Effect of fat feeding on pro-oxidant and anti-oxidant enzyme systems in rat intestine: possible role in the turnover of enterocytes

Effects of Equol Supplementation on Growth Performance, Redox Status, Intestinal Health and Skeletal Muscle Development of Weanling Piglets with Intrauterine Growth Retardation

Animals with intrauterine growth retardation (IUGR) usually undergo injured postnatal growth and development during the early period after birth. Equol (Eq), an isoflavan produced by gut bacteria in response to daidzein intake, has various health benefits. Therefore, the objective of this study was to evaluate whether Eq supplementation can influence the growth performance, redox status, intestinal health and skeletal muscle development of weanling piglets with IUGR. A total of 10 normal-birth-weight (NBW) newborn female piglets and 20 newborn female piglets with IUGR were selected. After weaning at the age of 21 d, 10 NBW piglets and 10 IUGR piglets were allocated to the NBW group and IUGR group, respectively, and offered a basal diet. The other 10 IUGR piglets were allocated to the IUGR + Eq group and offered a basal diet with 50 mg of Eq per kg of diet. The whole trial lasted for 21 d. At the end of the feeding trial, all piglets were sacrificed for the collection of serum, intestinal tissues and skeletal muscles. Supplementation with Eq increased the average daily gain (ADG), average daily feed intake (ADFI), duodenal villus height to crypt depth ratio (V/C), jejunal villus height and V/C, but reduced the duodenal crypt depth in neonatal piglets with IUGR. Meanwhile, Eq supplementation elevated the activities of superoxide dismutase (SOD) and catalase (CAT) in the serum and duodenum and the activity of SOD in the jejunum, but lowered malondialdehyde (MDA) content in the serum, jejunum and ileum of piglets with IUGR. In addition, supplementation with Eq reduced diamine oxidase (DAO) activity and the levels of D-lactate and endotoxin in serum, and the tumor necrosis factor-α (TNF-α) level in jejunum and ileum, whereas the concentration of serum immunoglobulin G (IgG) and the mRNA levels of intestinal barrier-related markers in jejunum and ileum of IUGR piglets were increased. Furthermore, supplementation with Eq elevated the percentage of fast-fibers and was accompanied with higher mRNA expression of myosin heavy chain IIb (MyHC IIb) and lower mRNA levels in MyHC I in the longissimus thoracis (LT) muscle of IUGR piglets. In summary, Eq supplementation can promote antioxidant capacity, maintain intestinal health and facilitate skeletal muscle development, thus resulting in the higher growth performance of IUGR piglets.

Mitochondrial function in intestinal epithelium homeostasis and modulation in diet-induced obesity

Background

Systemic low-grade inflammation observed in diet-induced obesity has been associated with dysbiosis and disturbance of intestinal homeostasis. This latter relies on an efficient epithelial barrier and coordinated intestinal epithelial cell (IEC) renewal that are supported by their mitochondrial function. However, IEC mitochondrial function might be impaired by high fat diet (HFD) consumption, notably through gut-derived metabolite production and fatty acids, that may act as metabolic perturbators of IEC.

Scope of review

This review presents the current general knowledge on mitochondria, before focusing on IEC mitochondrial function and its role in the control of intestinal homeostasis, and featuring the known effects of nutrients and metabolites, originating from the diet or gut bacterial metabolism, on IEC mitochondrial function. It then summarizes the impact of HFD on mitochondrial function in IEC of both small intestine and colon and discusses the possible link between mitochondrial dysfunction and altered intestinal homeostasis in diet-induced obesity.

Major conclusions

HFD consumption provokes a metabolic shift toward fatty acid β-oxidation in the small intestine epithelial cells and impairs colonocyte mitochondrial function, possibly through downstream consequences of excessive fatty acid β-oxidation and/or the presence of deleterious metabolites produced by the gut microbiota. Decreased levels of ATP and concomitant O₂ leaks into the intestinal lumen could explain the alterations of intestinal epithelium dynamics, barrier disruption and dysbiosis that contribute to the loss of epithelial homeostasis in diet-induced obesity. However, the effect of HFD on IEC mitochondrial function in the small intestine remains unknown and the precise mechanisms by which HFD induces mitochondrial dysfunction in the colon have not been elucidated so far.

Dietary chlorogenic acid supplementation affects gut morphology, antioxidant capacity and intestinal selected bacterial populations in weaned piglets

Chlorogenic acid (CGA), an ester formed between caffeic acid and quinic acid, is one of the most abundant phenolic acids and is widespread in fruits, vegetables, cereals and tuber crops. Therefore, the present study was conducted to test the hypothesis that dietary supplementation with CGA could improve intestinal health and regulate intestinal selected microbiota in weaned piglets. A total of twenty-four piglets (21 d of age) were randomly assigned to one of four groups according to their initial BW and sex and fed a basal diet (control group) or a basal diet containing 250, 500 and 1000 mg kg-1 CGA, respectively. The whole trial lasted for 28 d. Dietary CGA supplementation increased (P < 0.05) the duodenal villous height and villous height : crypt depth ratio, but decreased (P < 0.05) the F/G ratio and duodenal crypt depth when compared with the control group. Meanwhile, an increase (P < 0.05) in the jejunal villous height and in the ileal villous height : crypt depth ratio were also observed in CGA-fed piglets. Supplementation with CGA significantly increased (P < 0.05) the activity of serum GSH-Px and the activities of duodenal GSH-Px and CAT, upregulated (P < 0.05) the expression of OCLN in the duodenum and jejunum, and decreased (P < 0.05) the ileal MDA content when compared to the control group. In addition, an increase (P < 0.05) in the population of Lactobacillus and a decrease (P < 0.05) in the population of Escherichia coli were observed in the colon of pigs fed CGA diets. Furthermore, pigs fed CGA diets had higher (P < 0.05) propionic and butyric acid concentrations in the colon. Altogether, our results provide evidence that dietary CGA is beneficial for preserving intestinal morphological integrity and selectively regulating intestinal microbiota, which can provide a means to improve gut health and growth performance post-weaning.

The effects of dietary sulfur amino acids on growth performance, intestinal morphology, enzyme activity, and nutrient transporters in weaning piglets

Early weaning results in intestinal dysfunction in piglets, while sulfur amino acids (SAA) are involved in improving intestinal functions. We tested a hypothesis that dietary supplementation with SAA can improve intestinal functions of weaning piglets and analyzed the effects of different dietary SAA levels on intestinal functions. A total of 80 piglets (Duroc × Landrace × Yorkshire) were weaned at 21 d of age and randomly assigned to one of the five diets that contained 0.53%, 0.63%, 0.74%, 0.85%, or 0.96% SAA, which corresponded to 70%, 85%, 100%, 115%, or 130% of the SAA:Lys ratio recommended by the National Research Council (2012). The 14 d feeding experiment involved 16 pens per diet and one piglet per pen. Eight randomly selected piglets from each treatment were euthanized for tissue sampling on day 7 and 14 post weaning. Supplementation with SAA led to a rise over time in G:F (linear, P = 0.001; quadratic, P = 0.001). Between day 0 and 14 of treatment, the jejunal crypt depth decreased (linear, P = 0.018; quadratic, P = 0.015), while that of the duodenal villus (linear, P = 0.049) and ileal villus width (linear, P = 0.029; quadratic, P = 0.034) increased. The activities of jejunal alkaline phosphatase (ALP) were quadratically increased (P = 0.040) from day 0 to 14 due to dietary SAA. Dietary SAA also elevated the activities of jejunal lactase (linear, P = 0.003; quadratic, P = 0.004), jejunal sucrase (linear, P = 0.032; quadratic, P = 0.027), and jejunal contents of glutathione (GSH) from day 0 to 7, as well as the activity of jejunal maltase (linear, P = 0.014; quadratic, P = 0.001) between day 0 and 14. During the first wk, dietary SAA linearly increased the amounts of intestinal-type fatty acid-binding protein (I-FABP) (P = 0.048) and SGLT-1 (P = 0.021) and linearly decreased the amount of GLUT2 (P = 0.029) proteins in the jejunum. The abundance of jejunal I-FABP (P = 0.044) and PEPT1 (P = 0.049) protein linearly increased from day 0 to 14 in response to this supplementation. These findings indicate that there is a dose-dependent response to dietary SAA on feed efficiency and intestinal parameters of weanling pigs.

Ischemic Postconditioning Assessment in the Liver of Rats Undergoing Mesenteric Ischemia and Reperfusion

Introduction

Ischemic postconditioning is a method that shows evidence of efficacy in minimizing reperfusion injury; however, its effectiveness in preventing injuries in distant organs is still unknown, especially in those who have undergone mesenteric ischemia and reperfusion.

Objective

To evaluate the effect of ischemic postconditioning in preventing reperfusion injury in the liver of rats submitted to mesenteric ischemia and reperfusion, comparing two different methods of ischemic postconditioning.

Methods

30 Wistar male rats were used, distributed into three groups: Group A: Ten rats submitted to intestinal ischemia for 30 minutes followed by reperfusion for 60 minutes; Group B: Ten rats subjected to ischemia and reperfusion; after ischemia, two cycles of reperfusion (two minutes each) interleaved with two cycles of ischemia (two minutes each); and Group C: Ten rats subjected to ischemia and reperfusion; after ischemia, four cycles of reperfusion (30 seconds each) interspersed with four cycles of ischemia (30 seconds each). After the experiment, the left lobe of the liver was resected for subsequent histological analysis, using the following classification: grade 1 - centrilobular congestion; grade 2 - centrilobular congestion with some degeneration of hepatocytes in one or two central veins; and grade 3 - multifocal centrilobular congestion and degeneration of portal hepatocytes.

Results

The mean degree of liver damage found was 1.8 in group A, 1.7 in group B and 1.3 in group C. There was no statistically significant difference between the groups.

Conclusion

Ischemic postconditioning was unable to minimize reperfusion injury in rats undergoing mesenteric ischemia and reperfusion.

Effect of antioxidant supplementation on digestive enzymes in radiation induced intestinal damage in rats

PURPOSE

Intestinal mucosa, a rapidly proliferating tissue, is highly sensitive to radiation and undergoes apoptosis as a consequence of over generation of oxidative free radicals and the lack of the antioxidants. Thus the present study was designed to investigate the intestinal damage induced by radiation and to study if supplementation of the diet with antioxidant vitamins could ameliorate the intestinal damage and its digestive activity, as determined by the expression of various border enzymes.

MATERIALS AND METHODS

Swiss Albino rats (150-200 g body weight) were divided into six groups. Group I: Control untreated; Group II: Irradiated; Group III: Irradiated + vitamin A; Group IV: Irradiated + vitamin C; Group V: Irradiated + vitamin E; and Group VI: Irradiated + lycopene. Animals were exposed to whole body γ-radiation from (60)Co at the rate of 8 Gy for 15 min/rat. Intestinal morphology and changes in various digestive enzymes together with, DNA damage was studied in six groups and each group consisted of 18 animals.

RESULTS

The gastrointestinal toxicity resulted in malabsorption, diarrhoea, weight loss, loss of appetite, abdominal haemorrhage and hair loss. The activities of sucrase and alkaline phosphatase were elevated and those of lactase, leucine aminopeptidase (LAP) and gamma-glutamyl transpeptidase or tranferase (γ-GTP) were markedly reduced. Antioxidant vitamin A, C or E supplementations prevented changes in brush border enzyme activities as compared to lycopene administration in rat intestine by radiation exposure. Intestinal histology showed that the vitamin supplementation to irradiated rats minimized the intestinal damage in rats.

CONCLUSION

These findings suggest that the epithelial lining of the intestine is highly sensitive to radiation exposure and supplementation of antioxidant vitamins is helpful in minimizing the intestinal damage and supplementation by vitamin E was most potent in ameliorating the intestinal aberrations.

Peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC1alpha) is a metabolic regulator of intestinal epithelial cell fate

Peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC1α) is a transcriptional coactivator able to up-regulate mitochondrial biogenesis, respiratory capacity, oxidative phosphorylation, and fatty acid β-oxidation with the final aim of providing a more efficient pathway for aerobic energy production. In the continuously renewed intestinal epithelium, proliferative cells in the crypts migrate along the villus axis and differentiate into mature enterocytes, increasing their respiratory capacity and finally undergoing apoptosis. Here we show that in the intestinal epithelial surface, PGC1α drives mitochondrial biogenesis and respiration in the presence of reduced antioxidant enzyme activities, thus determining the accumulation of reactive oxygen species and fostering the fate of enterocytes toward apoptosis. Combining gain- and loss-of-function genetic approaches in human cells and mouse models of intestinal cancer, we present an intriguing scenario whereby PGC1α regulates enterocyte cell fate and protects against tumorigenesis.

Flaxseed, olive and fish oil influence plasmatic lipids, lymphocyte migration and morphometry of the intestinal of Wistar rats

PURPOSE

Evaluate the effect of flaxseed, olive and fish oil on the lipid profile, preservation of villosities and lymphocyte migration in the intestinal mucosa of Wistar rats.

METHODS

Thirty Wistar male rats were divided into four groups, which received the AIN-93M diet, with changes only to their lipid source: flaxseed, olive, fish, and soy oil (control group). The serum was separated for the biochemical parameter analysis. A histological evaluation was performed in the ileal portion.

RESULTS

The group which was fed fish oil presented lower values when compared to the other treatments for Total Cholesterol, High-density Lipoprotein Cholesterol and Triacylglycerol (p<0.05). The animals treated with fish and olive oils presented better intestinal villosities preservation. Less deposition of lymphocytes was observed in the flaxseed group (p<0.001).

CONCLUSIONS

This study demonstrated that flaxseed, olive and fish oils present different responses than soy oil for the intestinal mucosa preservation and lymphocyte proliferation in Wistar rats.

Effects of spray-dried animal plasma on serous and intestinal redox status and cytokines of neonatal piglets

The study investigated the effects of dietary supplementation with spray-dried animal plasma (SDAP) on growth performance, intestinal morphology, as well as serum and intestinal cytokines and antioxidant indicators of artificially reared neonatal piglets. Three diets, 1) control (a fish meal basal diet), 2) SDAP (containing 10% SDAP), and 3) autoclaved SDAP (auSDAP; containing 10% auSDAP), were fed to 36 weaned piglets (3 d old), which were randomly allotted to 3 groups. At 21 d of age, blood and intestinal mucosal samples were collected from all piglets after they were slaughtered. Compared with the control, both SDAP and auSDAP improved ADFI and duodenal villus height of piglets (P < 0.05), whereas SDAP increased ADG and duodenal villus height to crypt depth ratio (P < 0.05). Piglets fed SDAP and auSDAP had reduced malondialdehyde (MDA) content in mucosa (P < 0.05). The concentration of serum MDA was decreased and mucosal catalase (CAT) activities were increased in piglets fed SDAP diet than those fed the control diet (P < 0.05). In the mucosa, both SDAP and auSDAP decreased tumor necrosis factor α, IL-6, transforming growth factor β, and soluble IL-2 receptor contents (P < 0.05). Mucosal IL-1β was decreased in SDAP compared with auSDAP and control groups (P < 0.05). The SDAP and control groups had increased mucosal IL-2 compared with auSDAP group (P < 0.05). The cytokines in serum were not affected by SDAP and auSDAP. The results indicate that both SDAP and auSDAP improved the growth performance of neonatal piglets, whereas the SDAP had a greater effect. The benefits of SDAP probably resulted from the promotion of the intestinal development, which were accompanied by the increased antioxidant capacity and the decreased production of inflammatory factors in the intestinal mucosa.

[Catalase activity in lung, kidney and small bowel non-ischemic in rats after intestinal reperfusion]

OBJECTIVE

This study aimed to assess the catalase activity after ischemia and reperfusion and to study the changes of this antioxidant in organs located far from the initial insult.

METHODS

Eighteen Wistar rats were randomly divided into three groups. 1-Control, 2-Simulation and 3-Ischemia and Reperfusion. In the latter it was done an ischemia of the ileum for 60 minutes followed by reperfusion for 30 minutes. In group 2 only laparotomy was performed. From all animals it was taken segments of the reperfused and non reperfused intestine, as well of the right kidney and lung to be evaluated under light microscopy. Catalase activity was measured in spectrophotometer with a wavelength set to 240 nm. It was used Mann Whitney and Kruskal Wallis statistical tests.

RESULTS

There was a significant increase (p <0.05) in the catalase activity not only at small bowel ischemic and non-ischemic segments but also at lungs. However the enzymatic activity decreases in the kidney. In all organs studied at reperfusion group it was found a slight villi derangement, mild congestion and infiltration with inflammatory cells, and areas of pulmonary atelectasis.

CONCLUSION

The intestinal oxidative stress in rats causes biochemical changes at distance, with mobilization of antioxidant defense mechanisms in lung, non-ischemic intestinal segment and kidney, with early decrease in this last organ, however, with no relevant cellular damage.

Ethanol-induced changes in lipid peroxidation of enterocytes across the crypt-villus axis in rats

BACKGROUND

Reactive oxygen species (ROS) have been implicated in the turnover of epithelial cells in the rat intestine. The metabolism of ethanol generates ROS, which are implicated in cellular injury, but the levels of lipid peroxidation in intestine in chronic alcoholism are unknown.

AIM

To investigate the effects of ethanol ingestion on lipid peroxidation, and anti- and pro-oxidant enzyme systems in enterocytes across the crypt-villus axis in intestine.

METHODS

Wistar rats (90-100 g) were administered 1 mL of 30% ethanol daily for 39 days. Intestinal epithelial cells were isolated in fractions. Malondialdehyde levels, and activities of glutathione-S-transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD) and catalase were determined in various cell fractions. Incorporation of H3-thymidine into DNA of enterocytes was also determined.

RESULTS

Lipid peroxidation was elevated by two- to three-folds in both villus and crypt cells in ethanol-fed animals compared to controls. The activities of GST and GR were four- to six-folds higher in villus tip cells compared to crypt base cells. The activities of SOD and catalase were five- to seven-fold higher in crypt base cells compared to villus tip cells. Ethanol feeding elevated the activities of SOD (76-190%) and catalase (20-150%) in enterocytes all along the crypt-villus axis compared to the controls. H3 thymidine incorporation into DNA of enterocytes was reduced by half in ethanol-fed rats compared to controls.

CONCLUSIONS

There is a gradient in the concentration of lipid peroxides in enterocytes across the crypt-villus axis, being high at the villus tip and low at the crypt base in the rat intestine. Ethanol feeding enhanced lipid peroxidation in both villus and crypt cells.

Dietary Fat Feeding Alters Lipid Peroxidation in Surfactant-like Particles Secreted by Rat Small Intestine

Background

Long-term feeding of fish oil (n-3) and corn oil (n-6) markedly enhances levels of lipid peroxidation within isolated rat enterocytes. The effect is 10-fold greater at the villus tip than in the crypt region, correlating with the distribution of deleterious oxidative systems (glutathione reductase) in the tip and beneficial systems (superoxide dismutase) at the base of the villus. Because of this vertical gradient of peroxidation, the process was thought to play a role in apoptosis of enterocytes at the villus tip. Surfactant-like particles (SLPs) are membranes secreted by the enterocyte and a component of these membranes is directed to the intestinal surface overlying villus tips. One suggested role for SLPs has been to protect the mucosal surface from the harsh luminal conditions that might enhance apoptotic loss of enterocytes. The hypothesis to be tested was whether SLP lipids, like those in enterocytes, were also peroxidized, although they were external to the cellular processes that seem to oxidize enterocyte lipids, or whether SLP were immune to these biological processes. Feeding with groundnut oil (n-9) was compared with fish oil (n-3) and corn oil (predominantly n-6) to determine whether oils with various lipid composition would affect peroxidation in both SLP and enterocytes.

Methods

After an overnight fast, Wistar rats were fed 2 mL of dietary oil by gavage. Five hours later SLPs and underlying microvillus membranes (MVM) were isolated and analyzed for generation of thiobarbituric acid reactive substances (TBARS) and for hydrolase activities, at baseline and after addition of an Fe⁺²/ascorbate system to induce peroxidation.

Results

In vitro lipid peroxidation using the Fe²⁺/ascorbate system produced greater peroxidation than in MVM. Intestinal alkaline phosphatase (IAP), sucrase and lactase activities were decreased in SLPs, but were unaltered in MVM except for IAP. The activities of maltase, trehalase, Leucine aminopeptidase and γ–glutamyltranspeptidase, were unaffected both in SLPs and MVM under these conditions.

Conclusions

SLPs are more susceptible to oxidative damage than are the underlying MVMs. This may reflect results of a hostile luminal environment. It is not clear whether SLPs are acting as a lipid ‘sink’ to protect the MVM from greater oxidation, or are providing an initial stimulus for apoptosis of villus tip enterocytes, or both.