Intestinal GSH Research Articles

The kinetics of glutathione in the gastrointestinal tract of weaned piglets supplemented with different doses of dietary reduced glutathione.

This study aimed to investigate the kinetics of dietary GSH in the gastrointestinal tract and the effect of GSH on the intestinal redox status of weaned piglets. Forty-eight piglets with an average age of 26 days and an average body weight of 7.7 kg were used in this study. The piglets were divided into three treatment groups including the control group with a basal diet (CON) and two GSH groups with a basal diet supplemented with 0.1% GSH (LGSH) and 1.0% GSH (HGSH), respectively. The basal diet did not contain any GSH. The experiment lasted for 14 days, with eight animals sampled from each group on d5 and 14. The parts of 0-5%, 5-75%, and 75-100% of the length of the small intestine were assigned to SI1, SI2, and SI3. The results showed that GSH almost completely disappeared from the digesta at SI2. However, no difference in the GSH level in mucosa, liver, and blood erythrocytes was found. The level of cysteine (CYS) in SI1 digesta was significantly higher in HGSH than CON and LGSH on d14, and similar findings were observed for cystine (CYSS) in SI3 digesta on d5. The CYSS level in HGSH was also significantly higher than LGSH in the stomach on d14, while no CYS or CYSS was detected in the stomach for control animals, indicating the breakdown of GSH to CYS already occurred in the stomach. Irrespective of the dietary treatment, the CYS level on d14 and the CYSS level on d5 and 14 were increased when moving more distally into the gastrointestinal tract. Furthermore, the mucosal CYS level was significantly increased at SI1 in the LGSH and HGSH group compared with CON on d5. Glutathione disulfide (GSSG) was recovered in the diets and digesta from the LGSH and HGSH group, which could demonstrate the auto-oxidation of GSH. It is, therefore, concluded that GSH supplementation could not increase the small intestinal mucosal GSH level of weaned piglets, and this could potentially relate to the kinetics of GSH in the digestive tract, where GSH seemed to be prone to the breakdown to CYS and CYSS and the auto-oxidation to GSSG.

Comparative effects of dietary methionine and cysteine supplementation on redox status and intestinal integrity in immunologically challenged-weaned pigs.

Sulfur-containing amino acids such as methionine and cysteine play critical roles in immune system and redox status. A body of evidence shows that metabolic aspects of supplemented Met and Cys may differ in the body. Therefore, the study aimed to investigate the effects of dietary Met and Cys supplementation in immunologically challenged weaned pigs. Forty weaned piglets (6.5 ± 0.3kg) were randomly allocated to five treatment groups. The treatment included: (1) sham-challenged control (SCC), (2) challenged control (CC), (3) MET (CC + 0.1% DL-Met), (4) CYS (CC + 0.1% L-Cys), and (5) MET + CYS (CC + 0.1% DL-Met + 0.1% L-Cys). On day 7, all pigs were intramuscularly injected with either Escherichia coli O55:B5 lipopolysaccharides (LPS) or phosphate-buffered saline. Blood, liver, and jejunum samples were analyzed for immune response and redox status. The CC group had lower (P < 0.05) villus surface area and higher (P < 0.05) flux of 4-kDa fluorescein isothiocyanate dextran (FD4) than the SCC group. A lower (P < 0.05) glutathione (GSH) concentration was observed in the jejunum of pigs in the CC group than those in the SCC group. Dietary Cys supplementation increased (P < 0.05) villus surface area, GSH levels, and reduced (P < 0.05) the flux of FD4 in the jejunum of LPS-challenged pigs. Dietary Met supplementation enhanced (P < 0.05) hepatic GSH content. Pigs challenged with LPS in the MET group had lower serum IL-8 concentration than those in the CC group. There was a Met × Cys interaction (P < 0.05) in serum IL-4 and IL-8 concentrations, and Trolox equivalent antioxidant capacity. Dietary L-Cys supplementation restored intestinal integrity and GSH levels that were damaged by lipopolysaccharides administration. Dietary DL-Met supplementation improved hepatic GSH and reduced systemic inflammatory response, but antagonistic interaction with dietary L-Cys supplementation was observed in the inflammatory response and redox status.

Protective effect of a new generation of activated and purified bentonite in combination with yeast and phytogenic substances on mycotoxin challenge in pigs.

The study aimed to investigate the efficacy of new mycotoxin adsorbents based on purified and activated bentonites combined with yeast and phytogenic compounds in fattening pigs. The experiment involved 96 pigs (31.2±2.4 kg). Control (C) group was fed a diet naturally contaminated with mycotoxins (5 mg/kg deoxynivalenol, DON) without an adsorbent. Treated groups received the feed with mycotoxin adsorbents: purified and activated bentonite (T1), purified and activated bentonite, yeast derivatives, phytogenic substances (T2), and purified, activated, and sulphurated bentonite with phytogenic substances (T3). Evaluated parameters involved growth performance, organ weight, small intestine and liver histopathology, complete blood count, serum biochemistry, antioxidant status of the organism and total and free DON content in urine. In all treated groups, an significant increase in intestinal GSH and GSH/GSSG ratio was observed when compared to C. No significant effects on liver and kidney weight, complete blood count, serum or intestinal malondialdehyde concentration, or total/free DON content in urine were observed. All adsorbents improved histopathological findings in the liver when compared to C. Moreover, T1, and T2 groups showed no presence of inflammatory reaction or necrotic changes in the livers. Although, mycotoxin adsorbents investigated in this study had no significant impact on pig growth performance, they reduced the oxidative stress, and on the tissue level they protected the jejunal tissue and liver parenchyma under deoxynivalenol challenge.

217 Comparative Effects of Dietary Methionine and Cysteine Supplementation on Redox Status and Intestinal Integrity in Immunologically Challenged-weaned Pigs

Abstract The aim was to investigate the effects of dietary Met and Cys supplementation in immunologically challenged-weaned pigs. Forty weaned piglets (6.51 ± 0.29 kg) were randomly allocated to five treatments and fed the assigned diets for 9 days. The treatments included: (1) sham-challenged control (SCC), (2) challenged control (CC), (3) MET (CC + 0.1% DL-Met supplementation), (4) CYS (CC + 0.1% L-Cys supplementation), and (5) MET+CYS (CC + 0.1% DL-Met and 0.1% L-Cys supplementation). Piglets were intramuscularly injected with either lipopolysaccharides (LPS; 30 μg/kg) or saline solution on day 7. All data were analyzed using single degree of freedom contrasts in the mixed procedure of SAS to test the effect of LPS challenge, Met supplementation, Cys supplementation, and Met × Cys supplementation. The CC group had lower (P &amp;lt; 0.05) villi height and villi surface area and glutathione (GSH) concentration and higher (P &amp;lt; 0.05) flux of 4-kDa fluorescein isothiocyanate dextran (FD4) in the jejunum than SCC group. Dietary Cys supplementation increased (P &amp;lt; 0.05) villi surface area, GSH concentration and reduced GSH: oxidized GSH and decreased (P &amp;lt; 0.05) the flux of FD4 in the jejunum. Dietary Met supplementation enhanced (P &amp;lt; 0.05) hepatic GSH content. Pigs in the MET group had greater mRNA abundance of IL-6 and IL-10 (P &amp;lt; 0.05) and lower serum IL-8 concentration than those in the CC group. There were Met × Cys interactions (P &amp;lt; 0.05) in serum IL-4 and IL-8 concentrations and hepatic Trolox equivalent antioxidant capacity. In conclusion, dietary L-Cys supplementation restored intestinal integrity and GSH concentration that were affected by LPS challenge. Dietary DL-Met supplementation improved hepatic GSH and reduced systemic inflammatory response, but antagonistic interaction with dietary Cys supplementation was observed in inflammatory response and redox status.

Modified Liumo decoction and polyethylene glycol 4000 powder in the treatment of functional constipation with Qi stagnation type

Objective To evaluate the efficacy of modified Liumo decoction combined with polyethylene glycol 4000 powder in the treatment of functional constipation (FC) with Qi stagnation type. Methods A total of 92 FC patients who met the inclusion criteria were divided into two groups by random number table method, 46 in each group. The control group was treated with polyethylene glycol 4000 powder orally on the basis of routine treatment. The treatment group was treated with modified Liumo decoction on the basis of the control group. Both groups were treated for 4 weeks and followed up for 6 months. TCM syndrome was scored before and after treatment. The Serum levels of NOS, NO, SOD, MDA and glutathione (GSH) were detected by ELISA. The adverse reaction during treatment was observed and the recurrence rate was calculated. Results After treatment, the score of defecation discomfort, abdominal distention, bowel ringing, sagittal frequency and chest and rib fullness in the treatment group was significantly lower than those in the control group (t=-4.749, -5.140, -5.835, -6.883, -6.919, all Ps<0.01). The level of serum NOS (26.95 ± 5.11 U/ml vs. 31.36 ± 7.61 U/ml, t=-3.263), NO (61.91 ± 12.62 U/ml vs. 72.35 ± 12.03 U/ml, t=-4.061) in the treatment group was significantly lower than those in the control group (P<0.01), the level of serum SOD (24.66 ± 3.82 U/ml vs. 21.39 ± 3.41 U/ml, t=4.331), GSH (12.15 ± 1.52 U/ml vs. 8.13 ± 1.42 U/ml, t=-13.278) in the treatment group was significantly higher than those of the control group (P<0.01), while the MAD level (2.73 ± 0.83 U/ml vs. 4.92 ± 0.75 U/ml, t=13.108) in the treatment group was significantly lower than that in the control group (P<0.01). After 6 months of follow-up, the recurrence rate of the control group was 27.3% (9/33), which was significantly higher than 4.8% (2/42) of the treatment group , and the difference was statistically significant (χ2=7.482, P=0.006). Conclusions The modified Liumo decoction combined with polyethylene glycol 4000 powder can improve the levels of intestinal neurotransmitters, SOD, MDA and GSH in patients with FC, alleviate the symptoms of traditional Chinese medicine and reduce the recurrence rate. Key words: Constipation; Functional; Qi stagnation syndrome; Neurotransmitter drugs (TCD); Modified Liumo decoction; Polyethylene glycol 4000 powder

Timing of developmental reduction in epithelial glutathione redox potential is associated with increased epithelial proliferation in the immature murine intestine.

BackgroundThe intracellular redox potential of the glutathione (GSH)/glutathione disulfide (GSSG) couple regulates cellular processes. In vitro studies indicate that a reduced GSH/GSSG redox potential favors proliferation, while a more oxidized redox potential favors differentiation. Intestinal growth depends upon an appropriate balance between the two. However, how the ontogeny of intestinal epithelial cellular (IEC) GSH/GSSG redox regulates these processes in the developing intestine has not been fully characterized in vivo.MethodsOntogeny of intestinal GSH redox potential and growth were measured in neonatal mice.ResultsWe show that IEC GSH/GSSG redox potential becomes increasingly reduced (primarily driven by increased GSH concentration) over the first 3 weeks of life. Increased intracellular GSH has been shown to drive proliferation through increased poly-ADP-ribose polymerase (PARP) activity. We show that increasing IEC poly-ADP-ribose chains can be measured over the first 3 weeks of life indicating an increase in IEC PARP activity. These changes are accompanied by increased intestinal growth and IEC proliferation as assessed by villus height/crypt depth, intestinal length, and Ki67 staining.ConclusionUnderstanding how IEC GSH/GSSG redox potential is developmentally regulated may provide insight into how premature human intestinal redox states can be manipulated to optimize intestinal growth and adaptation.

Comparison of the protective effect of self-emulsifying peptide drug delivery systems towards intestinal proteases and glutathione

AimThe aim of this study was to evaluate the protective effect of self-emulsifying drug delivery systems (SEDDS) for therapeutic peptides towards intestinal proteases and reduced glutathione (GSH). MethodsSodium docusate was applied as anionic surfactant for hydrophobic ion pairing with leuprorelin (LEU), insulin (INS) and desmopressin (DES). The complexes were loaded into SEDDS that were characterized regarding droplet size distribution and zeta potential. The release profile of the peptides was examined by dialysis membrane method. Enzymatic digestion studies were performed by applying α-chymotrypsin, trypsin and elastase. Furthermore, the protective effect of SEDDS towards degradation through thiol-disulfide exchange reactions was examined by addition of GSH. ResultsSEDDS showed a mean droplet size of 0.27–3.9μm and a zeta potential of –25 to –33mV. All formulations provided a sustained release of the peptides over 6h. Degradation of the model peptides by intestinal proteases and GSH could only be observed in the release medium. In the oily phase of SEDDS neither any of the proteases nor GSH was soluble (≤0.1%). Furthermore, no degradation of the model peptides by proteases and GSH took place in the oily phase of SEDDS. ConclusionSEDDS can provide a 100% protective effect towards protease degradation and deactivation by GSH. According to this, SEDDS might be promising tools for oral delivery of peptide drugs.

Characterization of Intestinal Ischemia/Reperfusion-Induced Decrease of Intestinal Glutathione

Intestinal ischemia followed by reperfusion has been widely studied, and oxidative stress generated by the production of reactive oxygen species is one major pathophysiological mechanism involved. The reduced form of glutathione (GSH) as part of the cellular antioxidant defense is affected during this process. The aim of this study was to perform a systematic study on the time course of intestinal GSH during intestinal ischemia, and ischemia followed by reperfusion (I/R) to clarify its role in I/R. Wistar rats were subject to laparotomy and ischemia achieved by clamping the intestinal vascular axis, and releasing the elastic band for the reperfusion period. Ischemia and I/R were monitored by surface oxygen and carbon dioxide electrodes. GSH was assayed by high pressure liquid chromatography. Our results showed thatischemia induced slight decreases in cecalGSH that could not be established as significant in the 120 min ischemia group. However, 5 and 30 min of reperfusion following different times of ischemia promoted a time-dependent decrease of GSH that reached 30% of control values. In conclusion, intestinal GSH may play a critical role during I/R in view of the correlation between its concentration after revascularization and the time of ischemia, which deserves further investigation.

시스플라틴으로 유발된 랫트의 위장관 운동장애에 대한 태음조위탕의 효과

Objectives This study aimed to observe the effect of Taeumjowi-tang on the cisplatin-induced gastrointestinal dysfunctions in rats. Methods Four groups, each of 8 rats per group, were used in this study. Saline and distilled water treated control rats were intact vehicle control group. Delayed gastrointestinal motility was induced by intraperitoneal treatment of cisplatin 2mg/kg, once a week for 5 weeks(Cisplatin control group). Taeumjowi-tang aqueous extracts(TJ) were orally administered in a volume of 5ml/kg, once a day for 14 days from 4th cisplatin treatment(TJ group). Ondansetron 1mg/kg was subcutaneously treated, in a volume of 1ml/kg, as same as TJ(ondansetron group). We measured the body weights, intestinal charcoal transit ratio, fecal parameters, fundus MDA(malondialdehyde), GSH(glutathione) contents and SOD(superoxide dismutase), CAT(catalase) activities, TPH(tryptophanhydroxylase) and MAO(monoamine oxidase) activities, pyloric gastrin and serotonin contents with their immunoreactive cells, colonic serotonin-immunoreactive cells, the histopathology of pylorus, fundus mucosa and colon. Results 1) The body weight gains, the small intestinal charcoal transfer rates, the fecal parameters(numbers, weights and water contents) were increased in TJ, ondansetron group. 2) The inhibit of fundus antioxidant defense systems by cisplatin were decreased in TJ, ondansetron group. 3) The pyloric TPH activities were increased and the pyloric MAO activities were decreased in TJ group. 4) The pyloric gastric contents and the gastrin-immunoreactive cells were increased and the pyloric serotonin contents and the pyloric and colonic serotonin-immunoreactive cells were decreased in TJ group. 5) The pylorus atrophic changes and the gastric surface erosive damage regions by cisplatin were favorably inhibited by treatment of TJ group. Conclusions The results obtained in this study suggest that TJ favorably retarded the cisplatin related GI(gastrointestinal) dysfunctions and constipation through modulations of GI enterochromaffin cells, serotonin and gastrin-producing cells and antioxidative systems.

향사양위탕이 시스플라틴 유발 랫트의 위장관 기능 장애에 미치는 영향

Beneficial Effect of Hyangsayangwi-tang on the Cisplatin-Induced Gastrointestinal Dysfunctions in Rats Eun-Hee Seo, Seong-Tae Kim, Na-Young Bae, Ae-Ryun Choi Dept. of Sasang Constitutional Medicine, College of Oriental Medicine, Daegu Haany Univ. Dept. of Sasang Constitutional Medicine, Div. of clinical medicine, School of Korean Medicine, Pusan National University Objectives This study aimed to observe the effect of Hyangsayangwi-tang on the cisplatin-induced gastrointestinal dysfunctions in rats. Methods Four groups(each of 8 rats per group) were used in this study. Saline and distilled water treated control rats are Intact vehicle control group. Delayed gatrointestinal mortility was induced by intraperitoneal treatment of cisplatin 2mg/kg, once a week for 5 weeks(Cisplatin control group). Hyangsayangwi-tang aqueous extracts(HY) were orally administered in a volume of 5ml/kg, once a day for 14 days from 4th ciplatin treatmernt(HY group). Ondansetron 1mg/kg was subcutaneously treated, in a volume of 1ml/kg, as same as HY(ondansetron group). We measured the body weights, intestinal charcoal transit ratio, fecal parameters, fundus MDA, GSH contents and SOD, CAT activities, TPH and MAO activities, pyloric gastrin and serotonin contents with their immunoraective cells, colonic serotonin-immunoreactive cells, the histopathology of pylorus, fundus mucosa and colon. Results and Conclusions (1) The body weight gains, the small intestinal charcoal transfer rates, the fecal parameters(numbers, weights and water contents) were increased in HY, ondansetron group. (2) The inhibit of fundus antioxidant defense systems by cisplatin were decreased in HY, ondansetron group. (3) The pyloric TPH activities were increased and the pyloric MAO activities were decreased in HY group. (4) The pyloric gastric contents and the gastrin-immunoreactive cells were increased in HY group. And the pyloric serotonin contents and the pyloric and colonic serotonin-immunoreactive cells were decreased in HY group. (5) The pyloru atrophic changes and the gastric surface erosive damage regions by cisplatin were favorably inhibited by treatment of HY. HY, a representative Soeumin prescription improve GI dysfunctions and constipation retarded by cisplatin through modulations of GI enterochromaffin cells, serotonin and gastrin-producing cells and antioxidative systems. Especially HY showed the highest favorable effects more than those of ondansetron.

The utilization of sulfur amino acid in the mercapturate pathway to detoxify maximal therapeutic dose of acetaminophen is associated with glutathione and protein homeosteny in adult rats

It has been shown that sulfur amino acids (SAA) used for acetaminophen (APAP) detoxification, as sulfate conjugate and mercapturate (glutathione (GSH) conjugation), can represent a significant part of dietary SAA and lead to GSH and protein homeosteny. We determined the metabolic alterations induced by APAP detoxification in adult rats receiving daily the half or maximal therapeutic French dose for human. APAP was provided in a 16% protein diet at the dose of 0 (control, n=6), 0.5 (n=7) or 1% (n=7) for 17 days. 1% APAP reduced nitrogen balance (36%), weights of small intestine (13%) and gastrocnemius (7%), hepatic, muscular and intestinal GSH levels by 56%, 20% and 8%, respectively. These parameters were unchanged by 0.5% APAP. Urinary sulfate conjugate was independent of APAP dose, whereas mercapturate of APAP increased from 3% to 14% of ingested SAA in 0.5 and 1% APAP, respectively. Posttranslational alterations of hepatic proteins (APAP protein adducts and modified residues, assessed by target and global metabolomics) occurred with 0.5% APAP and to a larger extent with 1% APAP. Variations of all studied parameters occurred with the APAP dose that is accompanied by upper use of SAA. Further experiments are required to determine if cysteine supplementation could preserve the structure of hepatic proteins at moderate APAP dose, and limit all metabolic alterations occurring with the APAP dose at 1% of the diet.

Effects of quercetin and menadione on intestinal calcium absorption and the underlying mechanisms

Quercetin (QT) could be considered as a potential therapeutic agent for different diseases due to its antioxidant, anti-inflammatory, antiviral and anticancer properties. This study was designed to investigate the ability of QT to protect the chick intestine against menadione (MEN) induced injury in vivo and in vitro. Four-week old chicks (Gallus gallus) were treated i.p. with 2.5μmol of MEN/kg b.w. or with i.l. 50μM QT or both. QT protected the intestinal Ca2+ absorption against the inhibition caused by MEN, but QT alone did not modify. Glutathione (GSH) depletion provoked by MEN in chick enterocytes was abolished by QT treatment, whereas QT alone did not modify the intestinal GSH content. The enhancement of GSH peroxidase activity produced by MEN was blocked by QT treatment. In contrast, superoxide dismutase activity remained high after simultaneous treatment of enterocytes with MEN and QT. The flavonol also avoided changes in the mitochondrial membrane permeability (swelling) produced by MEN. The FasL/Fas/caspase-3 pathway was activated by MEN, effect that was abrogated by QT. In conclusion, QT may be useful in preventing inhibition of chick intestinal Ca2+ absorption caused by MEN or other substances that deplete GSH, by blocking the oxidative stress and the FasL/Fas/caspase-3 pathway activation.

Evidence for intestinal oxidative stress in patients with obstructive jaundice

Obstructive jaundice results in failure of the intestinal barrier with consequent systemic endotoxemia associated with septic complications. We have recently shown that gut barrier failure in experimental obstructive jaundice is associated with high intestinal oxidative stress. This study was undertaken to investigate whether oxidative alterations occur in the intestinal mucosa of patients with obstructive jaundice. Fifteen patients with malignant biliary obstruction and no signs of cholangitis and 15 control patients were subjected to duodenal biopsy to assess intestinal oxidative stress, estimated by lipid peroxidation (malondialdehyde - MDA) and glutathione redox state [reduced glutathione (GSH), glutathione disulphide (GSSG) and GSH/GSSG ratio]. In addition, mucosal biopsies were examined histologically and intestinal mucosal protein content was determined biochemically as an index of intestinal trophic state. Patients with obstructive jaundice presented high levels of intestinal oxidative stress, with significantly increased lipid peroxidation (P < 0.001). Glutathione redox state was also suggestive of high intestinal oxidative stress in jaundiced patients, indicated by significantly decreased GSH (P = 0.001) and GSH/GSSG ratio (P = 0.006) and increased GSSG (P = 0.026). Histological examination showed a mild infiltration of the lamina propria by chronic inflammatory cells in obstructive jaundice, whereas duodenal architecture remained intact and epithelial continuity was retained. Duodenal mucosa was atrophic in jaundiced patients as indicated by a significant reduction of mucosal protein content compared with controls (P = 0.001). Among oxidative stress parameters, intestinal GSH exhibited a significant positive correlation with mucosal protein content (r = 0.588, P = 0.021). Obstructive jaundice in humans induces intestinal oxidative stress, which may be a key factor contributing to intestinal barrier failure and the development of septic complications in this patient population.

Aluminium-induced impairment of transcellular calcium absorption in the small intestine: Calcium uptake and glutathione influence

Aluminium (Al) has been recognised as a cause of bone tissue disorders. The aims of this work were to investigate: (i) whether Al affects calcium (Ca) entry into enterocyte, and (ii) the possibility that the Al effect upon calbindin-D-related Ca transport would be influenced by intestinal glutathione (GSH) levels. In isolated chicken duodenal enterocytes, 100 μM Al lactate produced a decrease in both, the maximum uptake rate and the affinity constant of 45Ca uptake (CaUPT). This effect of Al on CaUPT was concentration-dependent in the micromolar range, showing an inhibitory saturation type phenomenon which appeared to be higher at pH 6.5 than at pH 7.4, and was not modified by the Ca channel activators A23187 and capsaicin. The simultaneous administration of Al (50 mg elemental Al/kg body weight, as AlCl 3) and GSH (10 mmol/kg body weight) to rats during 7 days, prevented the inhibitory effects of Al on Ca transport. The protective effect of GSH was accompanied by an increased duodenal calbindin-D 9k expression. Experimental depletion of intestinal GSH by means of d,l-buthionin-[S,R] sulfoximine, a γ-glutamylcystein-synthase inhibitor, given as a single i.p. dose of 2 mmol/kg body weight, enhanced the degree of reduction of Ca absorption ascribed to Al. Our results suggest that Al might interfere Ca uptake by enterocytes through a general effect on cell membrane, and that an oxidative stress state induced by Al would reduce intestine GSH level affecting calbindin-D function and/or synthesis, thus leading to a reduced transcellular Ca absorption in the small intestine.

The healing-promoting effect of saliva on skin burn is mediated by epidermal growth factor (EGF): role of the neutrophils

Local skin trauma induces inflammatory responses resulting in local tissue and distant organ injury. EGF, a polypeptide hormone, mainly produced in saliva, is one of the major accelerators in wound healing. Wistar albino rats of both sexes received either bovine serum albumin or EGF (10 μg/kg) subcutaneously before a circular (18 mm diameter) partial thickness burn was induced. Afterwards, some rats were placed in separate cages to prevent licking, while the others were caged together to allow wound-licking. Treatments were continued for 5 more days and on the 5th day animals were decapitated. Histopathological analysis of skin damage and dermal myeloperoxidase (MPO) activity, as an index for neutrophil activity, were evaluated. Oxidant injury to the liver and intestines was determined by measuring glutathione (GSH) and malondialdehyde (MDA) levels, as well as MPO activity. The results demonstrate that healing of the burn wound on the skin is accelerated by both wound-licking and EGF administration, which also attenuated tissue neutrophil accumulation, suggesting the role of neutrophils as the source of mediators involved in delayed epithelial regeneration. Moreover, local dermal burn results in oxidant injury to the liver, concomitant with significant elevations in hepatic and intestinal GSH levels. Exogenous administration of EGF at physiological doses had no effect on inflammatory responses of the distant organs, while allowing the rats to lick the wound reduced the oxidant injury to the liver. Since saliva or EGF enhances skin wound healing, topical use of EGF-rich artificial saliva merits consideration for its use in burn patients.

Hibernation induces glutathione redox imbalance in ground squirrel intestine.

Glutathione (GSH) is the major thiol-disulfide redox buffer in cells and is a critical component of antioxidant defense. Here we examined GSH redox balance in the intestinal mucosa during the annual cycle of 13-lined ground squirrels (Spermophilus tridecemlineatus). The ratio of reduced GSH to its oxidized form (glutathione disulfide, GSSG), which is an index of oxidative stress, was five-fold lower in hibernating compared with summer-active squirrels, an effect due primarily to elevated GSSG concentration in hibernators. During hibernation the total pool of GSH equivalents was lowest in squirrels undergoing arousal and highest in squirrels during interbout arousals. Hibernation decreased intestinal GSSG reductase activity by approximately 50%, but had no effect on activities of glutathione peroxidase or glucose-6-phosphate dehydrogenase. Within the hibernation season, expression of the stress protein HSP70 in intestinal mucosa was highest in squirrels entering torpor and early in a torpor bout, and lowest in squirrels arousing from torpor and during interbout euthermia. The results suggest that hibernation in ground squirrels is associated with a shift in intestinal GSH redox balance to a more oxidized state. Higher levels of HSP70 during the early phases of torpor may reflect induction of the stress response due to aberrations in protein folding or may be a mechanism to increase enterocyte tolerance to subsequent stress imposed by extended torpor or the arousal process.

Chronic exposure to subtoxic levels of peroxidized lipids suppresses mucosal cell turnover in rat small intestine and reversal by glutathione.

Oxidative challenge can compromise intestinal growth and death responses. This studyexamines the effect of chronic consumption of subtoxic levels of peroxidized lipids on intestinal redox balance and turnover and the effect of glutathione (GSH) supplementation. Male Sprague-Dawley rats were fed standard rat chow or 4% peroxidized menhaden oil chow (2-8 weeks). Intestinal GSH and glutathione disulfide (GSSG), GSH synthetic and redox enzymes as well as proliferative (ornithine decarboxylase, ODC) and apoptotic activities were evaluated. Chronic peroxide intake did not affect overall animal growth, but decreased intestinal GSH/GSSG ratio that directly correlated with decreased GSH and increased GSSG, and suppressed peak circadian ODC activities and post-prandial mucosal apoptosis. Supplementation with GSH restored the mucosal GSH/GSSG ratio and abrogated the peroxide-induced suppression of intestinal cell turnover. Collectively, the results show that chronic lipid peroxide consumption induces intestinal GSH redox imbalance that interferes with regulation of enterocyte death and proliferation in vivo. These disruptive effects of lipid peroxides were reversed by GSH supplementation in accordance with the normalization of tissue GSH/GSSG redox balance.

Keratinocyte Growth Factor Enhances Glutathione Redox State in Rat Intestinal Mucosa during Nutritional Repletion

Malnutrition decreases tissue levels of glutathione (GSH), a major endogenous antioxidant that detoxifies reactive oxygen species and promotes cell growth. This study determined the effects of the gut trophic peptide keratinocyte growth factor (KGF) on intestinal mucosal GSH concentrations and redox state in malnourished rats. Adult rats were food-deprived for 3 d, then consumed food ad libitum or 25% of ad libitum intake for 3 d with daily intraperitoneal administration of saline or KGF (5 mg⋅kg-1⋅d-1). Mucosal GSH and glutathione disulfide (GSSG) concentrations, crypt depth and total mucosal height were measured in the jejunum, ileum and colon. In the 25% of ad libitum-refed, saline-treated group, mucosal GSH was lower in all gut tissues (42% in jejunum, 38% in ileum, and 57% in colon), and the GSH/GSSG ratio was lower in the jejunum and ileum compared to that in the ad libitum-refed controls. KGF treatment with ad libitum refeeding increased GSH/GSSG in the jejunum, ileum and colon. Furthermore, in 25% of ad libitum refeeding, KGF normalized jejunal, ileal and colonic mucosal GSH content and significantly increased the mucosal GSH/GSSG ratio relative to rats treated with saline. Increased crypt depth and total mucosal height induced by KGF and feeding could be explained in part by increased mucosal GSH content. KGF treatment improved gut mucosal glutathione redox state in malnourished, refed rats. These data provide evidence that gut trophic hormones and food intake may independently support gut mucosal glutathione antioxidant capacity during nutritional repletion.

Impairment of intestinal glutathione synthesis in patients with inflammatory bowel disease

Background—Reactive oxygen species contribute to tissue injury in inflammatory bowel disease (IBD). The tripeptide glutathione (GSH) is the most important intracellular antioxidant.Aims—To investigate constituent amino acid plasma levels and the...

Effects of the sulforaphane analog compound 30, indole-3-carbinol, d-limonene or relafen on glutathione S-transferases and glutathione peroxidase of the rat digestive tract

Several dietary compounds have been demonstrated to reduce gastrointestinal cancer rates in both humans and animals. We showed that high human gastrointestinal tissue levels of glutathione S-transferase (GST), a family of detoxification enzymes consisting of class Alpha, Mu, Pi and Theta isoforms, were inversely correlated with cancer risk. We now investigated whether the sulforaphane analog compound 30, indole-3-carbinol, d-limonene or relafen, supplemented in the diet for two weeks at 1450, 250, 10 000, and 200 ppm, respectively, influenced (i) GST activity, (ii) GST isoenzyme levels, (iii) GSH levels, or (iv) glutathione peroxidase (GPx) activity in the gastrointestinal tract of male Wistar rats. Sulforaphane analog compound 30 enhanced GST activity in all organs studied (1.2–2.4×). It induced GST Alpha levels in small intestine and liver, GST Mu levels in stomach and small intestine, GST Pi levels in stomach and small and large intestine, and GSH levels in stomach and proximal and middle small intestine. Indole-3-carbinol induced gastric GST Mu and hepatic GST Alpha levels. d-limonene induced hepatic GST Alpha, colonic GST Pi levels and proximal small intestinal GST enzyme activity and GST Pi levels. Relafen induced hepatic GST Alpha levels, distal small intestinal and gastric GST Pi levels, and oesophageal and proximal small intestinal GSH levels. GPx activity was enhanced by relafen in oesophagus, and in distal small intestine by sulforaphane analog compound 30. Enhancement of GSTs and to a lesser extent GPx and GSH, resulting in a more efficient detoxification, may explain at least in part the anticarcinogenic properties of sulforaphane analog compound 30, and to a much lesser extent of indole-3-carbinol and d-limonene.