The germ-free mice monocolonization with Bacteroides fragilis improves azoxymethane/dextran sulfate sodium induced colitis-associated colorectal cancer.

Objective: Inflammatory bowel disease (IBD) is generally considered as a major risk factor in the progression of colitis-associated colorectal cancer (CAC). Previous studies have indicated that the composition of gut microflora may be involved in CAC induction and progress. Bacteroides fragilis (BF) is a Gram-negative anaerobe belonging to colonic symbiotic bacteria of the host. This study was aimed to investigate the protective role of BF in a colorectal cancer (CRC) model induced by azoxymethane (AOM) and dextran sulfate sodium (DSS) in germ-free (GF) mice. Materials and methods: Total 22 GF mice were divided into two groups: GF and BF group. Half of the GF mice were colonized with BF for 28 days before CRC induction by AOM/DSS. Results: BF colonization increased animal survival (100%). Cecum weight and cecum/body weight ratio significantly decreased in BF/AOM/DSS group. Interestingly, there was a significant decrease in tumor number and tumor incidence in the BF/AOM/DSS group as compared to the GF/AOM/DSS group. The adenocarcinoma/adenoma incidence and histologic score were also decreased in the BF/AOM/DSS group. In addition, immunohistochemistry staining found decreased numbers of cell proliferation (PCNA) and inflammatory cell (granulocytes) infiltration in the colon mucosa of the BF group. The ß-catenin staining in the BF/AOM/DSS group had fewer and weaker positive signal expressions. Taking together, the BF colonization significantly ameliorated AOM/DSS-induced CRC by suppressing the activity of cell proliferation-related molecules and reducing the number of inflammatory cells. Conclusions: Symbiotic BF may play a pivotal role in maintaining the gastrointestinal immunophysiologic balance and regulating anti-tumorigenesis responses.

Effects of Ganoderma lucidum and 'Essence of Chicken' on Physical Fatigue Recovery and Exercise Performance Improvement.

A fast-paced lifestyle, pressure from the environment and a heavy work load often cause extreme tiredness in modern life. Different kinds of nutritional supplements in the form of functional foods or traditional Chinese medicine, such as 'essence of chicken' and Ganoderma lucidum have been claimed to benefit physical performance and promote health. Previous studies have revealed that 'essence of chicken' or G. lucidum have a wide spectrum of biological activities. In this study, we combined these two ingredients together (designated as CEG) to evaluate their synergistic effects on physiological adaption on exercise fatigue and physical activities. The ICR strain mice were allocated as 0, 833, 1666, and 4165 mg/kg dose groups and administrated by oral gavage consecutively for 4 weeks. Physical activities including grip strength and aerobic endurance were evaluated. Various fatigue-associated biochemical variables such as lactate, BUN or CK were also evaluated. The levels of liver and muscle glycogen were measured as an indicator of energy storage at the end of the experiment. Safety assessments for supplementation were also evaluated. CEG supplementation significantly increased the endurance and grip strength and demonstrated beneficial effects on lactate production and clearance rate after an acute exercise challenge. The CEG supplementation significantly mitigated the BUN and CK indexes after extended exercise and elevated the glycogen content in the liver and muscle tissues. According to body composition, biochemical and histopathological data, daily administration of CEG for over 28 days (subacute toxicity) also demonstrated reasonable safety results for supplementation. Combined G. lucidum and 'essence of chicken' can significantly increase the exercise performance and improve fatigue recovery. It may also provide a viable alternative nutritional supplement for health promotion.

Effects of plant- and animal-based high-fat diets on lipid storage and distribution in environmental bacteria-colonized gnotobiotic mice.

Different edible oils such as lard and soybean oil have been reported to interact with the gut microbiota, affecting host lipid metabolism. However, whether bacteria derived from the environment influence host lipid metabolism remains unclear. This study aimed to clarify the roles of environmental bacteria in host lipid storage and distribution with various edible oils. Gnotobiotic C57BL/6JNarl mice were inoculated with Lysinibacillus xylanilyticus and Paenibacillus azoreducens and then fed either a normal diet (LabDiet 5010, control group) or a diet containing 60% lard (L-group) or soybean oil (S-group) for 18 months. Interestingly, the S-group accumulated massive amounts of white adipose tissue compared to the L- and control groups, while the L-group displayed more hepatic steatosis and fatty droplets than the other groups. The expression of fatty acid synthase (FAS), hydroxymethylglutaryl-coenzyme A reductase (HMGCR), sterol regulatory element-binding protein 2 (SREBP2), and peroxisome proliferator-activated receptor gamma (PPARγ) in the livers of the L-group were markedly elevated compared to the S-group. FAS and PPARγ protein levels were also markedly elevated. However, there were no differences in the expression of the pro-inflammatory cytokines interleukin-6 and tumor necrosis factor-α between the groups. Our results suggest that environmental bacteria may affect host hepatic inflammation and lipid distribution in the presence of high-fat diets, with different effects depending on the fat type consumed.

Antioxidative phytochemicals from Rhododendron oldhamii Maxim. leaf extracts reduce serum uric acid levels in potassium oxonate-induced hyperuricemic mice.

BACKGROUND: Some of the genus Rhododendron was used in traditional medicine for arthritis, acute and chronic bronchitis, asthma, pain, inflammation, rheumatism, hypertension and metabolic diseases and many species of the genus Rhododendron contain a large number of phenolic compounds and antioxidant properties that could be developed into pharmaceutical products. METHODS: In this study, the antioxidative phytochemicals of Rhododendron oldhamii Maxim. leaves were detected by an online HPLC-DPPH method. In addition, the anti-hyperuricemic effect of the active phytochemicals from R. oldhamii leaf extracts was investigated using potassium oxonate (PO)-induced acute hyperuricemia. RESULTS: Six phytochemicals, including (2R, 3R)-epicatechin (1), (2R, 3R)-taxifolin (2), (2R, 3R)-astilbin (3), hyposide (4), guaijaverin (5), and quercitrin (6), were isolated using the developed screening method. Of these, compounds 3, 4, 5, and 6 were found to be major bioactive phytochemicals, and their contents were determined to be 130.8 ± 10.9, 105.5 ± 8.5, 104.1 ± 4.7, and 108.6 ± 4.0 mg per gram of EtOAc fraction, respectively. In addition, the four major bioactive phytochemicals at the same dosage (100 mmol/kg) were administered to the abdominal cavity of potassium oxonate (PO)-induced hyperuricemic mice, and the serum uric acid level was measured after 3 h of administration. H&E staining showed that PO-induced kidney injury caused renal tubular epithelium nuclear condensation in the cortex areas or the appearance of numerous hyaline casts in the medulla areas; treatment with 100 mmol/kg of EtOAc fraction, (2R, 3R)-astilbin, hyposide, guaijaverin, and quercitrin significantly reduced kidney injury. In addition, the serum uric acid level was significantly suppressed by 54.1, 35.1, 56.3, 56.3, and 53.2 %, respectively, by the administrations of 100 mmol/kg EtOAc fraction and the derived major phytochemicals, (2R, 3R)-astilbin, hyposide, guaijaverin, and quercitrin, compared to the PO group. The administration of 10 mg/kg benzbromarone, a well-known uricosuric agent, significantly reduced the serum uric acid level by 45.5 % compared to the PO group. CONCLUSION: The in vivo decrease in uric acid was consistent with free radical scavenging activity, indicating that the major phytochemicals of R. oldhamii leave extracts and the derived phytochemicals possess potent hypouricemic effects, and they could be potential candidates for new hypouricemic agents.

Effect of intestinal microbiota on exercise performance in mice.

The antioxidant enzyme system helps protect against intense exercise-induced oxidative damage and is related to the physical status of athletes. Evidence suggests that intestinal microbiota may be an important environmental factor associated with host metabolism, physiology, and antioxidant endogenous defense. However, evidence of the effect of gut microbiota status on exercise performance and physical fatigue is limited. We investigated the association of intestinal bacteria and exercise performance in specific pathogen-free (SPF), germ-free (GF), and Bacteroides fragilis (BF) gnotobiotic mice. Endurance swimming time was longer for SPF and BF than GF mice, and the weight of liver, muscle, brown adipose, and epididymal fat pads was higher for SPF and BF than GF mice. The serum levels of glutathione peroxidase (GPx) and catalase were greater in SPF than GF mice. Serum superoxide dismutase activity was lower in BF than SPF and GF mice. In addition, hepatic GPx level was higher in SPF than GF and BF mice. Gut microbial status could be crucial for exercise performance and its potential action linked with the antioxidant enzyme system in athletes.

Different bacteria species lipopolysaccharide co-exposure with NASH diet exacerbate NASH and liver fibrosis progress in mice.

BACKGROUND AND AIM: Given the obesity epidemic, nonalcoholic fatty liver disease has become a public health concern; however, the progression mechanism remains obscure. Therefore, experimental nonalcoholic fatty liver disease/steatohepatitis (NASH) animal models that reflect human disease are necessary. In this study, we simulated the effects of gut microbiota imbalance on NASH and liver fibrosis. METHODS: Different bacterial sources of lipopolysaccharide, including Escherichia coli (GEC) and Salmonella abortus equi (GSE), were combined with a Gubra Amylin NASH (GAN) diet to induce NASH and liver fibrosis. RESULTS: Serum levels of alanine aminotransferase, hydroxyproline, CD68-positive cells, α-smooth muscle actin, and glial fibrillary acidic protein as well as TNF-α, COL1A1, TGF-ß, and NLRP3 expressions in the livers of the GSE group were markedly increased compared to those in the GAN group. The GAN diet with lipopolysaccharide (LPS) treatment resulted in a marked difference in microbiota α-diversity. The GSE group had higher numbers ofincreased Erysipelotrichaceae, Akkermansiaceae, and Bacteroidaceae families than the other groups. CONCLUSIONS: Based on these results, the GAN diet combined with LPS treatment successfully induced the progression of liver disease to NASH and fibrosis. With consistent histologically proven fibrosis, this obese NASH mouse model has relatively good clinical translatability and is highly applicable for preclinical drug testing for NASH.

Pretreatment with lipopolysaccharide ameliorates Pseudomonas exotoxin A-induced hepatotoxicity in rats.

CONTEXT: Liver injury can be induced by various hepatotoxicants, including Pseudomonas aeruginosa exotoxin A (PEA). Our previous study indicated that PEA-induced rat hepatotoxicity was T cells and Kupffer cells dependent. Several reports have demonstrated that non-toxic doses of bacterial lipopolysaccharide (LPS) can protect liver against the chemicals-induced toxicity such as acetaminophen and concanavalin-A. OBJECTIVE: This study aimed to investigate the protecting mechanisms of LPS on PEA-induced hepatotoxicity. RESULTS: Rats pretreated with LPS (40 µg/kg, 12 h before PEA admission) significantly decreased animal mortality, serum enzyme (ALT, AST and T-bil) activities, histopathological changes and hepatocytes apoptosis following challenge with PEA. The concentrations of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and interleukin-2 (IL-2) were reduced, but IL-6 and IL-10 were increased in the serum. In addition, prior treatment of these LPS-pretreated rats with gadolinium chloride (GdCl3), a selective Kupffer cell depletion agent, markedly enhanced liver injury after PEA administration. In contrast, the pretreatment of LPS to T-cell deficient athymic nude rats still display significant attenuation of PEA-induced liver injury. This observation further confirmed our hypothesis that LPS ameliorate PEA-hepatotoxicity was through Kupffer cells but not T cells. Moreover, LPS-induced hepatoprotection ability was neutralized by co-treatment with anti-TNF-α antibodies, but not with anti-IFN-γ antibodies. Finally, replacement of LPS with RS-LPS (Rhodobacter sphaeroides LPS), a Toll like receptor-4 (TLR-4) antagonist, resulted in severe hepatotoxicity. CONCLUSION: These results suggested that Kupffer cells, TNF-α and TLR-4 play central mediator roles during the hepatoprotection against PEA-induced hepatotoxicity conferred by LPS.

Cytoprotective effect of American ginseng in a rat ethanol gastric ulcer model.

Panax quinquefolium L. (American Ginseng, AG) is one of the most popular herbal medicines in the World. We aimed to investigate whether chronic (28-day) supplementation with AG could protect against ethanol-induced ulcer in gastric tissue. Furthermore, we investigated the possible molecular mechanisms leading to AG-mediated gastric mucosal protection. We randomized 32 male Wistar rats into four groups for treatment (n=8 per group): supplementation with water (vehicle) and low-dose (AG-1X), medium-dose (AG-2X) and high-dose (AG-5X) AG at 0, 250, 500, and 1250 mg/kg, respectively. In the first experiment, animals were fed vehicle or AG treatments for 4 weeks. At day 29, 75% ethanol was given orally to each animal at 10 mL/kg to induce gastric ulceration for 2 h. In a second experiment, animals were pretreated orally with each treatment for 1 hr before a single oral administration of ethanol (70%, 10 mL/kg). Trend analysis revealed that AG treatments inhibited ethanol-induced gastric mucosal damage. AG supplementation dose-dependently decreased the pro-inflammatory levels of interleukin 1ß and cyclooxygenase 2 and the expression of pro-apoptotic proteins tBid, cytochrome C, and caspases-9 and -3 and increased the levels of anti-apoptotic proteins Bcl-2, Bcl-xL and p-Bad. AG could have pharmacological potential for treating gastric ulcer.

Circulating gut microbiota-related metabolites influence endothelium plaque lesion formation in ApoE knockout rats.

Atherosclerosis is the main cause of cardiac and peripheral vessel infarction in developed countries. Recent studies have established that gut microbiota and their metabolites play important roles in the development and progression of cardiovascular disease; however, the underlying mechanisms remain unclear. The present study aimed to investigate endothelium plaque lesion formation in ApoE-deficient rats fed a normal chow diet under germ-free (GF) and specific-pathogen-free (SPF) conditions at various time points. There was no difference in serum cholesterol and triglyceride levels between SPF-rats and GF-rats. Histological studies revealed that the GF-rats developed endothelium plaques in the aorta from 26 to 52 weeks, but this was not observed in SPF-rats. GF-rat coronary arteries had moderate-to-severe endothelium lesions during this time period, but SPF-rat coronary arteries had only mild lesion formation. Immunohistochemical staining showed higher accumulation of CD68-positive and arginase-negative foamy-like macrophages on the arterial walls of GF-rats, and expression of TNF-α and IL-6 in foam cells was only observed in GF-rats. In addition, microbial metabolites, including equol derivatives, enterolactone derivatives, indole-3-propionate, indole-3-acrylic acid, cholic acid, hippuric acid, and isoquinolone, were significantly higher in the SPF group than in the GF group. In conclusion, our results indicate that gut microbiota may attenuate atherosclerosis development.

Organic cation transporter 2 activation enhances sensitivity to oxaliplatin in human pancreatic ductal adenocarcinoma.

Oxaliplatin, a third-generation platinum derivative, has become one of the main chemotherapeutic treatments for esophagus, gastric and colorectal cancer; however, it is still unclear the potential effectiveness for pancreatic ductal adenocarcinoma (PDAC) with gemcitabine resistance. Here, we observed that PDAC tumors have low level of organic cation transporter 2 (OCT2, also known as SLC22A2) compared with non-tumor tissues and identified that OCT2 expression is positively correlated with oxaliplatin sensitivity in PDAC cells. Treatment of OCT2 inhibitors or knockdown of OCT2 expression significantly decreased the sensitivity to oxaliplatin in PANC-1 cells. In addition, bisulfite sequencing polymerase chain reaction analysis revealed that higher methylation frequency represses OCT2 expression in gemcitabine-resistant PANC-1 (PANC-1/GR) cells. Moreover, we found that treatment of DNA methyltransferase (DNMT) inhibitors, decitabine or 5-azacytidine recover OCT2 expression and oxaliplatin sensitivity in PANC-1/GR cells, and DNMT1 level has inverse correlation with OCT2 expression in PDAC cells and tumors. Our findings jointly suggest that OCT2 expression is a potential and predictive marker for evaluating oxaliplatin sensitivity and developing alternative treatments for PDAC patients with gemcitabine resistance.

Combination of Treadmill Aerobic Exercise with Bifidobacterium longum OLP-01 Supplementation for Treatment of High-Fat Diet-Induced Obese Murine Model.

INTRODUCTION: Obesity, which can result from disease, genetics, nutrition, lifestyle, and insufficient physical activity, substantially increases an individual's risk of complications and comorbidities. Exercise can be an effective strategy for achieving an energy balance and physiological fitness as part of obesity management. Additionally, probiotics, which are isolated from food and the environment, are being rapidly developed and have functional benefits for mitigating various metabolic dysfunctions associated with obesity. The potentially positive physiological and functional effects of exercise, probiotics, and exercise combined with probiotics should be elucidated in a model of diet-induced obesity. METHODS: Bifidobacterium longum subsp. longum OLP-01 (OLP-01) was isolated from an elite Olympic-level athlete who exhibited physiological adaptations to peripheral fatigue caused by exercise training. In this current study, ICR strain mice were fed a high-fat diet (HFD) for 4 weeks to replicate an obesity model. The mice were divided into 5 groups according to the diet administered: control with normal diet, only HFD, HFD + exercise, HFD + OLP, and HFD + exercise + OLP groups. They were administered the probiotic and/or treadmill exercise training for 5 weeks, and their growth curve, physical activity, physiological adaptation, biochemical parameters, body composition, and glucose tolerance were assessed. RESULTS: Compared with only exercise or only probiotics, a combination of probiotics and exercise significantly improved the weight, glucose tolerance, fat composition, and exercise-related oxidative stress of mice. Regular and programmed exercise with sufficient rest may be crucial to obesity improvement, and a combination of probiotics and exercise may synergistically assist obesity management and health promotion. CONCLUSION: OLP-01 probiotics combined with exercise training can be employed as a strategy for treating obesity. However, the exact regulatory mechanisms underlying this effect, possibly involving microbiota and associated metabolites, warrant further investigation.

Aldehyde Dehydrogenase Mutation Exacerbated High-Fat-Diet-Induced Nonalcoholic Fatty Liver Disease with Gut Microbiota Remodeling in Male Mice.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a critical enzyme involved in ethanol clearance in acetaldehyde metabolism and plays a key role in protecting the liver. The ALDH2*2 mutation causes a significant decrease in acetaldehyde scavenging capacity, leading to the accumulation of acetaldehyde after consuming alcohol. The prevalence of the ALDH2*2 variant is in 45% of Taiwanese individuals. ALDH2 reportedly has protective properties on myocardial damage, stroke, and diabetic retina damage. However, the effects of ALDH2 in the modulation of metabolic syndromes remain unclear. This study evaluates the roles of ALDH2 in a high-fat-diet-induced metabolic syndrome in mice. Male (M) and female (F) wild-type (WT) and ALDH2 knock-in C57BL/6J mice (4-5 weeks old) were fed a high-fat diet for 16 weeks. Results showed that the body and white-adipose-tissue weights were significantly increased in ALDH2-M compared to those in the other groups. We observed markedly elevated serum levels of alanine transaminase and glucose. Oral glucose-tolerance test and homeostasis-model assessment of insulin resistance (HOMA-IR) values were significantly higher in ALDH2-M mice than those in WT-M mice, with no observable differences in female mice. Abundant steatosis and inflammatory cells were observed in ALDH2-M, with significantly decreased expression of hepatic genes IRS2, GLUT4, and PGC-1α compared to that in WT-M. ALDH2 gene mutation also affected the ß-diversity of gut microbiota in ALDH2-M resulting in the decreased abundance of Actinobacteria and an increase in Deferribacteres. Our results suggest that potential changes in gut microbiota may be associated with the defective ALDH2 exacerbation of high-fat-diet-induced liver diseases in male mice. However, female mice were not affected, and sex hormones may be an important factor that requires further investigation.

Toll-like receptor 4 prevents AOM/DSS-induced colitis-associated colorectal cancer in Bacteroides fragilis gnotobiotic mice.

Bacteroides fragilis (BF) plays a critical role in developing and maintaining the mammalian immune system. We previously found that BF colonization could prevent inflammation and tumor formation in a germ-free (GF) colitis-associated colorectal cancer (CAC) mouse model. The role of Toll-like receptor 4 (TLR4) in CAC development has not been clearly elucidated in BF mono-colonized gnotobiotic mice. The wild-type (WT) and TLR4 knockout (T4K) germ-free mice were raised with or without BF colonization for 28 days (GF/WT, GF/T4K, BF/WT, and BF/T4K) and then CAC was induced under azoxymethane (AOM)/dextran sulfate sodium (DSS) administration. The results showed that tumor formation and tumor incidence were significantly inhibited in the BF/WT group compared to those observed in the GF/WT group. However, the tumor prevention effect was not observed in the BF/T4K group unlike in the BF/WT group. Moreover, the CAC histological severity of the BF/WT group was ameliorated, but more severe lesions were found in the GF/WT, GF/T4K, and BF/T4K groups. Immunohistochemistry showed decreased cell proliferation (PCNA, ß-catenin) and inflammatory markers (iNOS) in the BF/WT group compared to those in the BF/T4K group. Taken together, BF mono-colonization of GF mice might prevent CAC via the TLR4 signal pathway.

Different Parts of the Chicken Embryo Egg Improve D-Galactose-Induced Aging in a Mice Model.

Chick (CE) or duck embryo eggs are known for nutritional supplement foods in traditional East countries for physical fitness enhancement and postpartum conditioning for many years. In this study, we evaluated the effects of different parts of the 10-day CE (embryo: CEr, yolk: CEw, and chorioallantoic membrane: CEp) on the antifatigue and antiaging activities in a D-galactose- (D-gal) induced aging mice model. The results showed CEp obviously increased the muscle weight and the liver and muscle glycogen content and enhanced exercise performance. In the antiaging assay, CEp significantly increased the activity of superoxide dismutase (SOD) and Glutathione Peroxidase (GPx). Moreover, the immunohistochemistry results of NRF-2 and HO-1 were also detected in the livers of mice in the D-gal/CEp group. The only partially potential such as CEr might improve OFT function with TG level, and CEw had strange grip strength. Therefore, we suggest that CEp has a potent antifatigue ability and could minimize the occurrence of age-associated disorders, more than other parts of the 10 days chicken embryo egg.

The novel camptothecin derivative, CPT211, induces cell cycle arrest and apoptosis in models of human breast cancer.

OBJECTIVE: Breast cancer is the second leading cause of cancer deaths in women worldwide and represents a highly aggressive nature with limited therapeutic options; thus, investigating novel therapeutic agents for breast cancer is much needed. In this study, we investigated the anticancer effects of a novel camptothecin derivative, CPT211, against human breast cancer. METHODS: We used hormone receptor-positive MCF-7, triple-negative (TNBC) MDA-MB-231, and HER2-positive BT-474 human breast cancer cells to examine cytotoxicity of CPT211. We measured cell viability with dose dependence of CPT211 treatments by an MTT assay and investigated the potential underlying mechanism through flow cytometric and Western blot methods. Furthermore, we evaluated the efficacy of the treatment combination of CPT211 and doxorubicin in a mouse model bearing MDA-MB-231 xenografts. RESULTS: CPT211 treatment led to dose-dependent decreases in cell viability of both MCF-7 and MDA-MB-231 cells, but not BT-474 cells. Analysis of the underlying molecular mechanism revealed that CPT211 activated p53-mediated apoptosis, by triggering intrinsic and extrinsic apoptotic pathways in MCF-7 cells. Additionally, CPT211 induced apoptosis and cell cycle arrest of MDA-MB-231 cells by activating Fas/FADD/caspase-8 signaling, suggesting that CPT211-mediated MDA-MB-231 cell apoptosis may occur through an extrinsic apoptosis pathway. CPT211 treatment with doxorubicin in mice bearing MDA-MB-231 xenografts was shown to enhance caspase-8 and caspase-7 activation, resulting in significant inhibition of tumor growth. CONCLUSIONS: These results indicate that Fas/FADD/caspase-8 activation plays an important role in CPT211-mediated tumor growth suppression in TNBC, and the novel camptothecin derivative, CPT211, can be exploited for specific targeted therapies and potentially improve approaches to combination treatments for human breast cancer.

Housing condition-associated changes in gut microbiota further affect the host response to diet-induced nonalcoholic fatty liver.

Diet-induced obesity is the most widely used animal model for studying nonalcoholic fatty liver disease (NAFLD). However, the physiological effects of a high-fat diet (HFD) are inconsistent between different studies. To elucidate this mystery, mice raised with conventional (CONV), specific pathogen-free (SPF) and gentamicin (G) treatments and fed with standard diet (STD) or HFD were analyzed in terms of their physiology, gut microbiota composition, hepatic steatosis and inflammation. Serum biochemistry showed increased levels of cholesterol and aspartate aminotransferase in the G-STD and CONV-HFD groups, respectively. The CONV-HFD group exhibited more inflammatory foci compared to the SPF-HFD and G-HFD groups. Furthermore, immunohistochemistry staining revealed the infiltration of Kupffer cells in the liver, consistent with increased mRNA levels of MCP-1, CD36 and TLR4. Principal coordinate analysis and the cladogram of LEfSe showed that the distinguished clusters of gut microbiota were dependent on housing conditions. The Rikenellaceae, F16 and Desulfovibrionaceae were strongly correlated with hepatic inflammation. Otherwise, higher NAFLD activity score correlated with altered relative abundances of Bacteroidetes and Firmicutes. In conclusion, gut microbiota varying with housing condition may be pivotal for the host response to HFD.

Different bacteria species lipopolysaccharide co-exposure with Pseudomonas exotoxin A on multiple organ injury induction.

The present study investigated the effect of different bacterial species lipopolysaccharide plus Pseudomonas exotoxin A (LPS/PEA) on the induction of multiple organ injury (MOI). Rats were injected with various LPS from Salmonella (SAE, SAT), E. coli (EB4, EB5), or P. aeruginosa (PAL) and PEA showed a greater mortality in the SAE/PEA and SAT/PEA groups. Histological alterations, serum enzymes, and cytokines changes were severer in the SAE/PEA group than the EB4/PEA or PAL/PEA group. EB4/PEA and PAL/PEA failed to induce MOI, even at the LPS doses increased up to 2-4- and 4-8-fold, respectively. Rats co-treated with Salmonella lipid A/PEA developed severer MOI than the E. coli lipid A/PEA. The results indicated the critical roles of MOI induction, which were related to LPS derived from appropriate bacterial species.

Co-exposure of lipopolysaccharide and Pseudomonas aeruginosa exotoxin A-induced multiple organ injury in rats.

Pseudomonas aeruginosa Exotoxin A (PEA) induces hepatotoxicity in experimental animals. Lipopolysaccharide (LPS) interacts synergistically with xenotoxics to induce severe organ injury. We examined the combination of non-injurious doses of LPS and sub-hepatotoxic PEA in the induction of multiple organ injury (MOI). Rats treated with 20 or 40 microg/kg LPS plus 10 microg/kg PEA developed severe liver, kidney, and lung injury; elevation of TNF-alpha, IFN-gamma, and IL-2; and high mortality. Depletion of Kupffer cells or T-cells by pretreatment with Gadolinium Chloride or FK506, respectively, attenuated MOI. Thus LPS + PEA acted synergistically on Kupffer and T-cells to induce proinflammatory cytokines contributing to MOI.

Pseudomonas aeruginosa exotoxin A-induced hepatotoxicity: an animal model in rats.

Pseudomonas aeruginosa exotoxin A (PEA) has been generally used to induce liver injury in mice for experimental study. No PEA-induced hepatotoxicity study has ever been conducted in rats, although rats are the most common rodents used in toxicologic bioassay and pharmacological evaluation. The present study was conducted in male Wistar rats that were injected (i.v.) with PEA at doses of 0, 10, 20, 30 or 40 microg/kg body weight and evaluated at 12, 24, 36, 48 and 60 hr post-exposure (HPE). Rats exposed to PEA at 40 microg/kg died before 36 HPE, and the mortality was dose and time dependent. Liver injury was noted as increases in serum enzymes, along with alterations of liver histology in the 40 microg/kg group at 12 HPE. TUNEL-positive staining indicative of hepatocyte apoptosis was observed in the 20 microg/kg group at 12 HPE. Significant levels of DNA fragmentation ladder were observed in the 30 microg/kg group starting at 24 HPE. Serum levels of TNF-alpha was increased in the 30 and 40 microg/kg groups at 48 and 24 HPE, respectively. Other cytokines, such as IL-2, IL-6, and IL-10 were also increased at various doses and times. Furthermore, the elevated serum hepatic index levels decreased significantly by dexamethasone pretreatment. In contrast, these markers were exacerbated by co-administration of a non-toxic dose LPS. In overall evaluation, the PEA-induced liver injury can be used as a model for study of hyperimmune-mediated hepatotoxicity.

Influence of age on susceptibility to Pseudomonas aeruginosa exotoxin A-induced hepatotoxicity in Long-Evans rats.

Epidemiological investigations suggest that increased age is associated with susceptibility to infection. Pseudomonas aeruginosa (P. aeruginosa) infection and associated exotoxin A (PEA) toxicity have been reported in hospitalized elderly patients and young children with cystic fibrosis. The present study investigated age-related differences in PEA-induced hepatotoxicity in post weaning (PW, 3 weeks), young adult (YA, 12 weeks), and mature adult (MA, 60-64 weeks) rats. PEA (20 microg/kg) was injected intraveneously and mortality, clinical chemistry, hepatic histopathology, TUNEL (Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling) and PCNA (Proliferating cell nuclear antigen) staining, and serum cytokine levels were assessed at specific time points, up to 72 hr post-exposure (HPE). Mortality in MA rats was 100% at less than 48 HPE. Serum ALT levels in MA rats were approximately 5-fold greater than levels in PW and YA rats at 36 HPE. MA rat liver histological sections showed diffuse hepatocellular necrosis. In contrast, hepatocellular apoptosis, demonstrable by the TUNEL method, was noted simply in the periportal and midzonal regions from 36 to 48 HPE. Increased morphological mitoses and PCNA-positive hepatocytes were seen in PW and YA rats at 72 HPE. These parameters were correlated with age-dependent significant increases in TNF-alpha, IL-2, IL-6, and IL-18 levels. These data suggest that inflammatory cytokines play an important role in age-related differences in PEA-induced hepatotoxicity. Moreover, these cytokines might correlate with different patterns histopathologic features at various ages.