Protective effects of oral glutathione on fasting-induced intestinal atrophy through oxidative stress

Lycibarbarspermidine L from the fruit of Lycium barbarum L. recovers intestinal barrier damage via regulating miR-195-3p

ETHNOPHARMACOLOGICAL RELEVANCE

The fruit of Lycium barbarum L. is widely employed with the traditional effect of tonic properties. According to the theory of traditional Chinese medicine, Gou Qi can be distributed in the meridian of stomach, as well as the liver and kidney, indicating its effect on the digestive system. Clinical studies found that Gou Qi enhanced gastrointestinal functions. Pharmacological research showed the extract of Lycium barbarum exhibiting a repaired effect on the intestine barrier. Lycibarbarspermidine L (LBS L), which belongs to polyamines, is separated from the fruit of Lycium barbarum. However, it is unknown whether LBS L can restore damaged intestinal barrier like other polyamines such as spermidine.

AIM OF THE STUDY

To elucidate the recovery effect of LBS L on damaged intestinal epithelium and its miRNA-related mechanism.

MATERIALS AND METHODS

IEC-6 cells were used in vitro to assess the therapeutic effect of LBS L on the injured intestine and the regulation of miR-195-3p. Spermidine (SPD) with intestinal mucosal repair effect was used as a positive control. Sprague Dawley (SD) rats were subjected to 48 h fasting to induce intestinal epithelial atrophy in vivo. To determine the therapeutic effect of LBS L on injured intestinal epithelium and explore the mechanism, the fasting model group rats were treated with LBS L (25 mg/kg) for 4 days.

RESULTS

Results in vitro showed that LBS L (10 μM) promoted cell proliferation and migration, affecting the S phase of the cell cycle. Western blot signals showed that LBS L raised the expression level of occludin. The miR-195-3p levels were decreased following LBS L treatment, which could be inversed by transfecting miR-195-3p mimic, demonstrating that LBS L inhibited miR-195-3p to improve cell growth. Results in vivo showed that LBS L could reverse the atrophic villi and inflammatory cell infiltration in the submucosa and restore miR-195-3p, occludin, and Ki67 levels in the intestine of mice in the fasting group.

CONCLUSIONS

LBS L restores injured intestinal epithelium by reducing the expression of miR-195-3p.

Effects of different selenium sources on duodenum and jejunum tight junction network and growth performance of broilers in a model of fluorine-induced chronic oxidative stress

The protective effects and underlying molecular mechanisms of sodium selenite (SS) and selenomethionine (SM) against chronic oxidative stress-induced duodenum and jejunum tight junction (TJ) network disturbance and growth inhibition of broilers were investigated in the current experiment. At the age of 1 d, 720 Lingnan Yellow broiler chicks were allocated to 4 experimental diets (with 6 replicates per diet and 30 birds per replicate) and offered either a control diet (fluorine [F] 23 mg/kg, control [CoN] group) or test diets (800 mg/kg F, high F [HF] group; 800 mg/kg F+0.15 mg selenium [Se]/kg as SS [SS group] or SM [SM group]) for 56 d. The results showed that HF group could induce chronic oxidative stress and subsequently increased (P < 0.05) proinflammatory cytokines levels of duodenum and jejunum in comparison with the CoN group. Increased proinflammatory cytokines levels of HF group promoted myosin light chain kinase (MLCK) transcription, thus leading to a decrease (P < 0.05) in TJ proteins expression of duodenum and jejunum when compared with the CoN group. A reduction of TJ proteins expression destroyed the TJ structures in the HF group, which in turn increased intestinal mucosal permeability of duodenum and jejunum and ultimately induced growth inhibition of broilers. Dietary Se supplementation could ameliorate HF-induced duodenum and jejunum TJ network impairment and growth retardation of broilers, potentially by increasing (P < 0.05) the glutathione peroxidase and thioredoxin reductase activities, reducing (P < 0.05) the reactive oxygen species and malondialdehyde levels, regulating the secretion of proinflammatory cytokines, and mediating the transcription level of MLCK in the duodenum and jejunum. Additionally, our data also suggested that the protective effects of SM were superior to those of SS. This study will provide a theoretical basis for developing SM into an efficient protective agent for intestinal mucosal barrier in poultry.

Impact of Different Durations of Fasting on Intestinal Autophagy and Serum Metabolome in Broiler Chicken

Simple Summary

Fasting is usually used before metabolizable energy assessment in poultry. Recently, fasting-induced autophagy has been of concern because of the beneficial function of autophagy. In this study, we found that the intestinal autophagy gene Atg7 has a good quadratic fitting with fasting duration. We found that the serum metabolism pathways involved in glycerophospholipid, phenylalanine, GnRH signaling pathways, glycosylphosphatidylinositol anchor biosynthesis, autophagy, and ferroptosis changed with fasting. Furthermore, we found a correlation between intestinal autophagy and serum metabolite PE (18:3(9Z,12Z,15Z)/P-18:0).

Abstract

Fasting-induced autophagy in the intestine is beneficial for body health. This study was designed to explore the relationship between the host metabolism and intestinal autophagy. Broilers were randomly assigned into 48 cages. At 0 (CT), 12 (FH12), 24 (FH24), 36 (FH36), 48(FH48), and 72 h (FH72) before 09:00 a.m. on day 25, eight cages of birds were randomly allotted to each fasting time point using completely random design, and their food was removed. At 09:00 a.m. on day 25, the blood and jejunum were sampled for serum metabolome and autophagy gene analyses, respectively. The results showed that the autophagy gene Atg7 has a good quadratic fit with fasting duration (R² = 0.432, p < 0.001). Serum phosphatidylethanolamine (PE) and lyso-PE were decreased in the birds that were fasted for 24 h or longer. Conversely, the serum phosphatidylcholine (PC) and lyso-PC were increased in the birds that were fasted for 36 h or longer. Metabolism pathway analysis showed that the serum glycerophospholipid, phenylalanine, and GnRH signaling pathways were downregulated with the extended fasting duration. The serum metabolites involved in glycosylphosphatidylinositol anchor biosynthesis, autophagy, and ferroptosis were upregulated in all of the fasted groups. Correlation analysis showed that serum PE (18:3(9Z,12Z,15Z)/P-18:0) was a potential biomarker for intestinal autophagy. Our findings provide a potential biomarker related to intestinal autophagy.

Renalase is localized to the small intestine crypt and expressed upon the activation of NF-κB p65 in mice model of fasting-induced oxidative stress

AIMS

Renalase expression is regulated by Nuclear Factor (NF)-κB and hypoxia inducible factor (HIF)-1α, and antioxidative stress function in renal cells were reported. However, dynamics of renalase and localizes in intestine were remain unknown. We evaluated the effects of oxidative stress on renalase expression and localization using model of fasting induced oxidative stress and Caco-2 cell, and examined the its physiological effects.

MAIN METHODS

24 male mice were divided into three groups: Control (Con), 72 h fasting (Fast), and 24 h refeeding after fasting (Refeed). Jejunum and ileum were collected respectively. The structure of jejunum and ileum were observed by hematoxylin and eosin (HE) stain. The expression levels of carbonylated protein, renalase, NF-κB p65 and HIF-1α were measured by immunoblotting. Localization of renalase was observed by immunofluorescent. in vitro assay was performed using Caco-2 cell. Renalase was overexpressed using adenovirus. After that, Caco-2 cell was treated with 2 mM H₂O₂ for 30 min or 24 h.

KEY FINDINGS

Renalase was increased in Fast and it was localized in crypt. HIF-1α did not increase, but NF-κB p65 increased in Fast. Renalase overexpression protects the Caco-2 cells against H₂O₂ induced oxidative stress.

SIGNIFICANCE

Renalase was localized in crypt and increased in Fast. This increase suggested protect response to oxidative stress because undifferenced cells were localized in crypt and need to be protected. Actually, renalase protected Caco-2 cells against H₂O₂ induced oxidative stress. Small intestinal renalase expression was regulated by NF-κB p65 and was considered to be a defense mechanism against oxidative stress.

Fructose Consumption by Adult Rats Exposed to Dexamethasone In Utero Changes the Phenotype of Intestinal Epithelial Cells and Exacerbates Intestinal Gluconeogenesis

Fructose consumption by rodents modulates both hepatic and intestinal lipid metabolism and gluconeogenesis. We have previously demonstrated that in utero exposure to dexamethasone (DEX) interacts with fructose consumption during adult life to exacerbate hepatic steatosis in rats. The aim of this study was to clarify if adult rats born to DEX-treated mothers would display differences in intestinal gluconeogenesis after excessive fructose intake. To address this issue, female Wistar rats were treated with DEX during pregnancy and control (CTL) mothers were kept untreated. Adult offspring born to CTL and DEX-treated mothers were assigned to receive either tap water (Control-Standard Chow (CTL-SC) and Dexamethasone-Standard Chow (DEX-SC)) or 10% fructose in the drinking water (CTL-fructose and DEX-fructose). Fructose consumption lasted for 80 days. All rats were subjected to a 40 h fasting before sample collection. We found that DEX-fructose rats have increased glucose and reduced lactate in the portal blood. Jejunum samples of DEX-fructose rats have enhanced phosphoenolpyruvate carboxykinase (PEPCK) expression and activity, higher facilitated glucose transporter member 2 (GLUT2) and facilitated glucose transporter member 5 (GLUT5) content, and increased villous height, crypt depth, and proliferating cell nuclear antigen (PCNA) staining. The current data reveal that rats born to DEX-treated mothers that consume fructose during adult life have increased intestinal gluconeogenesis while recapitulating metabolic and morphological features of the neonatal jejunum phenotype.

Glycyrrhetinic Acid Maintains Intestinal Homeostasis via HuR

Glycyrrhetinic acid (GA) is one of the main components of the traditional Chinese medicine of licorice, which can coordinate and promote the effects of other medicines in the traditional prescription. We found that GA could promote the proliferation, decrease the apoptotic rate, and attenuate DFMO-elicited growth arrest and delay in restitution after wounding in IEC-6 cells via HuR. GA failed to promote proliferation and to suppress apoptosis after silencing HuR by siRNA in IEC-6 cells. Furthermore, with the model of small intestinal organoids developed from intestinal crypt stem cells, we found that GA could increase HuR and its downstream ki67 levels to promote intestinal organoid development. In the in vivo assay, GA was shown to maintain the integrity of the intestinal epithelium under the circumstance of 48 h-fasting in rats via raising HuR and its downstream genes such as EGF, EGFR, and MEK. These results suggested that via HuR modulation, GA could promote intestinal epithelium homeostasis, and therefore contribute to the absorption of constituents from other medicines co-existing in the traditional prescription with licorice in the small intestine. Our results provide a new perspective for understanding the effect of licorice on enhancing the therapeutic effect of traditional prescriptions according to the traditional Chinese medicine theory.

Effects of N-Acetyl-Cysteine Supplementation through Drinking Water on the Glutathione Redox Status during the Weaning Transition of Piglets

This study investigated the effect of N-acetyl-cysteine (NAC) supplementation through drinking water on animal performance and the glutathione (GSH) redox system in weaned piglets, particularly in relation to the immediate post-weaning feed intake. To this end, 168 piglets were weaned and either fed ad libitum or fasted the first two days, and either or not administered 200 mg/L NAC via the drinking water until d14 post-weaning. Next to animal performance until day 42 (d42), the GSH redox system was measured in erythrocytes, small intestinal mucosa, liver, lung, and kidney tissue at d0, d2, and d14 post-weaning. Animal performance and GSH levels were not affected by NAC, nor by fasting. Irrespective of treatment, a significant drop in GSH at d2 post-weaning was found as compared to d0, in particular in liver (−69%), distal jejunal mucosa (−72%), and lung tissue (−80%). Post-weaning changes of the GSH redox status were strongly tissue-dependent. To conclude, this research indicates that GSH redox homeostasis was largely affected in multiple organs during the weaning transition. NAC supplementation did not increase GSH levels in any tissue, not even in fasted animals, questioning the fact if cysteine is the first or only limiting factor determining the rate of GSH synthesis in the early post-weaning phase.