Partial sleep deprivation compromises gastric mucosal integrity in rats

Dendrobium huoshanense stem polysaccharide ameliorates alcohol-induced gastric ulcer in rats through Nrf2-mediated strengthening of gastric mucosal barrier

This study aimed to explore whether Dendrobium huoshanense stem polysaccharide (cDHPS) ameliorates alcohol-induced gastric ulcer (GU) through the strengthening effect of the gastric mucosal barrier in rats and its potential mechanism. In normal rats, the pretreatment of cDHPS effectively strengthened gastric mucosal barrier by increasing mucus secretion and tight junction protein expression. In GU rats, cDHPS supplementation effectively alleviated alcohol-induced gastric mucosal injury and nuclear factor κB (NF-κB)-driven inflammation by strengthening gastric mucosal barrier. Moreover, cDHPS significantly activated nuclear factor E2-related factor 2 (Nrf2) signaling and promoted antioxidant enzymes activities in both normal and GU rats. These results suggested that the pretreatment of cDHPS could strengthen gastric mucosal barrier to inhibit oxidative stress and NF-κB-driven inflammation induced gastric mucosal injury, which was likely related to the activation of Nrf2 signaling.

The role of peripheral serotonin and norepinephrine in the gastroprotective effect against stress of duloxetine

Duloxetine has been shown to produce gastroprotective effect against gastric ulcer induced by water immersion restraint stress (WIRS) via modulation of NADPH oxidases in the gastric mucosa and neurometabolites of central nucleus of amygdala. However, the underlying mechanism based on the basic pharmacological function of duloxetine-regulation on serotonin (5-HT) and norepinephrine (NE) remains unclear. Here, we found that 5-HT level in platelet-poor plasma (PPP) was decreased but NE level in plasma was increased in rats exposed to WIRS, while pretreatment with duloxetine increased 5-HT in PPP dose-dependently and decreased NE in plasma of rats after WIRS. We further showed that depletion of 5-HT by 4-chloro-DL-phenylalanine (PCPA) aggravated gastric mucosa damage and supplement of 5-HT alleviated gastric ulcers induced by WIRS. Blockade of NE receptors also mitigated the stress gastric ulcers. Using adrenalectomy and chemical blocking, we identified that it was NE from adrenal medulla rather than sympathetic nerve that was more critical in the gastroprotection of duloxetine, and intriguingly, glucocorticoid did not make a difference in WIRS-provoked gastric ulcers as a classic stress hormone. Together, our work demonstrated prophylactic protection of duloxetine from the stress gastric ulcer depended on enhancing peripheral 5-HT content and reducing NE from adrenal medulla, which provided insight into treatments of WIRS-induced gastric ulcer.

Butyrate Ameliorates Insufficient Sleep-Induced Intestinal Mucosal Damage in Humans and Mice

Insufficient sleep is a key factor in the occurrence of intestinal diseases. This study was performed to clarify how sleep deficiency mediates the intestinal microbiota, metabolite butyrate disturbance induces intestinal mucosal damage, and butyrate ameliorates it. A questionnaire was launched for sleep and intestinal health issues. Twenty-two healthy volunteers were interviewed, and the influence of insufficient sleep on the gut microbiota and metabolite composition was explored. Moreover, a 72-h sleep deprivation (SD) mouse model with or without butyrate supplementation was used to reveal the effect of butyrate on ameliorating small intestines damage caused by SD. The questionnaire survey of 534 college students showed that among 85.39% of the students who slept less than 7 h, 41.76% were suffering from various bowel disorders. High-throughput 16S rRNA pyrosequencing demonstrated that SD and sleep restriction (SR) resulted in downregulation of Faecalibacterium and butyrate abundance in the feces of college students. Furthermore, we observed that butyrate supplementation markedly reversed sleep-deprivation-induced small intestinal mucosal injury in mice. Meanwhile, butyrate supplementation inverted the SD-caused inflammation response and oxidative stress and the decline of phospho-glycogen synthase kinase 3β (p-GSK-3β), β-catenin, Nrf2, and cyclin D1 and the increase in histone deacetylase 3 (HDAC3) and phospho-P65 (p-P65) proteins in the small intestines. Furthermore, in vitro, the ameliorative effects of butyrate were blocked by treatment with the HDAC3 agonist ITSA-1 and the Nrf2 antagonist ML385 and mimicked by treatment with the HDAC3 antagonist RGFP966 and p-P65 antagonist PDTC. Our study revealed that SD and SR downregulated butyrate production, further causing intestinal homeostasis dysfunction via the HDAC3-p-GSK-3β-β-catenin-Nrf2-NF-κB pathway. IMPORTANCE Radical inflammatory bowel disease (IBD) induced by sleep deficiency is a serious global public health threat. Butyrate, a member of the short-chain fatty acids, exerts multiple effects on it. However, existing research focuses on injury to the colon caused by insufficient sleep, while the changes in the small intestines are often overlooked. This study focused on revealing the influence of insufficient sleep on the intestinal microbiota and its metabolites and further revealed the ameliorative effect of butyrate on sleep deprivation (SD)-induced small intestinal mucosal damage in human and mice. Our studies suggest that butyrate can be used as a probiotic to restore SD-induced IBD and contribute to a better understanding of the mechanisms that govern the beneficial effects of butyrate.

Poria cocos water-soluble polysaccharide modulates anxiety-like behavior induced by sleep deprivation by regulating the gut dysbiosis, metabolic disorders and TNF-α/NF-κB signaling pathway

Poria cocos (P. cocos) has been traditionally used as folk medicine and functional food in China for more than 2000 years. The water-soluble polysaccharide is the main component of P. cocos decoction. The effects and mechanisms of the water-soluble polysaccharide from P. cocos (PCWP) were investigated in chronic sleep deprivation (CSD)-induced anxiety in rats. CSD induced anxiety, gut dysbiosis, and inflammatory responses, and reduced neurotransmitter levels, whereas PCWP intervention ameliorated anxiety-like behaviors, increased the levels of 5-hydroxytryptamine, dopamine, norepinephrine, and γ-aminobutyric acid in the hypothalamus, regulated gastrointestinal peptide levels, reduced inflammatory factors, and inhibited the tumor necrosis factor (TNF)-α/nuclear factor (NF)-κB signaling pathway in rats with CSD. The changes in the intestinal flora composition were determined using 16S rDNA sequencing, and indicated that PCWP significantly improved species richness and diversity in the intestinal flora of rats with anxiety, and adjusted the abundance of the following dysregulated bacteria closer to that of the normal group: Rikenellaceae_RC9_gut_group, Ruminococcus, Prevotellaceae_UCG-001, Prevotellaceae_NK3B31_group, Fusicatenibacter. Metabolomics was used to analyze fecal samples to identify significantly altered metabolites in the PCWP-treated groups. Thirty-eight PCWP-related metabolites and four metabolic pathways such as sphingolipid metabolism, taurine and hypotaurine metabolism, vitamin B6 metabolism, and glycerophospholipid metabolism were explored. The results of serum metabolomics showed that 26 biomarkers were significantly changed after PCWP intervention compared with the model group. The regulatory effects of metabolic pathway enrichment on sphingolipid, phenylalanine, and taurine and hypotaurine metabolism, and validation results showed that PCWP intervention regulated the activity of enzymes involved in the above metabolic pathways. A strong correlation between intestinal bacteria and potential biomarkers was found. Our findings present new evidence supporting the potential effect of PCWP in preventing the progression of anxiety by inhibiting the TNF-α/NF-κB signaling pathway, alleviating metabolic disorders, and ameliorating the gut microflora imbalance.

Antidiabetic Effects of Pediococcus acidilactici pA1c on HFD-Induced Mice

Prediabetes (PreD), which is associated with impaired glucose tolerance and fasting blood glucose, is a potential risk factor for type 2 diabetes mellitus (T2D). Growing evidence suggests the role of the gastrointestinal microbiota in both PreD and T2D, which opens the possibility for a novel nutritional approach, based on probiotics, for improving glucose regulation and delaying disease progression of PreD to T2D. In this light, the present study aimed to assess the antidiabetic properties of Pediococcus acidilactici (pA1c) in a murine model of high-fat diet (HFD)-induced T2D. For that purpose, C57BL/6 mice were given HFD enriched with either probiotic (1 × 10¹⁰ CFU/day) or placebo for 12 weeks. We determined body weight, fasting blood glucose, glucose tolerance, HOMA-IR and HOMA-β index, C-peptide, GLP-1, leptin, and lipid profile. We also measured hepatic gene expression (G6P, PEPCK, GCK, IL-1β, and IL-6) and examined pancreatic and intestinal histology (% of GLP-1⁺ cells, % of goblet cells and villus length). We found that pA1c supplementation significantly attenuated body weight gain, mitigated glucose dysregulation by reducing fasting blood glucose levels, glucose tolerance test, leptin levels, and insulin resistance, increased C-peptide and GLP-1 levels, enhanced pancreatic function, and improved intestinal histology. These findings indicate that pA1c improved HFD-induced T2D derived insulin resistance and intestinal histology, as well as protected from body weight increase. Together, our study proposes that pA1c may be a promising new dietary management strategy to improve metabolic disorders in PreD and T2D.

Soporific Effect of Modified Suanzaoren Decoction and Its Effects on the Expression of CCK-8 and Orexin-A

Suanzaoren decoction (SZRT), a classic Chinese herbal prescription, has been used as a treatment for insomnia for more than a thousand years. However, recent studies have found no significant effects of SZRT as a treatment for insomnia caused by gastric discomfort. Herein, we studied the effects of modified Suanzaoren decoction (MSZRD) on gastrointestinal disorder-related insomnia. The main constituents of MSZRD were spinosin (2.21 mg/g) and 6-feruloylspinosin (0.78 mg/g). A pentobarbital-induced animal model of insomnia showed that MSZRD shortened sleep latency and prolonged sleep time of the male Institute of Cancer Research (ICR) mice treated for 7 days with oral MSZRD. Sprague-Dawley male rats were treated daily with oral MSZRD or placebo for 11 days and then deprived of sleep for the last 4 days to establish a model of insomnia. Of note, MSZRD-treated animals had significantly improved body weight, organ index scores, and fecal moisture relative to placebo-treated animals, as well as reduced temperature. Sleep-deprived rats exhibited more exploratory behaviors in an open-field anxiety test; however, this effect was significantly reduced in MSZRD-treated animals. We found that MSZRD treatment decreased gastric acid pH, decreased the production of gastrin, pepsin, and Orexin-A, and increased the expression of MTL and CCK-8. Importantly, serum GABA concentration was increased by treatment with MSZRD, as reflected by a decreased Glu/GABA ratio. Treated animals had increased the expression of GAD1, GABARA1, and CCKBR but decreased the expression of Orexin R1. In summary, these results suggest that MSZRD has soporific and gastroprotective effects that may be mediated by differential expression of CCK-8 and Orexin-A.

Melatonin alleviates oxidative stress in sleep deprived mice: Involvement of small intestinal mucosa injury

BACKGROUND

Previous research demonstrated that sleep deprivation (SD) resulted in intestinal homeostasis disorder in colon. The present study was further performed to clarify the role of melatonin in SD-induced small intestinal (SI) mucosal injury.

METHODS

We successfully established a multiplatform 72 h SD mouse model with or without melatonin supplementation to explore the improvement of melatonin in the destruction of SI induced by SD.

RESULTS

Melatonin supplementation suppressed an increase of corticosterone level and a decrease of melatonin level caused by SD. Meanwhile, we observed that melatonin supplementation in sleep deprived mice markedly reversed a decrease of the villi length/crypt depth (V/C) ratio and the number of goblet cells, PCNA positive cells, the expressions of MUC2 and tight junction proteins, as well as an upregulation of the expressions of autophagic proteins in the duodenum, jejunum and ileum. Furthermore, melatonin supplementation inverted the SD-induced the decline of antioxidant enzyme activities (T-AOC and CAT etc) and anti-inflammatory cytokines (IL-10 and IFN-γ) and the increase of oxidative product MDA, pro-inflammatory cytokines (IL-6 and TNF-α), p-P65 and p-IκB proteins in the SI.

CONCLUSIONS

These findings suggested that melatonin may be used as a probiotic agent to reverse SD-induced SI mucosa injury by suppressing oxidative stress and NF-κB pathway activation.

Role of melatonin in sleep deprivation-induced intestinal barrier dysfunction in mice

Intestinal diseases caused by sleep deprivation (SD) are severe public health threats worldwide. This study focuses on the effect of melatonin on intestinal mucosal injury and microbiota dysbiosis in sleep-deprived mice. Mice subjected to SD had significantly elevated norepinephrine levels and decreased melatonin content in plasma. Consistent with the decrease in melatonin levels, we observed a decrease of antioxidant ability, down-regulation of anti-inflammatory cytokines and up-regulation of pro-inflammatory cytokines in sleep-deprived mice, which resulted in colonic mucosal injury, including a reduced number of goblet cells, proliferating cell nuclear antigen-positive cells, expression of MUC2 and tight junction proteins and elevated expression of ATG5, Beclin1, p-P65 and p-IκB. High-throughput pyrosequencing of 16S rRNA demonstrated that the diversity and richness of the colonic microbiota were decreased in sleep-deprived mice, especially in probiotics, including Akkermansia, Bacteroides and Faecalibacterium. However, the pathogen Aeromonas was markedly increased. By contrast, supplementation with 20 and 40 mg/kg melatonin reversed these SD-induced changes and improved the mucosal injury and dysbiosis of the microbiota in the colon. Our results suggest that the effect of SD on intestinal barrier dysfunction might be an outcome of melatonin suppression rather than a loss of sleep per se. SD-induced intestinal barrier dysfunction involved the suppression of melatonin production and activation of the NF-κB pathway by oxidative stress.

Women Who Sleep More Have Reduced Risk of Peptic Ulcer Disease; Korean National Health and Nutrition Examination Survey (2008-2009)

Sleep is integral to life and sleep duration is important in sleep quality, physical, and psychological health. Disturbances in sleep duration have been associated with increased risk of metabolic disorders, hypertension, and overall mortality. Sleep disturbance has also been linked with various gastrointestinal disorders. However, the association between sleep and peptic ulcer disease (PUD) has not been evaluated. We investigated the association between sleep duration and PUD. Subjects were included from the fifth Korean National Health and Nutrition Examination Survey conducted from 2008-2009. Individuals with PUD were defined as those with a physician diagnosis of PUD. Daily sleep duration was established by asking participants the amount of time that they slept per day. Multiple logistic regression models were used to evaluate the association of PUD and sleep duration. This study included 14,290 participants (8,209 women). The prevalence of PUD was 5.7% and was higher in men (6.8%) than in women (4.9%). Women who slept ≥9 hours were significantly less likely to have PUD compared to women who slept 7 hours. In men, longer sleep duration (≥9 hours) had a tendency toward PUD prevention. Our results suggest that longer sleep duration may play a protective role for PUD development.

Bioinformatics analysis of transcriptional regulation of circadian genes in rat liver

Background

The circadian clock is a critical regulator of biological functions controlling behavioral, physiological and biochemical processes. Because the liver is the primary regulator of metabolites within the mammalian body and the disruption of circadian rhythms in liver is associated with severe illness, circadian regulators would play a strong role in maintaining liver function. However, the regulatory structure that governs circadian dynamics within the liver at a transcriptional level remains unknown. To explore this aspect, we analyzed hepatic transcriptional dynamics in Sprague-Dawley rats over a period of 24 hours to assess the genome-wide responses.

Results

Using an unsupervised consensus clustering method, we identified four major gene expression clusters, corresponding to central carbon and nitrogen metabolism, membrane integrity, immune function, and DNA repair, all of which have dynamics which suggest regulation in a circadian manner. With the assumption that transcription factors (TFs) that are differentially expressed and contain CLOCK:BMAL1 binding sites on their proximal promoters are likely to be clock-controlled TFs, we were able to use promoter analysis to putatively identify additional clock-controlled TFs besides PARF and RORA families. These TFs are both functionally and temporally related to the clusters they regulate. Furthermore, we also identified significant sets of clock TFs that are potentially transcriptional regulators of gene clusters.

Conclusions

All together, we were able to propose a regulatory structure for circadian regulation which represents alternative paths for circadian control of different functions within the liver. Our prediction has been affirmed by functional and temporal analyses which are able to extend for similar studies.

Effect of chronic restraint stress on human colorectal carcinoma growth in mice

Stress alters immunological and neuroendocrinological functions. An increasing number of studies indicate that chronic stress can accelerate tumor growth, but its role in colorectal carcinoma (CRC) progression is not well understood. The aim of this study is to investigate the effects of chronic restraint stress (CRS) on CRC cell growth in nude mice and the possible underlying mechanisms. In this study, we showed that CRS increased the levels of plasma catecholamines including epinephrine (E) and norepinephrine (NE), and stimulated the growth of CRC cell-derived tumors in vivo. Treatment with the adrenoceptor (AR) antagonists phentolamine (PHE, α-AR antagonist) and propranolol (PRO, β-AR antagonist) significantly inhibited the CRS-enhanced CRC cell growth in nude mice. In addition, the stress hormones E and NE remarkably enhanced CRC cell proliferation and viability in culture, as well as tumor growth in vivo. These effects were antagonized by the AR antagonists PHE and PRO, indicating that the stress hormone-induced CRC cell proliferation is AR dependent. We also observed that the β-AR antagonists atenolol (ATE, β1- AR antagonist) and ICI 118,551 (ICI, β2- AR antagonist) inhibited tumor cell proliferation and decreased the stress hormone-induced phosphorylation of extracellular signal-regulated kinases-1/2 (ERK1/2) in vitro and in vivo. The ERK1/2 inhibitor U0126 also blocked the function of the stress hormone, suggesting the involvement of ERK1/2 in the tumor-promoting effect of CRS. We conclude that CRS promotes CRC xenograft tumor growth in nude mice by stimulating CRC cell proliferation through the AR signaling-dependent activation of ERK1/2.

Effect of folic acid supplementation on oxidative gastric mucosa damage and acid secretory response in the rat

Objective:

This study investigated the antioxidative and antisecretory properties of folic acid in the rats’ stomach.

Materials and Methods:

Male Wistar rats were treated with 2 mg/kg diet of folic acid for 21 days. Gastric ulceration was induced by indomethacin, scored, and assayed to determine the concentration of total protein, mucus, malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD) in homogenized samples. Normal saline and Ranitidine treated group served as negative and positive control, respectively. Basal and stimulated acid secretion was measured by continuous perfusion method.

Result:

Indomethacin caused severe damage to the rats’ stomach with an ulcer index of 4.32 ± 0.13, increase in MDA concentration and reduction in the concentration of protein, mucus, catalase and superoxide dismutase (P < 0.001). Pre-treatment with folic acid prevented the formation of ulcers by 32%, and attenuated the inhibition of mucus by 14%, CAT, 51% and SOD, 150%. Ranitidine afforded 56% prevention in ulcer formation with 67%, 55% and 78% attenuation of the inhibition of mucus, CAT and SOD, respectively, by indomethacin. While indomethacin-induced lipid peroxidation was attenuated by 58% reduction in MDA concentration on pretreatment with folic acid, Ranitidine offered 65% reduction. Basal and stimulated acid secretions were significantly reduced in the treated when compared with control animals. Folic acid produced a 21% reduction in the basal acid output when compared with the control animals (P < 0.05), and 140% reduction in histamine-induced acid response.

Conclusion:

The results indicate the gastroprotective activity of folic acid due its antioxidative and anti-secretory properties.

An evaluation of the neuroendocrine response to sleep in pediatric burn patients

INTRODUCTION

Previous work demonstrated reduced stage 3+4 and rapid eye movement (REM) sleep following burn injury. This study evaluated the hormonal effects of drug intervention on measures of endocrine status. A secondary objective examined the relationship between hormones and sleep stage distribution.

METHODS

Forty patients 3-18 years of age with a mean percent total body surface area burn of 50.1 +/- 2.9 were randomly assigned to zolpidem or haloperidol utilizing a blinded crossover design. Polysomnography was performed 6 nights, 3/week over 2 weeks. Each week's first night of monitoring was conducted without medication, serving as a baseline. Hormonal levels (epinephrine, norepinephrine, growth hormone, melatonin, dehydroepiandrosterone [DHEA], serotonin, cortisol) were obtained at 0600 h each study day.

RESULTS

Both drugs were associated with increased DHEA levels (P < .03); no other hormones were affected by medication. Significant inverse correlation was observed between REM sleep and epinephrine (r = -.34, P = .004) and norepinephrine levels (r = -.45, P = .02). A positive relationship existed between serotonin and sleep stage 3+4 (r = 0.24, P = .01) and REM (r = 0.48, P = .01). No other significant associations were identified between hormones and sleep.

CONCLUSIONS

This work characterizes the relationship between sleep deprivation and select endocrine parameters postburn. Drug interventions utilized in this study were either ineffective or insufficient in modulating improved hormonal response. Significance of zolpidem's and haloperidol's effect on serum levels of DHEA is unclear. The inverse correlation of epinephrine with REM may suggest that hypermetabolism associated with burns is partly due to lack of REM sleep. Questions remain regarding the effects of sleep deprivation on metabolism and clinical outcome.

Expression of heat shock protein 60 in the tissues of transported piglets

In this study, we sought to determine the distribution and expression of heat shock protein 60 (Hsp60) in the tissues of transported piglets. A total of 24 Chinese Erhualian piglets with an average body weight of 20 +/- 1 kg were assessed under both 2-h transported and normal housing conditions. Results of enzymatic analysis showed that the serum creatine kinase and aspartate aminotransferase concentrations were significantly increased in the 2-h transported piglets. Acute cellular lesions characterized by granular and vacuolar degeneration of the parenchyma cells in the tested heart, liver, and kidney were also confirmed by histopathological test after 2 h transportation. These results indicate that transport stress induces tissue damage to heart, liver, and kidney. Hsp60-positive immunostaining was consistently detected in the cytoplasm of myocardial cells, hepatocytes, renal tubular epithelial cells, and epithelial cells of fundic gland. However, results of enzyme-linked immunosorbent assay indicated that Hsp60 expression was only significantly elevated in the stomach, with lower expression in the heart and a non-significant trend of increased liver and kidney expression of Hsp60. These results indicate that different tissues had different sensitivities to transport stress, possibly resulting in varying levels of cytoprotection by Hsp60 in the different tissues. The expression of Hsp60 following 2 h transportation coincided with deterioration of cardiac cytoprotection in the heart and protection in the stomach. However, the direct role of Hsp60 in cytoprotection of heart and stomach tissues needs further investigation.

Melatonin attenuates lipopolysaccharide-induced acute lung inflammation in sleep-deprived mice

Sleep disorders are great problems in modern society. Even minimal changes of sleep can affect health. Especially, patients with pulmonary diseases complain of sleep problems such as sleep disturbance and insomnia. Recent studies have shown an association between sleep deprivation (SD) and inflammation, however, the underlying mechanisms remain unclear. In the present study, we investigated whether melatonin protects against acute lung inflammation in SD. Male ICR mice were deprived sleep using modified multiplatform water bath for 3 days. Acute lung inflammation was induced by lipopolysaccharide (LPS; 5 mg/kg). Melatonin (5 mg/kg) and LPS was administered in SD mice at day 2. Mice were divided into five groups as control, SD, LPS, LPS + SD, and LPS + SD + melatonin (each group, n = 11). Mice were killed on day 3 after treatment of melatonin and LPS for 24 hr. Lung tissues were collected for histological examination and protein analysis. The malondialdehyde (MDA) level was determined for the effect of oxidative stress. Melatonin restored weight loss in LPS + SD. Histological findings revealed alveolar damages with inflammatory cell infiltration in LPS + SD. Melatonin remarkably attenuated the alveolar damages. In western blot analysis, LPS reduced the levels of Bcl-XL and procaspase-3 in SD mice. After treatment with melatonin, the levels of Bcl-XL and procaspase-3 increased when compared with LPS + SD. LPS treatment showed an increase of TUNEL-positive cells, whereas melatonin prevented the increase of cell death in LPS + SD animals. In lipid peroxidation assay, melatonin significantly reduced the elevated MDA level in LPS + SD. Our results suggest that melatonin attenuates acute lung inflammation during SD via anti-apoptotic and anti-oxidative actions.

Lead exposure increases oxidative stress in the gastric mucosa of HCl/ethanol-exposed rats

AIM: To investigate the role of reactive oxygen species in the ulcer-aggravating effect of lead in albino rats.

METHODS: Albino Wistar rats were randomly divided into three groups and treated orally with 100 mg/L (low dose) or 5000 mg/L (high dose) of lead acetate for 15 wk. A third group received saline and served as control. At the end of wk 15, colorimetric assays were applied to determine the concentrations of total protein and nitrite, the activities of the oxidative enzymes catalase and superoxide dismutase, and lipid peroxidation in homogenized gastric mucosal samples.

RESULTS: Exposure of rats to lead significantly increased the gastric mucosal damage caused by acidified ethanol. Although the basal gastric acid secretory rate was not significantly altered, the maximal response of the stomach to histamine was significantly higher in the lead-exposed animals than in the unexposed control group. Exposure to low and high levels of lead significantly increased gastric lipid peroxidation to 183.2% ± 12.7% and 226.1% ± 6.8% of control values respectively (P < 0.0). On the other hand, lead exposure significantly decreased catalase and superoxide dismutase (SOD) activities and the amount of nitrite in gastric mucosal samples.

CONCLUSION: Lead increases the formation of gastric ulcers by interfering with the oxidative metabolism in the stomach.

Worsening effect of partial sleep deprivation on indomethacin-induced gastric mucosal damage

The present study was to investigate the roles of cyclooxygenase-1 and -2 (COX-1 and COX-2) and prostaglandin (PG) on gastric mucosal integrity of partially sleep deprived (PSD) rats. A slowly moving drum was used to induce PSD. The PG levels in the gastric mucosa of PSD rats, with or without indomethacin or rofecoxib treatment, were determined. Exogenous prostaglandin E (PGE) analog, misoprostol, was administered to PSD rats to investigate the modulating effect of PG in indomethacin-induced gastric damage. It was observed that COX-1 mRNA and protein were up-regulated in the gastric mucosa of PSD rats. Selective COX-2 inhibition by rofecoxib failed to decrease mucosal PGE2 levels nor to affect mucosal integrity in both PSD and sleep undisturbed rats. However, indomethacin, a COX-1 preferential non-selective COX inhibitor, significantly reduced mucosal PGE2 content and produced more severe mucosal damage in PSD rats than in the controls. The deleterious effect of indomethacin on gastric mucosal integrity of PSD rats was significantly attenuated with the administration of misoprostol. These results suggest that PSD enhances COX-1 biosynthesis of gastroprotective PGE2 as an adaptive response of the stomach to stress. The administration of non-selective COX inhibitors to subjects with chronic sleep deprivation may induce more gastric damages.