeptide alleviated Lys deficiency induced cell-cycle arrest and apoptosis and influenced AA metabolism. Furthermore, the mammalian target of rapamycin signal might be involved in sensing cellular Lys starvation and Lys-Lys dipeptide.

CONCLUSIONS

Altogether, these studies suggest that Lys deficiency impairs AA metabolism and causes apoptosis. Lys-Lys dipeptide serves as a Lys source and alleviates Lys deficiency induced cellular imbalance.

Arginine metabolism and its protective effects on intestinal health and functions in weaned piglets under oxidative stress induced by diquat

The intestine plays key roles in maintaining body arginine (Arg) homoeostasis. Meanwhile, the intestine is very susceptible to reactive oxygen species. In light of this, the study aimed to explore the effects of Arg supplementation on intestinal morphology, Arg transporters and metabolism, and the potential protective mechanism of Arg supplementation in piglets under oxidative stress. A total of thirty-six weaned piglets were randomly allocated to six groups with six replicates and fed a base diet (0·95 % Arg,) or base diet supplemented with 0·8 % and 1·6 % l-Arg for 1 week, respectively. Subsequently, a challenge test was conducted by intraperitoneal injection of diquat, an initiator of radical production, or sterile saline. The whole trial lasted 11 d. The diquat challenge significantly decreased plasma Arg concentration at 6 h after injection (P<0·05), lowered villus height in the jejunum and ileum (P<0·05) as well as villus width and crypt depth in the duodenum, jejunum and ileum (P<0·05). Oxidative stress significantly increased cationic amino acid transporter (CAT)-1, CAT-2 and CAT-3, mRNA levels (P<0·05), decreased arginase II (ARGII) and inducible nitric oxide synthase mRNA levels, and increased TNF- α mRNA level in the jejunum (P<0·05). Supplementation with Arg significantly decreased crypt depth (P<0·05), suppressed CAT-1 mRNA expression induced by diquat (P<0·05), increased ARGII and endothelial nitric oxide synthase mRNA levels (P<0·05), and effectively relieved the TNF- α mRNA expression induced by diquat in the jejunum (P<0·05). It is concluded that oxidative stress decreased Arg bioavailability and increased expression of inflammatory cytokines in the jejunum, and that Arg supplementation has beneficial effects in the jejunum through regulation of the metabolism of Arg and suppression of inflammatory cytokine expression in piglets.

Species-specific immunity to Helicobacter suis

BACKGROUND

Helicobacter (H.) suis is mainly associated with pigs, but is also the most prevalent gastric non-H. pylori Helicobacter species found in humans. Both H. pylori and H. suis may cause persistent infection of the stomach. Several immune evasion mechanisms have been proposed for H. pylori, which focus to a great extent on its major virulence factors, which are absent in H. suis. The aim of this study was to gain more knowledge on immune evasion by H. suis.

MATERIALS AND METHODS

Cytokine expression kinetics were monitored in the stomach of BALB/c mice experimentally infected with H. suis. The cytokine expression profile in the stomach of naturally H. suis-infected pigs was also determined. Subsequently, the effect of H. suis on murine and porcine dendritic cell (DC) maturation and their ability to elicit T-cell effector responses was analyzed.

RESULTS

Despite a Th17/Th2 response in the murine stomach, the inflammatory cell influx was unable to clear H. suis infection. H. suis-stimulated murine bone marrow-derived dendritic cells induced IL-17 secretion by CD4⁺ cells in vitro. Natural H. suis infection in pigs evoked increased expression levels of IL-17 mRNA in the antrum and IL-10 mRNA in the fundus. In contrast to mice, H. suis-stimulated porcine monocyte-derived dendritic cells were unable to express MHCII molecules on their cell surface. These semimature DCs induced proliferation of T-cells, which showed an increased expression of TGF-β and FoxP3 mRNA levels.

CONCLUSIONS

Helicobacter suis might evade host immune responses by skewing toward a Treg-biased response.

Short-term supplementation of isocaloric meals with L-tryptophan affects pig growth

L-Tryptophan (Trp) and some of its metabolites regulate the circadian rhythm in mammals. We aimed to investigate the effects of short-term supplementation of Trp in isocaloric meals on growth performance using the parameters of multiple blood biomarkers and free amino acids in growing pigs. A total of 32 Landrace × Yorkshire barrows with a mean body weight of 8.64 (±1.13) kg were randomly assigned to four groups and then fed with various concentrations of Trp diets daily. Our results showed that sequential supplementation of different concentrations of Trp in isocaloric meals decreased the feed:gain (F:G) ratio (P = 0.079) and plasma urea and albumin (P = 0.019), whereas the level of total protein did not. Among the essential and conditionally essential amino acids, the concentrations of histidine, isoleucine, proline, threonine, arginine, and valine in the plasma decreased (P < 0.05), whereas the concentrations of Trp, glycine, serine, and methionine increased (P < 0.01). In addition, concentrations of branched chain amino acids also significantly decreased (P = 0.004), while the rate of conversion of Trp to branched chain amino acids increased (P < 0.001). Taken together, we show that administration of a high concentration of Trp in breakfast with decreasing concentrations of Trp in lunch and dinner positively affected feed utilization and improved feed efficiency, at least in part, through the optimization of amino acid interconversions and nitrogen utilization.

Dietary soy isoflavones alleviate dextran sulfate sodium-induced inflammation and oxidative stress in mice

It has been hypothesized that soy isoflavones exhibit anti-oxidative and anti-inflammatory functions, however, the effects of soy isoflavones on inflammatory bowel diseases remain unknown. Therefore, the present study aimed to investigate the effect and underlying mechanism of dietary soy isoflavones on dextran sulfate sodium (DSS)-induced colitis. Mice were administered DSS and soy isoflavones, and histomorphometry, oxidative stress, inflammation and intestinal tight junctions were determined. The current study demonstrated that dietary soy isoflavones alleviated DSS-induced growth suppression, colonic inflammatory response, oxidative stress and colonic barrier dysfunction. DSS treatment was indicated to activate Toll-like receptor 4 (TRL4) and myeloid differentiation protein 88 (MyD88) in mice, whereas dietary soy isoflavones inhibited Myd88 expression in DSS-challenged mice. In conclusion, dietary soy isoflavones alleviate DSS-induced inflammation in mice, which may be associated with enhancing antioxidant function and inhibiting the TLR4/MyD88 signal.

Hydrogen Peroxide-Induced Change in Meat Quality of the Breast Muscle of Broilers Is Mediated by ROS Generation, Apoptosis, and Autophagy in the NF-κB Signal Pathway

We investigated the relationship between meat quality and oxidative damage caused by hydrogen peroxide (H₂O₂) in the breast muscle of broilers. Moreover, we explored the occurrence of apoptosis and autophagy, as well as the expression of NF-κB in these signaling pathways to provide evidence of possible oxidative damage mechanisms. The broilers received a basal diet and were randomly divided into five treatments (noninjected control, 0.75% saline-injected, and 2.5%, 5.0%, or 10.0% H₂O₂-injected treatments; 1.0 mL/kg in body weight). The results showed that oxidative stress induced by H₂O₂ had a negative effect on relative muscle weight, histomorphology, and redox status, while the underlying oxidative damage caused a decline in meat quality (decrease of pH_24h, 10% H₂O₂ treatment; increase of shear force, 5% and 10% H₂O₂ treatments) of broilers. This could be attributed to the apoptosis and autophagy processes triggered by excessive reactive oxygen species that suppress the NF-κB signaling pathway.

Dietary Zinc Oxide Modulates Antioxidant Capacity, Small Intestine Development, and Jejunal Gene Expression in Weaned Piglets

The current study was conducted to investigate the effects of dietary zinc oxide (ZnO) on the antioxidant capacity, small intestine development, and jejunal gene expression in weaned piglets. Ninety-six 21-day-old piglets were randomly assigned to three dietary treatments. Each treatment had eight replicates with four piglets per replicate. The piglets were fed either control diet (control) or control diet supplemented with in-feed antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) or pharmacological doses of ZnO (3000 mg/kg). The experiment lasted 4 weeks. Blood samples were collected at days 14 and 28, while intestinal samples were harvested at day 28 of the experiment. Dietary high doses of ZnO supplementation significantly increased the body weight (BW) at day 14 and average daily gain (ADG) of days 1 to 14 in weaned piglets, when compared to control group (P < 0.05). The incidence of diarrhea of piglets fed ZnO-supplemented diets, at either days 1 to 14, days 14 to 28, or the overall experimental period, was significantly decreased in comparison with those in other groups (P < 0.05). Supplementation with ZnO increased the villus height of the duodenum and ileum in weaned piglets and decreased the crypt depth of the duodenum, when compared to the other groups (P < 0.05). Dietary ZnO supplementation decreased the malondialdehyde (MDA) concentration at either day 14 or day 28, but increased total superoxide dismutase (T-SOD) at day 14, when compared to that in the control (P < 0.05). ZnO supplementation upregulated the messenger RNA (mRNA) expression of zonula occludens-1 (ZO-1) and occludin in the jejunum mucosa of weaned piglets, compared to those in the control (P < 0.05). The pro-inflammatory cytokine interleukin-lβ (IL-1β) mRNA expression in the jejunum mucosa was downregulated in the ZnO-supplemented group, compared with the control (P < 0.05). Both in-feed antibiotics and ZnO supplementation decreased the mRNA expression of interferon-γ (IFN-γ), but increased the mRNA expression of transforming growth factor-β (TGF-β), in the jejunum mucosa of piglets, when compared to those in the control (P < 0.05). In summary, supplemental ZnO was effective on the prevention of post-weaning diarrhea (PWD) in weaned piglets and showed comparative growth-promoting effect on in-feed antibiotics, probably by the mechanism of improvement of the antioxidant capacity, restoration of intestinal barrier function and development, and modulation of immune functions.

Hydrogen sulfide from a NaHS source attenuates dextran sulfate sodium (DSS)-induced inflammation via inhibiting nuclear factor-κB

This study investigated the alleviating effects of hydrogen sulfide (H2S), derived from sodium hydrosulfide (NaHS), on inflammation induced by dextran sulfate sodium (DSS) in both in vivo and in vitro models. We found that NaHS injection markedly decreased rectal bleeding, diarrhea, and histological injury in DSS-challenged mice. NaHS (20 μmol/L) reversed DSS-induced inhibition in cell viability in Caco-2 cells and alleviated pro-inflammation cytokine expression in vivo and in vitro, indicating an anti-inflammatory function for H2S. It was also found that H2S may regulate cytokine expression by inhibiting the nuclear factor-κB (NF-κB) signaling pathway. In conclusion, our results demonstrated that H2S alleviated DSS-induced inflammation in vivo and in vitro and that the signal mechanism might be associated with the NF-κB signaling pathway.

N-Acetyl-L-cysteine Protects the Enterocyte against Oxidative Damage by Modulation of Mitochondrial Function

The neonatal small intestine is susceptible to damage caused by oxidative stress. This study aimed to evaluate the protective role of antioxidant N-acetylcysteine (NAC) in intestinal epithelial cells against oxidative damage induced by H₂O₂. IPEC-J2 cells were cultured in DMEM-H with NAC and H₂O₂. After 2-day incubation, IPEC-J2 cells were collected for analysis of DNA synthesis, antioxidation capacity, mitochondrial respiration, and cell apoptosis. The results showed that H₂O₂ significantly decreased (P < 0.05) proliferation rate, mitochondrial respiration, and antioxidation capacity and increased cell apoptosis and the abundance of associated proteins, including cytochrome C, Bcl-XL, cleaved caspase-3, and total caspase-3. NAC supplementation remarkably increased (P < 0.05) proliferation rate, antioxidation capacity, and mitochondrial bioenergetics but decreased cell apoptosis. These findings indicate that NAC might rescue the intestinal injury induced by H₂O₂.

The use of Lactobacillus as an alternative of antibiotic growth promoters in pigs: A review

Antibiotics, often supplemented in feed, used as a growth promoter, may cause their residual effect in animal produce and also trigger antibiotic resistance in bacteria, which is of serious concern among swine farming entrepreneurs. As an alternative, supplementing probiotics gained interest in recent years. Lactobacillus being the most commonly used probiotic agent improves growth performance, feed conversion efficiency, nutrient utilization, intestinal microbiota, gut health and regulates immune system in pigs. The characteristics of Lactobacillus spp. and their probiotic effects in swine production are reviewed here under.

Analysis of Serum microRNA Expression Profiles and Comparison with Small Intestinal microRNA Expression Profiles in Weaned Piglets

Weaning stress induces tissue injuries and impairs health and growth in piglets, especially during the first week post-weaning. MicroRNAs (miRNAs) play vital roles in regulating stresses and diseases. Our previous study found multiple differentially expressed miRNAs in small intestine of piglets at four days post-weaning. To better understand the roles of miRNAs during weaning stress, we analyzed the serum miRNA expressional profile in weaned piglets (at four days post-weaning) and in suckling piglets (control) of the same age using miRNA microarray technology. We detected a total of 300 expressed miRNAs, 179 miRNAs of which were differentially expressed between the two groups. The miRNA microarray results were validated by RT-qPCR. The biological functions of these differentially expressed miRNAs were predicted by GO terms and KEGG pathway annotations. We identified 10 highly expressed miRNAs in weaned piglets including miR-31, miR-205, and miR-21 (upregulated) and miR-144, miR-30c-5p, miR-363, miR-194a, miR-186, miR-150, and miR-194b-5p (downregulated). Additionally, miR-194b-5p expression was significantly downregulated in serum and small intestine of weaned piglets. Our results suggest that weaning stress affects serum miRNA profiles in piglets. And serum miR-194b-5p levels can reflect its expressional changes in small intestine of piglets by weaning stress.

Long-term effects of oral tea polyphenols and Lactobacillus brevis M8 on biochemical parameters, digestive enzymes, and cytokines expression in broilers

This study investigates the long-term effects of oral tea polyphenols (TPs) and Lactobacillus brevis M8 (LB) on biochemical parameters, digestive enzymes, and cytokines expression in broilers. In experiment 1, 240 broiler chickens were selected to investigate the effects of 0.06 g/kg body weight (BW) TP and 1.0 ml/kg BW LB on broilers; in experiment 2, 180 broiler chickens were assigned randomly to three groups to investigate the effects of different dosages of TP (0.03, 0.06, and 0.09 g/kg BW) combined with 1.0 ml/kg BW LB on broilers; in experiment 3, 180 broiler chickens were assigned randomly to three groups to investigate the effects of different dosages of LB (0.5, 1.0, and 1.5 ml/kg BW) combined with 0.06 g/kg BW TP on broilers. The results showed that TP and LB affected serum biochemical parameters, and TP reduced serum cholesterol (CHO) and low-density lipoprotein cholesterol (LDL-C) abundances in a dosage-dependent manner (P<0.05) on Day 84. Meanwhile, broilers fed a diet supplemented with TP or LB had a lower intestinal lipase activity on Day 84 compared with the control group (P<0.05). Middle and high dosages of TP increased pancreatic lipase and proventriculus pepsin activities (P<0.05). Also middle and high dosages of LB significantly enhanced pancreatic lipase activity (P<0.05), while high LB supplementation inhibited intestinal trypsase (P<0.05) on Day 84. Furthermore, both TP and LB reduced intestinal cytokine expression and nuclear factor-κ B (NF-κB) mRNA level on Days 56 and 84. In conclusion, long-term treatment of TP and LB improved lipid metabolism and digestive enzymes activities, and affected intestinal inflammatory status, which may be associated with the NF-κB signal.

UII/GPR14 is involved in NF-κB-mediated colonic inflammation in vivo and in vitro

The present study was conducted to investigate the molecular mechanism of urotensin II (UII) and its receptor, G protein‑coupled receptor 14 (GPR14), in colonic inflammation. Urantide, a special antagonist of GPR14, and GPR14-siRNA were used to inhibit GPR14 signaling in dextran sulfate sodium (DSS)‑induced inflammation in mice and Caco-2 cells. The results showed that urantide alleviated rectal bleeding, histological injury and production of interleukin (IL)-17 and tumor necrosis factor‑α (TNF‑α) caused by DSS in mice. GPR14-siRNA transfection subsequent with GPR14 inhibition reduced DSS-induced interferon-γ (IFN)-γ production in Caco-2 cells. Meanwhile, both in vivo and in vitro data demonstrated that inhibition of UII/GPR14 alleviated nuclear factor-κB (NF-κB) activation caused by DSS. In conclusion, UII/GPR14 signaling was involved in the DSS-induced colonic inflammation and its inhibition may serve as a potential therapeutic target, which may be associated with the NF-κB signaling pathway.

The cytotoxicity and protective effects of Astragalus membranaceus extracts and butylated hydroxyanisole on hydroxyl radical-induced apoptosis in fish erythrocytes

Erythrocytes play an essential role in transporting O₂ and CO₂ for respiration in fish. However, erythrocytes continuously suffer from reactive oxygen species (ROS) -induced oxidative stress and apoptosis. Thus, it is essential to expand our knowledge of how to protect erythrocytes against ROS-induced oxidative stress and apoptosis in fish. In this study, we explored the cytotoxicity and the effects of butylated hydroxyanisole (BHA), ethyl ether extracts, ethyl acetate extracts, acetone extracts (AE), ethanol extracts, and aqueous extracts of Astragalus membranaceus (EAm) on hydroxyl radical (•OH)-induced apoptosis in carp erythrocytes. The rat hepatocytes and carp erythrocytes were incubated with different concentrations of BHA or EAm(0.125 to 1 mg/mL). The toxicity in rat hepatocytes and carp erythrocytes was then measured using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and a haemolysis assay, respectively. The carp erythrocytes were treated with BHA or EAm in the presence of 40 μmol/L FeSO₄ and 20 μmol/L H₂O₂ at 37 °C, except for the control group. Oxidative stress and apoptosis parameters in the carp erythrocytes were then evaluated using the commercial kit. The results indicated that at high concentrations, BHA and EAm could induce toxicity in rat hepatocytes and fish erythrocytes. However, BHA was more toxic than EAm at the same concentrations. Moreover, the toxicity order of BHA and EAm in the fish erythrocytes approximately agreed with that for the rat hepatocytes. Butylated hydroxyanisole and EAm suppressed the •OH-induced phosphatidylserine exposure and DNA fragmentation (the biomarkers of apoptosis) by decreasing the generation of ROS, inhibiting the oxidation of cellular components, and restoring the activities of antioxidants in carp erythrocytes. Of all of the examined EAm, the AE showed the strongest effects. The effects of AE on superoxide anion, H₂O₂, met-haemoglobin and reduced glutathione levels, as well as glutathione reductase activity and apoptosis were equivalent to or stronger than those of BHA. These results revealed that the AE of Astragalus membranaceus could be used as a potential natural antioxidant or apoptosis inhibitor in fish erythrocytes.

Hydrogen sulfide improves colonic barrier integrity in DSS-induced inflammation in Caco-2 cells and mice

Intestinal barrier involves in the pathogeny of inflammatory bowel disease (IBD) and hydrogen sulfide (H2S) has been reported to improve intestinal barrier integrity. Thus, this study investigated the effects of GYY4137, a slow-release H2S donor, on DSS-induced inflammation and intestinal dysfunction. In vitro model, cellular permeability was significantly increased and expression of tight junctions (ZO-1, Cauldin4, and Occludin) was downregulated in Caco-2 cells. GYY4137 treatment markedly attenuated DSS-induced inflammation and barrier dysfunction. Cystathionine β-synthase (CBS)-siRNA transfection further demonstrated that endogenous H2S system involves in DSS-induced inflammation and mediates barrier function. In vivo model, DSS exposure caused colonic inflammation and injury in mice and GYY4137 injection alleviated inflammatory response and improved intestinal barrier via reducing intestinal permeability and upregulating of tight junctions. In conclusion, endogenous H2S system involves in DSS-induced inflammation and H2S addition alleviated inflammation and intestinal dysfunction in vitro and in vivo.

N-carbamylglutamate and L-arginine improved maternal and placental development in underfed ewes

The objectives of this study were to determine how dietary supplementation ofN-carbamylglutamate (NCG) and rumen-protected L-arginine (RP-Arg) in nutrient-restricted pregnant Hu sheep would affect (1) maternal endocrine status; (2) maternal, fetal, and placental antioxidation capability; and (3) placental development. From day 35 to day 110 of gestation, 32 Hu ewes carrying twin fetuses were allocated randomly into four groups: 100% of NRC-recommended nutrient requirements, 50% of NRC recommendations, 50% of NRC recommendations supplemented with 20g/day RP-Arg, and 50% of NRC recommendations supplemented with 5g/day NCG product. The results showed that in maternal and fetal plasma and placentomes, the activities of total antioxidant capacity and superoxide dismutase were increased (P<0.05); however, the activity of glutathione peroxidase and the concentration of maleic dialdehyde were decreased (P<0.05) in both NCG- and RP-Arg-treated underfed ewes. The mRNA expression of vascular endothelial growth factor and Fms-like tyrosine kinase 1 was increased (P<0.05) in 50% NRC ewes than in 100% NRC ewes, and had no effect (P>0.05) in both NCG- and RP-Arg-treated underfed ewes. A supplement of RP-Arg and NCG reduced (P<0.05) the concentrations of progesterone, cortisol, and estradiol-17β; had no effect on T4/T3; and improved (P<0.05) the concentrations of leptin, insulin-like growth factor 1, tri-iodothyronine (T3), and thyroxine (T4) in serum from underfed ewes. These results indicate that dietary supplementation of NCG and RP-Arg in underfed ewes could influence maternal endocrine status, improve the maternal–fetal–placental antioxidation capability, and promote fetal and placental development during early-to-late gestation.

Reproductive stage associated changes in plasma fatty acid profile and proinflammatory cytokine expression in rat mammary glands

Mastitis is a common disease for mammals all around the world. Figuring out why mastitis mainly occurs around parturition may be helpful for dealing with the disease. Lipolytic activity and oxidative stress take place around parturition, which may leads to alteration in fatty acids profile and proinflammatory cytokine expression. Thus, the aim of the present study was to further our understanding about the high incidence of mastitis around parturition by comparison of plasma fatty acid profile and mammary inflammation indicators at different reproductive stages. A total of 47 female rats were included in the present study. After mating, all the pregnant and non-pregnant rats began to receive the same experimental diet. Blood samples were collected at day 1 and 14 of gestation as well as day 3 postpartum. Mammary samples were collected at day 14 of gestation and day 3 postpartum from pregnant and non-pregnant rats. The results showed that rats at d 3 postpartum had greater (P < 0.05) plasma concentrations of non-esterified fatty acids (NEFA), arachidonic acid (ARA) and docosahexaenoic acid (DHA) as well as ARA: eicosapentaenoic acid (EPA) ratio than those at d 14 of gestation. The mRNA abundances of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-8 and xanthine oxidoreductase (XOR) in mammary of the pregnant rats were greater (P < 0.05) than those in age-matched non-pregnant rats. Rats at d 3 postpartum had higher (P < 0.05) protein expression levels of IL-1β and TNF-α as well as meloperoxidase (MPO) activity and polymorphonuclear neutrophils (PMN) prevalence than those at d 1 of gestation. The rats at d 3 postpartum also had greater (P < 0.05) IL-1β and MPO activity than those at d 14 of gestation. The results indicated that elevated mammary expression of proinflammatory cytokines and XOR as well as altered fatty acid profile around parturition might facilitate the recruitment of neutrophils into mammary glands.

HOXA13 exerts a beneficial effect in albumin-induced epithelial-mesenchymal transition via the glucocorticoid receptor signaling pathway in human renal tubular epithelial cells

Previous studies have suggested that albumin-induced renal tubular epithelial cell injury contributes to renal interstitial fibrosis. Epithelial-mesenchymal transition (EMT) is known to be a key mechanism in the pathogenesis and progression of renal interstitial fibrosis. Homeobox protein HOX‑A13 (HOXA13) is a nuclear transcriptional factor that has been reported to be involved in renal fibrosis. However, the mechanism underlying the effect of HOXA13 in human serum albumin (HSA)‑induced EMT in HKC renal tubular epithelial cells remains to be elucidated. Thus, the aim of the present study was to investigate the role of HOXA13 in HSA‑induced EMT in HKC cells and the potential mechanism of the glucocorticoid receptor (GR) signaling pathway. The protein and mRNA expression levels of HOXA13, cytokeratin, and vimentin were determined by western blot analysis and reverse transcription‑quantitative polymerase chain reaction in HKC cells, which were co‑incubated with HSA at different concentrations or for different time periods. The results demonstrated that HOXA13 mRNA and protein expression decreased in a dose‑ and time‑dependent manner when induced by HSA in HCK cells. The liposomal transfection experiment suggested that overexpression of HOXA13 activated the GR signal, which inhibits HSA-induced EMT. HOXA13 is involved in HSA‑induced EMT in HKC cells and upregulation of HOXA13 exerts a beneficial effect in EMT, which may be associated with the GR signaling pathway.

Inhibition of lipid oxidation in foods and feeds and hydroxyl radical-treated fish erythrocytes: A comparative study of Ginkgo biloba leaves extracts and synthetic antioxidants

This study explored the effects of butylated hydroxytoluene (BHT) and ethoxyquin (EQ) and ethyl ether extracts, ethyl acetate extracts (EAE), acetone extracts, ethanol extracts and aqueous extracts of Ginkgo biloba leaves (EGbs) on lipid oxidation in a linoleic acid emulsion, fish flesh and fish feed and in hydroxyl radical (·OH)-treated carp erythrocytes. The linoleic acid, fish flesh and fish feed were incubated with BHT, EQ and EGbs at 45°C for 8 d, respectively, except for the control group. The lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed was then measured by the ferric thiocyanate method or thiobarbituric acid method. The carp erythrocytes were treated with BHT, EQ or EGbs in the presence of 40 μmol/L FeSO₄ and 20 μmol/L H₂O₂ at 37°C for 6 h, except for the control group. Oxidative stress and apoptosis parameters in carp erythrocytes were then evaluated by the commercial kit. The results showed that BHT, EQ and EGbs inhibited lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed and ·OH-induced phosphatidylserine exposure and DNA fragmentation (the biomarkers of apoptosis) in carp erythrocytes. Furthermore, BHT, EQ and EGbs decreased the generation of reactive oxygen species (ROS), inhibited the oxidation of cellular components and restored the activities of enzymatic antioxidants in ·OH-treated carp erythrocytes. Of all examined EGbs, EAE showed the strongest effects. The effects of EAE on lipid oxidation in the linoleic acid emulsion and on superoxide anion and malonaldehyde levels, catalase activity and apoptosis in ·OH-treated carp erythrocytes were equivalent to or stronger than those of BHT. Moreover, these results indicated that the inhibition order of EGbs on the generation of ROS and oxidation of cellular components in fish erythrocytes approximately agreed with that for the food and feed materials tested above. And, the antioxidative and anti-apoptotic effects of EGbs were positively correlated with their flavonoid content. Taken together, these results revealed that the fish erythrocyte system can be used as an experimental model to evaluate lipid oxidation in food and feed ingredients. The EAE can be used as a potential natural antioxidant or apoptosis inhibitor. The inhibition effects of EGbs on lipid oxidation and apoptosis may be due to the presence of flavonoid compounds.

NaHS inhibits NF-κB signal against inflammation and oxidative stress in post-infectious irritable bowel syndrome

In this study, the alleviating role of hydrogen sulfide (H₂S) was investigated in a Post-Infectious Irritable Bowel Syndrome (PI-IBS) murine model and Caco-2 cells.

Endoplasmic Reticulum Stress in Heat- and Shake-Induced Injury in the Rat Small Intestine

We investigated the mechanisms underlying damage to rat small intestine in heat- and shake-induced stress. Eighteen Sprague-Dawley rats were randomly divided into a control group and a 3-day stressed group treated 2 h daily for 3 days on a rotary platform at 35°C and 60 r/min. Hematoxylin and eosin-stained paraffin sections of the jejunum following stress revealed shedding of the villus tip epithelial cells and lamina propria exposure. Apoptosis increased at the villus tip and extended to the basement membrane. Photomicrographs revealed that the microvilli were shorter and sparser; the nuclear envelope invaginated and gaps in the karyolemma increased; and the endoplasmic reticulum (ER) swelled significantly. Gene microarray analysis assessed 93 differentially expressed genes associated with apoptosis, ER stress, and autophagy. Relevant genes were compiled from the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Forty-one genes were involved in the regulation of apoptosis, fifteen were related to autophagy, and eleven responded to ER stress. According to KEGG, the apoptosis pathways, mitogen-activated protein kinase(MAPK) signaling pathway, the mammalian target of rapamycin (mTOR) signaling pathway, and regulation of autophagy were involved. Caspase3 (Casp3), caspase12 (Casp12), and microtubule-associate proteins 1 light chain 3(LC3) increased significantly at the villus tip while mTOR decreased; phosphorylated-AKT (P-AKT) decreased. ER stress was involved and induced autophagy and apoptosis in rat intestinal damage following heat and shake stress. Bioinformatic analysis will help determine the underlying mechanisms in stress-induced damage in the small intestine.

Pyrrolidine Dithiocarbamate Inhibits NF-KappaB Activation and Upregulates the Expression of Gpx1, Gpx4, Occludin, and ZO-1 in DSS-Induced Colitis

Inflammatory bowel disease (IBD) correlates with oxidative stress, inflammation, and alteration in several signal pathways, including nuclear transcription factor-kappaB (NF-κB). Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, has been widely demonstrated to exhibit an antioxidant and anti-inflammatory function. This study aimed to test the hypothesis that NF-κB inhibitor PDTC confers a beneficial role in a colitis model induced by dextran sodium sulfate (DSS) in mouse. The results showed that DSS decreased daily weight gain, induced colonic inflammation, suppressed the expression of antioxidant enzymes and tight junctions, and activated NF-κB and nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathways. PDTC significantly upregulated (P < 0.05) Gpx1, Gpx4, occludin, and ZO-1 expressions in the DSS-induced colitis model. Meanwhile, PDTC reversed (P < 0.05) the activation of NF-κB signal pathway caused by DSS treatment. In conclusion, PDTC could serve as an adjuvant therapy for the patient with IBD.

Effects of the Sequence of Isocaloric Meals with Different Protein Contents on Plasma Biochemical Indexes in Pigs

Nutrient composition and pattern of food intake may play a significant role in weight gain. The aim of this study was to document the effects of a daily 3-meal pattern with isocaloric diets containing different dietary protein contents on growth performance and different plasma biochemical indexes including amino acid plasma concentration in castrated male pigs. Then, 21 DLY (Duroc×Landrace×Yorkshire) pigs aged 60 days were assigned randomly into 3 groups: a control group (crude protein, CP 18.1%), a group receiving high then basal and then low CP meals (High-Low group) and a group receiving low then basal and then high CP meal (Low-High group) for 40 days with pigs being feed-restricted. On day 40, after 12 h fasting, blood samples were obtained for analysis. The results showed that the insulin/glucagon ratio was lower in the High-Low group (P<0.05) when compared with the control group. Compared with the control group, the average daily gain of pigs from the High-Low group increased by 14.10% (P = 0.046). Compared with the control group, serum gamma-glutamyl transferase (GGT) decreased significantly (P<0.05) in both the High-Low and Low-High groups. Plasma concentrations of branched-chain amino acids (BCAA: valine, isoleucine and leucine) increased in the Low-High group (P<0.05) when compared with the control group; and plasma methionine and serine decreased in both the two experimental groups (P<0.05). Compared with the High-Low group, all the BCAA increased significantly (P<0.05) in the Low-High group. These findings suggest that the sequence and quantity of alimentary protein intake affect the insulin/glucagon ratio, as well as amino acid concentrations including BCAA, methionine and serine. It is proposed that meal pattern with pigs receiving high then basal and then low CP meals daily may help to improve the weight gain of pigs.

Co-dependence of genotype and dietary protein intake to affect expression on amino acid/peptide transporters in porcine skeletal muscle

A total of 96 barrows (48 pure-bred Bama mini-pigs representing fatty genotype, and 48 Landrace pigs representing lean genotype) were randomly assigned to either a low- or adequate-protein treatment diet. The experimental period commenced at 5 weeks of age and extended to the finishing period. After euthanasia, blood and skeletal muscle samples were collected from pigs at the nursery, growing, and finishing phases. Our results indicate that the concentrations of free AAs in the plasma and muscle decreased as the age of the pigs increased. In addition, a strain × growth phase interaction (P < 0.05) was observed for the free AA pool in the plasma and muscle. The low-protein diet upregulated (P < 0.05) the mRNA levels for T1R1/T1R3 involved in glutamate binding, but downregulated (P < 0.05) the mRNA levels for PAT1, PAT2, and ASCT2, which transport neutral AAs into muscles. Bama mini-pigs had higher (P < 0.05) mRNA levels for LAT1, SNAT2, and EAAC1, but a lower (P < 0.05) mRNA level for PepT1, compared with Landrace pigs. Collectively, our findings indicate that adequate provision of dietary protein plays an important role in regulating profiles of free AA pools and expression of key AA/peptide transporters/transceptors in a genotype- and tissue-specific manner.

Dietary supplementation with L-glutamate and L-aspartate alleviates oxidative stress in weaned piglets challenged with hydrogen peroxide

This study was to evaluate the protective roles of L-glutamate (Glu) and L-aspartate (Asp) in weaned piglets challenged with H2O2. Forty weaned piglets were assigned randomly into one of five groups (8 piglets/group): (1) control group (NC) in which pigs were fed a corn- and soybean meal-based diet and received intraperitoneal administration of saline; (2) H2O2 group (PC) in which pigs were fed the basal diet and received intraperitoneal administration of 10 % H2O2 (1 ml/kg body weight once on days 8 and repeated on day 11); (3) PC + Glu group (PG) in which pigs were fed the basal diet supplemented with 2.0 % Glu before intraperitoneal administration of 10 % H2O2; (4) PC + Asp group (PA) in which pigs were fed the basal diet supplemented with 1.0 % Asp before intraperitoneal administration of 10 % H2O2; (5) PC + Glu + Asp group (PGA) in which pigs were fed the basal diet supplemented with 2.0 % Glu plus 1.0 % Asp before intraperitoneal administration of 10 % H2O2. Measured parameters included daily feed intake (DFI), average daily gain (ADG), feed conversion rate (FCR), and serum anti-oxidative enzyme activities (catalase, superoxide dismutase, glutathione peroxidase-1), serum malondialdehyde and H2O2 concentrations, serum amino acid (AA) profiles, and intestinal expression of AA transporters. Dietary supplementation with Glu, Asp or their combination attenuated the decreases in DFI, ADG and feed efficiency, the increase in oxidative stress, the alterations of serum AA concentrations, and the changed expression of intestinal AA transporters in H2O2-challenged piglets. Thus, dietary supplementation with Glu or Asp alleviates growth suppression and oxidative stress, while restoring serum the amino acid pool in H2O2-challenged piglets.

Preinduction of heat shock protein 70 protects mice against post-infection irritable bowel syndrome via NF-κB and NOS/NO signaling pathways

This study aimed to investigate the protective effects of preinduction of heat shock protein 70 (HSP70) on Trichinella spiralis infection-induced post-infectious irritable bowel syndrome (PI-IBS) in mice. Trichinella spiralis infection significantly reduced HSP70 abundance, ileal villus height and crypt depth, expression of tight junctions, serum lysine and arginine concentrations, and ileal SCL7A6 and SCL7A7 mRNA levels, induced inflammatory response, and activated NF-κB signaling pathway. Meanwhile, the heat treatment upregulated HSP70 expression, and then reversed intestinal dysfunction and inflammatory response. Preinduction of HSP70 enhanced serum arginine and intestinal SCL7A7 expression and inhibited NF-κB activation compared with PI-IBS model. Treatment with pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor) and N-nitro-L-arginine methyl ester hydrochloride (L-NAME, a nitric oxide synthase inhibitor, NOS) further demonstrated that preinduction of HSP70 might inhibit NF-κB and activated NOS/nitric oxide (NO) signaling pathways. In conclusion, preinduction of HSP70 by heat treatment may confer beneficial effects on Trichinella spiralis infection-induced PI-IBS in mice, and the protective effect of HSP70 may be associated with inhibition of NF-κB and stimulation of NOS/NO signaling pathways.