Rat Cecum Research Articles

The impact of moderate- and high-intensity exercise on microbiota population and short-chain fatty acid production in the cecum of rats

The body’s immunity can be increased by physical exercise. High-intensity physical exercise (HIPE) can disturb the body’s digestive system and cause an imbalance of the microbiome population between pathogenic and nonpathogenic bacteria. This posttest-only control group study was conducted on 18 male Wistar rats which were divided into three groups (n = 6): (1) control (nonexercised); (2) moderate-intensity physical exercise (MIPE) (30 minutes at 55%VO2 max/day, 5 days per week); and (3) high-intensity physical exercise (HIPE) (30 minutes at 85% VO2 max/day, 5 days per week). After 5 weeks, subjects’ cecum was isolated from the gut and colony-forming units were counted for the total lactic acid bacteria, Lactobacillus spp., and Escherichia coli. Microbiological analysis of the cecal contents indicated that, in comparisons between the control, the MIPE, and the HIPE groups, there were no statistically significant differences between the bacterial groups except for E. coli between the MIPE and HIPE groups (p < 0.05). Additionally, the MIPE group showed a significantly higher acetate and propionic acid concentration compared to the HIPE and control groups (p < 0.05). Moderate but not high-intensity exercise may contribute to better well-being of the microbiota environment as shown by the significantly higher acetic and propionic acid production.

CART Peptides Differently Regulate Firing Rates and GABAergic Synaptic Inputs of DMV Neurons Innervating the Stomach Antrum and Cecum of Adult Male Rats

Background/Aim: Central administration of cocaine- and amphetamine-regulated transcript peptides (CARTp) alters gastrointestinal motility and reduces food intake in rats. Since neurons in the dorsal motor nucleus of the vagus (DMV) receive GABAergic and glutamatergic inputs and innervate the smooth muscle of gastrointestinal organs, we hypothesized that CARTp acts on the DMV or presynaptic neurons. Methods: We used 3,3′-dioctadecyloxa-carbocyanine perchlorate (DiO) retrograde tracing with electrophysiological methods to record DMV neurons innervating the stomach antrum or cecum in brainstem slices from adult rats. Results: DiO application did not change the electrophysiological properties of DMV neurons. CART_55–102 had no effect on the basal firing rates of neurons in either the stomach antrum-labeled group (SLG) or cecum-labeled group (CLG). When presynaptic inputs were blocked, CART_55–102 further increased the firing rates of the SLG, suggesting a direct excitatory effect. Spontaneous inhibitory postsynaptic currents (sIPSCs) occurred at a higher frequency in SLG neurons than in CLG neurons. CART_55–102 reduced the amplitude and the frequency of sIPSCs in SLG neurons dose-dependently, with higher doses also reducing spontaneous excitatory postsynaptic currents (sEPSCs). Higher doses of CART_55–102 reduced sIPSC and sEPSC amplitudes in CLG neurons, suggesting a postsynaptic effect. In response to incremental current injections, the SLG neurons exhibited less increases in firing activity. Simultaneous applications of current injections and CART_55–102 decreased the firing activity of the CLG. Therefore, stomach antrum-projecting DMV neurons possess a higher gating ability to stabilize firing activity. Conclusion: The mechanism by which CARTp mediates anorectic actions may be through a direct reduction in cecum-projecting DMV neuron excitability and, to a lesser extent, that of antrum-projecting DMV neurons, by acting on receptors of these neurons.

Anti-Adhesive Effect of Porous Polylactide Film in Rats.

Excessive adhesion between tissues on a significant area can cause the development of disorders, cosmetic problems, and ileus. Methods for preventing adhesion include the use of drugs and anti-adhesion barriers for physical blocking. In this study, the adhesion prevention effect of polylactide film in porous form was analyzed. A porous polylactide film was manufactured using a molecular weight of at least 100,000. To generate porosity, 98% methylene chloride and 95% ethyl alcohol were used as solvents. The thickness, surface, and internal pore shape of film were investigated. The crystal structures and melting temperature of film were measured. In the rat model, the presence and severity of adhesion were then analyzed. The thickness of the film ranged from 10 to 20 µm. The surface of the film contained pores with diameters of less than 10 µm. Partial crystallinity appeared from 15° to 20°, but the structure was amorphous overall. In the rat cecum abrasion model, adhesion occurred in 3 of the 13 rats in the polylactide experimental group, representing a 23.1% incidence rate. There were statistically significant differences in the severity of adhesion. The use of porous polylactide films can reduce the incidence of adhesion.

Study on the mechanisms of the intestinal tight-junction destruction caused by Blastocystis hominis infection in rats

To explore the mechanism of the intestinal barrier damage caused by Blastocystis hominis infections in rats. Thirty SD rats were randomly divided into the control group, and the 1-, 3-, 6- and 9-week-infection groups, of 6 rats in each group. Rats in each infection group were orally infected with B. hominis trophozoites at a density of 2 × 108 parasites per rat, and the control group was given an equal volume of phosphate buffered saline solution. The 7-hour urine samples were collected 1, 3, 6 and 9 weeks post-infection for the measurement of the intestinal permeability. Then, rats were sacrificed using the cervical dislocation method, and the cecum specimens were collected for the detection of the intestinal epithelial cell permeability. The expression of tight junction-related Occludin and Claudin - 1 genes and apoptosis-related Bcl - 2 and Bax genes was quantified in cecum epithelial cells using the real-time fluorescent quantitative PCR (qPCR) assay, and cell apoptosis was detected in the rat cecum using the TdT-mediated dUTP nick-end labeling (TUNEL) assay. The median urinary lactolose to mannitol ratios were 0.29, 0.72, 0.44, 0.46 and 0.38 in the control group, and the 1-, 3-, 6- and 9-week-infection groups, respectively, and the difference was statistically significant (H = 12.09, P < 0.05). B. hominis invasion and epithelial injury were observed in intestinal epithelial cells of rats infected with B. hominis, and transmission electron microscopy displayed the destruction of tight junctions between intestinal epithelial cells. The relative expression of Occludin, Claudin-1, Bcl-2 and Bax genes was 1.04, 0.62, 0.71, 0.68 and 0.96; 1.03, 0.61, 0.63, 0.76 and 0.86; 1.08, 0.70, 0.75, 0.74 and 1.03; and 1.00, 1.57, 1.33, 1.35 and 1.10 in the control group and the 1-, 3-, 6- and 9-week-infection groups, respectively, and all differences were statistically significant (F = 2.86, 2.85, 3.37 and 4.45, all P values < 0.05). The median number of positive staining cells were 1.00, 13.00, 9.00, 3.50 and 1.00 in rat cecum specimens in the control group, and the 1-, 3-, 6- and 9-week-infection groups, respectively, and the difference was statistically significant (H = 22.95, P < 0.01). B. hominis infection may cause an increase in the rat intestinal permeability through triggering the apoptosis of intestinal epithelial cells to destroy the tight junction between intestinal epithelial cells, thereby destroying the intestinal barrier function.

Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum

Abstract Background Lignocellulose is considered a renewable organic material, but the industrial production of biofuel from lignocellulose is challenging because of the lack of highly active hydrolytic enzymes. The guts of herbivores contain many symbiotic microorganisms that have evolved to hydrolyze plant lignocellulose. Chinese bamboo rats mainly consume high-fiber foods, indicating that some members of the intestinal tract microbiota digest lignocellulose, providing these rats with the energy required for growth. Results Here, we used metagenomics to analyze the diversity and functions of the gut microbiota in Chinese bamboo rats. We identified abundant populations of lignocellulose-degrading bacteria, whose main functions involved carbohydrate, amino acid, and nucleic acid metabolism. We also found 587 carbohydrate-active enzyme genes belonging to different families, including 7 carbohydrate esterase families and 21 glycoside hydrolase families. The glycoside hydrolase 3, glycoside hydrolase 1, glycoside hydrolase 43, carbohydrate esterase 4, carbohydrate esterase 1, and carbohydrate esterase 3 families demonstrated outstanding performance. Conclusions The microbes and enzymes identified in our study expand the existing arsenal of proficient degraders and enzymes for lignocellulosic biofuel production. This study also describes a powerful approach for targeting gut microbes and enzymes in numerous industries. How to cite: Bai D, Lin X, Hu Y, et al. Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum. Electron J Biotechnol 2021;50. https://doi.org/10.1016/j.ejbt.2020.12.001

Regional Differences in the Gut Microbiota and Gut-Associated Immunologic Factors in the Ileum and Cecum of Rats With Collagen-Induced Arthritis.

Rheumatoid arthritis (RA) is a common autoimmune disease characterized by chronic inflammation and a multifactorial etiology. We previously showed that gut microbiota dysbiosis in the rat ileum is involved in the development of collagen-induced arthritis (CIA). The gut microbiota in the distinct gastrointestinal tract (GIT) plays region-specific roles, but information on the different roles of the microbiota in distinct GIT compartments of CIA rats is limited. This study aimed to evaluate the region-specific differences in the gut microbial communities and certain gut-associated immunologic factors in the ileum and cecum of CIA rats. Ileal and cecal digesta were collected from CIA and control rats for microbiome analysis. We determined the microbial richness, diversity and taxa as well as the expression of interleukin (IL)-1β and IL-17A in the epithelium and lamina propria of the ileum and cecum mucosal layers. The CIA-induced microbiota alterations in the ileum differed from those in the cecum. The ileal microbiota were more markedly influenced in CIA, as revealed by sharp reductions in the abundances of the families Enterococcaceae, Lactobacillaceae and Streptococcaceae and the genera Lactobacillus and Lactococcus. Moreover, significant increases in IL-1β, and IL-17A mRNA expression were detected in only the ileal epithelium and lamina propria of the mucosal layer. Therefore, the microbial characteristics in the ileum were consistent with the immune-mediated inflammatory features of CIA, suggesting that the ileal microbiota might better represent the CIA-induced inflammatory responses than the cecal microbiota and that these responses might partially impact the progression of RA by regulating intestinal mucosal immunity.

Mucin-Derived O-Glycans Act as Endogenous Fiber and Sustain Mucosal Immune Homeostasis via Short-Chain Fatty Acid Production in Rat Cecum

Intestinal mucins escape digestion and enter the large bowel where they are degraded by the microbiota. To what extent and how mucins impact large-bowel physiology remain unclear. This study examined the large-bowel fermentation characteristics of mucins and mucin-derived O-glycan sugars and whether they affect gut immunity. Mucin secretion from the terminal ileum was determined from feces of ileorectostomized male Wistar rats (age 6 wk) fed an AIN76-based control diet (CD) for 15 d (experiment 1). Normal male Wistar rats (age 6 wk; 4 wk for experiment 4) were fed CD±porcine stomach mucin (PM) at 6 or 12g/kg diet, equivalent to 1.5 and 3 times the daily mucin secretion, for 14 d (experiment 2); CD±N-acetylglucosamine (GlcNAc), fucose, or N-acetylneuraminic acid at 10g/kg diet for 14 d (experiment 3); or CD±PM (15g/kg diet) or GlcNAc (10g/kg diet) for 29 d (experiment 4). SCFAs, microbial composition, and cecal O-glycan content were assessed. IgA+ plasma cells and regulatory T cells and inflammatory cytokine expression in the cecum were evaluated (experiment 4). Daily mucin secretion corresponded to 43.2 μmol of O-glycans. Cecal O-glycan contents were comparable between CD- and PM-fed rats. PM-fed rats harbored more mucin-degrading bacteria. Cecal concentrations of acetate (+37%) and n-butyrate (+73%) were higher in 12-g/kg PM diet-fed rats versus CD (P<0.05). Among O-glycan sugars, only GlcNAc produced higher n-butyrate concentrations (+68%) versus CD (P<0.05), with increased numbers of butyrate-producing bacteria. GlcNAc increased the abundance of IgA+ plasma cells (+29%) and regulatory T cells (+33%) versus CD, whereas PM increased IgA+ plasma cells (+25%) (all P<0.05). GlcNAc and PM decreased expression of Tnfa (-30%, -40%) and Ifng (-30%, -70%) versus CD (all P<0.05). Mucin-derived O-glycans act as endogenous fiber and maintain mucosal immune homeostasis via large-bowel SCFA production in rats.

Effect of Calcium‐Fortified Potato Starch on Cecal Fermentation and Fat Accumulation in Rats

AbstractCalcium‐fortified potato starch (Ca‐PS) is fed to rats for four weeks, and the effects on cecal fermentation and lipid metabolism are evaluated. The relative abundance of Bifidobacterium pseudolongum in rat cecum is higher in the PS and Ca‐PS groups than in the control group. Cecal acetate content is higher in the Ca‐PS group than in the control, high‐amylose cornstarch (HAS), and PS groups, and is positively correlated with the relative abundance of B. pseudolongum. The relative abundance of the Clostridiaceae family is higher in the PS and Ca‐PS groups than in the control and HAS groups, and is positively correlated with the cecal n‐butyrate content and the molar proportion of n‐butyrate in total‐SCFA. Furthermore, the consumption of PS and Ca‐PS reduces the serum and hepatic triglyceride levels and mesenteric adipocyte area in rats. Therefore, Ca‐PS may have beneficial effects that enhance cecal fermentation, especially in terms of cecal acetate production, which further suppresses fat accumulation. This is the first study to report the physiological effects of Ca‐PS.

1-Kestose supplementation mitigates the progressive deterioration of glucose metabolism in type 2 diabetes OLETF rats

The fructooligosaccharide 1-kestose cannot be hydrolyzed by gastrointestinal enzymes, and is instead fermented by the gut microbiota. Previous studies suggest that 1-kestose promotes increases in butyrate concentrations in vitro and in the ceca of rats. Low levels of butyrate-producing microbiota are frequently observed in the gut of patients and experimental animals with type 2 diabetes (T2D). However, little is known about the role of 1-kestose in increasing the butyrate-producing microbiota and improving the metabolic conditions in type 2 diabetic animals. Here, we demonstrate that supplementation with 1-kestose suppressed the development of diabetes in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, possibly through improved glucose tolerance. We showed that the cecal contents of rats fed 1-kestose were high in butyrate and harbored a higher proportion of the butyrate-producing genus Anaerostipes compared to rats fed a control diet. These findings illustrate how 1-kestose modifications to the gut microbiota impact glucose metabolism of T2D, and provide a potential preventative strategy to control glucose metabolism associated with dysregulated insulin secretion.

Magnesium bioavailability of dried and thinly shaved kombu in rats.

Magnesium (Mg) is highly bioavailable in kombu compared with other edible seaweeds. However, a considerable amount of Mg is lost during industrial processing and cooking of kombu. We hypothesized that thinly shaved kombu (TSK), a traditional Japanese kombu product, is a suitable Mg source for daily diets because TSK hardly loses Mg during processing. Rats were fed diets containing TSK or magnesium oxide (MgO) to satisfy 25%, 50%, 75%, or 100% of their Mg requirements. We determined the relative Mg bioavailability of TSK compared to MgO and examined factors affecting Mg bioavailability in TSK. The relative bioavailability of Mg in TSK compared with MgO was calculated as 92.3%, 111.4%, and 87.2% from apparent absorption, urinary excretion, and femoral concentration of Mg, respectively. The ultrafiltrable Mg concentration was lower in the cecal content of rats given TSK than those given MgO. However, the mRNA expression of TRPM6, an Mg channel responsible for Mg absorption, was higher in the cecum of rats given TSK than those given MgO. Enhancement of TRPM6 expression in the large intestine negates the low bioaccessibility of Mg in TSK, and thus TSK shows Mg bioavailability comparable with MgO. © 2020 Society of Chemical Industry.

The Consumption of Galactomannan Effervescent Drinks made from Coconut Pulp Waste and Colonic Microbiota in Wistar Rats

The consumption of prebiotics is known to affect the balance of gut microbiota. The purpose of this study was to explore how a galactomannan-rich effervescent drink can affect the population of Lactobacillus, Bifidobacterium, E. coli, and the concentration of short-chain fatty acids in the cecum of rats. Twenty-eight male Wistar rats (aged 2 months) were divided equally into 7 groups and treated orally each day for 15 days with 2 mL effervescent drinks with increasing levels of prebiotic galactomannan. The dosage of 500 mg galactomannan increased the growth of Lactobacillus spp. and Bifidobacterium spp. with inhibition of the growth of E.coli with increased formation of short-chain fatty acids such as acetate, propionate, and butyrate in the cecum of rats.

235-LB: Postprandial Short-Chain Fatty Acid Concentrations in the Intestinal Lumen and Plasma

Obesity continues to be a global health risk affecting over 650 million adults worldwide. Fiber intake is negatively correlated with obesity, and increased fiber intake is associated with weight loss. Fiber is digested by the gut microbiota to produce short chain fatty acids (SCFA), which may have a beneficial effect on metabolic disease. While it is well known that SCFAs are mostly utilized by enterocytes as a fuel source, the timing of postprandial production and absorption of SCFAs from a meal, as well as the effect of high-fat feeding, has yet to be characterized. In the present study, we aimed to determine the levels of acetate, butyrate, and propionate, the major SCFAs, after a meal in rats maintained for 4wks on a chow, high-fat diet (45% kcal from fat; HFD) or HFD with 10% oligofructose (OFS), a well-studied prebiotic known to induce weight loss. SCFA levels were measured in the distal small intestine, cecum, and colon of rats, as well as the portal vein and vena cava at 0, 2, 4, 6, and 8 hours following consumption of an isocaloric meal of the maintenance diet. Chow rats had significantly increased levels of SCFAs as early as 2h postprandially, in the cecum, colon, portal vein, and vena cava compared to baseline levels, whereas HFD-fed rats displayed minimal increases in SCFAs. Addition of OFS rescued SCFA production, peaking at 4h postprandial; however, concentrations were not rescued to chow values at all timepoints. Increased body weight and adiposity was not associated with baseline SCFA levels in any compartment, but was negatively associated with postprandial SCFA levels in the cecum, colon, and portal vein. Overall, this study demonstrates that SCFAs exhibit a post-prandial rise similar to ingested macronutrients, and that baseline fasting levels of SCFAs may be an inaccurate indication of SCFA production in rodents. These data lay the groundwork for future studies to examine how rises in SCFA levels from breakdown of non-digestible carbohydrates can contribute to improve metabolic disease. Disclosure R. Meyer: None. A.I.L. Lane: None. A. Kangath: None. S.N. Weninger: None. T. Martinez: None. F. Duca: None.

Mucin-Derived O-Glycans Act as Endogenous Fiber and Sustain Mucosal Immune Homeostasis via Short-Chain Fatty Acid Production in Rat Cecum

Abstract Objectives Intestinal mucins escape digestion and enter the large bowel where they are degraded by microbiome. To what extent and how mucins impact large-bowel physiology remain unclear. This study examined the large-bowel fermentation characteristics of mucins and mucin-derived O-glycan sugars and whether mucins and N-acetylglucosamine (GlcNAc) affect gut immunity. Methods Mucin secretion from the terminal ileum was determined from feces of ileorectostomized male Wistar rats (age 6 weeks) fed AIN76-based control diet (CD) for 15 d (Expt. 1). Normal male Wistar rats (age 6 weeks; 4 weeks for Expt. 4) were fed CD ± porcine stomach mucin (PM) at 6 or 12g/kg diet, equivalent to 1.5 and 3 times daily mucin secretion, for 14 d (Expt. 2); CD ± GlcNAc, fucose, or N-acetylneuraminic acid at 10g/kg diet for 14 d (Expt. 3); or CD ± PM (15 g/kg diet) or GlcNAc (10 g/kg diet) for 29 d (Expt. 4). Short-chain fatty acids (SCFAs), microbial composition, and cecal O-glycan content were assessed. IgA+ plasma and regulatory T cells and inflammatory cytokine expression in the cecum were evaluated (Expt. 4). Results Daily mucin secretion corresponded to 43.2 mmol of O-glycans. PM was efficiently fermented in the cecum, as evidenced by comparable amounts of cecal O-glycans between groups. PM-fed rats harbored more mucin-degrading bacteria. Cecal SCFA concentrations, particularly n-butyrate, were higher in 12g/kg PM diet-fed rats versus CD (P &amp;lt; 0.05). Among O-glycan sugars, only GlcNAc produced higher n-butyrate concentrations versus CD (P &amp;lt; 0.05), with increased numbers of several butyrate-producing bacteria. GlcNAc increased the abundance of IgA + plasma and regulatory T cells versus CD (P &amp;lt; 0.05). PM produced a similar but less-significant trend. GlcNAc and PM feeding decreased expression of Tnfa and Ifng versus CD (P &amp;lt; 0.05). Conclusions Mucin-derived O-glycans act as endogenous fiber and maintain mucosal immune homeostasis via large-bowel SCFA production in rats. Funding Sources JSPS KAKENHI.

Effects of Various Concentrations of Trimethylamine‐N‐oxide on Serum and Cecal Metabolites in Female SD Rats Fed a High‐Fat Diet

Trimethylamine‐N‐oxide (TMAO) has been shown to be a putative promoter of cardiovascular disease. Trimethylamine (TMA) precursors, such as choline and L‐carnitine, in foods can be metabolized to TMA by some gut microbiota and further converted to TMAO in liver. Recently, gut microbiota has been found to play an important role in nutrient metabolism. It can metabolize not only nutrients but also bile acids, which could affect gut liver axis and modulate metabolism. However, the effects of various concentrations of TMAO on microbial metabolites including TMA, TMAO, individual bile acids, and short chain fatty acids in rats have been little studied. The aim of this study was to evaluate effects of dietary TMAO on levels of metabolites in serum (TMA, TMAO, and bile acids) and cecum (TMA, TMAO, bile acids, and short chain fatty acids) of female SD rats fed a high‐fat (HF) diet. Sixteen female SD rats were fed HF diet (AIN‐93G diet providing 45% of energy from fat) with or without various concentrations of TMAO (0.05%, 0.15%, and 0.3%; T0.05, T0.15, and T0.3, respectively) (w/w) in autoclaved tap water for 8 weeks. Levels of TMA, TMAO, and bile acids were determined by UPLC‐Synapt G2‐Si. Short chain fatty acid profile was determined by GC‐FID. Serum TMA and TMAO levels were significantly (p&lt;0.05) higher in the T0.3 than control group (CON), while cecal TMA level showed the opposite response. Glycocholic and tauro‐alpha‐muricholic acids were significantly (p&lt;0.05) higher in the serum of the T0.3 than that of the CON. Taurocholic and taurodeoxycholic acids were significantly (p&lt;0.05) the highest in the cecum of the CON. Valeric and isovaleric acids were significantly (p&lt;0.05) higher in the cecum of the T0.05 than that of the CON.Support or Funding InformationThis research has been supported by National Research Foundation of Korea (NRF‐2017R1D1A1B03028407) funded by the Ministry of Education of Korea.

Histopathological study of invasive and non-invasive Entamoeba spp. in experimental rats

BackgroundThe genus Entamoeba has many species that are invasive or non-invasive (E. histolytica, E. dispar, and E. moshkovskii).The invasive E. histolytica is the main pathogenic amoeba in human. Amoebiasis involves several stages starting with the adherence of the parasite to the intestinal epithelium, followed by degradation, tissue invasion, and distribution to other organs.ResultsThe current study investigates the pathological changes of Entamoeba spp. infection in both rectum and cecum of experimental rats. The results showed the histological changes at the 7th, 14th, and 28th day post-infection for the three species. E. histolytica and E. moshkovskii infection showed less pathological changes compared to E. histolytica. These changes include the attachment of the trophozoites to the mucosal layer, significant surface epithelial changes such as dissociation and degeneration in the mucosal layer, and ulceration of the apical surface. Inflammatory cells infiltrate the varied regions, extending into the deep mucosa causing mild architectural alterations. These are features of amoebiasis.ConclusionThe pathological changes reported in E. dispar and E. moshkovskii were less severe than E. histolytica.

A Short-Term Feeding of Dietary Casein Increases Abundance of Lactococcus lactis and Upregulates Gene Expression Involving Obesity Prevention in Cecum of Young Rats Compared With Dietary Chicken Protein.

Casein and chicken are assessed to contain high quality proteins, which are essential for human health. Studies have shown that ingestion of the two dietary proteins resulted in distinct effects on physiology, liver transcriptome and gut microbiota. However, its underlying mechanism is not fully understood, in particular for a crosstalk between gut microbiota and host under a specific diet intervention. We fed young rats with a casein or a chicken protein-based diet (CHPD) for 7 days, and characterized cecal microbiota composition and cecal gene expression. We found that a short-term intervention with a casein-based diet (CAD) induced a higher relative abundance of beneficial bacterium Lactococcus lactis as well as Bifidobacterium pseudolongum, which upregulated galactose metabolism of the microbiome compared with a CHPD. The CAD also upregulated gene expression involved in obesity associated pathways (e.g., Adipoq and Irs1) in cecal tissue of rats. These genes and the bacterial taxon were reported to play an important role in protecting development of obesity. Furthermore, the differentially represented bacterial taxon L. lactis was positively associated with these differentially expressed genes in the gut tissue. Our results provide a new insight into the crosstalk between gut microbiota and host in response to dietary proteins, indicating a potential mechanism of obesity prevention function by casein.

Effect of Lactobacillus casei on the depressive behavior and the expression of NR1 and NR2A receptors in hippocampus of rats with postpartum depression induced by maternal separation

Objective To investigate the effect of Lactobacillus casei on depressive behavior and the expression of NR1, NR2A receptor in postpartum depression rats induced by maternal separation. Methods Twenty-four Sprague-Dawley female rats were randomly divided into control group(CON group) (n=8), postpartum depression group(PPD group) (n=8), postpartum depression with lactobacillus casei group(PPD+ Lactobacillus casei group) (n=8). Rats of the control group were given no interventions.Rats in PPD group and PPD+ Lactobacillus casei group were given maternal separation to establish depression model.And then the rats in PPD+ Lactobacillus casei group were treated with Lactobacillus casei(8×108CFU/(kg·d)) for 4 weeks after 14 days of maternal separation.The forced swimming test (FST) was employed to detect the depressive behaviors.Lactobacillus, Bifidobacterium, Enterococcus faecalis and Escherichia coli in cecum of rats and the expression of NR1 and NR2A mRNA in hippocampus of rats were detected by real-time fluorescence quantitative PCR. Results Compared with CON group ((157.50±8.13) s), the immobility time of PPD group((200.00±10.35) s) was significantly longer (t=-3.23, P<0.05). Compared with PPD group, the immobility time of PPD+ Lactobacillus casei group ((153.25±7.41) s) was significantly shortened (t=3.67, P<0.05), and the depressive behavior was improved.Compared with CON group, the mRNA expression of Lactobacillus ((1.47±0.08), t=-5.87, P<0.01), Enterococcus faecalis ((1.23±0.08), t=-2.85, P<0.05) and Escherichia coli( (1.33±0.07), t=-4.96, P<0.01) in caecum were significantly increased in PPD group, while that of Bifidobacterium decreased significantly((0.65±0.07), t=5.18, P<0.01). Compared with PPD group, the mRNA expression of Lactobacillus( (1.05±0.05), t=3.67, P<0.01), Enterococcus faecalis ((0.97±0.05), t=2.74, P<0.05) and Escherichia coli ((1.06±0.05), t=3.31, P<0.01) were significantly decreased in PPD+ Lactobacillus casei group, while that of Bifidobacterium increased significantly ((0.98±0.04), t=-4.26, P<0.01). Compared with CON group, the mRNA expression of NR1 receptor ((0.57±0.04), t=9.65, P<0.01) and NR2A receptor ((0.60±0.05), t=8.64, P<0.05) in hippocampus of rats in PPD group were significantly decreased.Compared with PPD group, the expression of NR1 receptor ((1.01±0.05), t=-5.39, P<0.01) and NR2A receptor ((0.98±0.07), t=-3.91, P<0.05) in hippocampus were increased significantly in PPD+ Lactobacillus casei group. Conclusion Lactobacillus casei can improve the depressive behavior of postpartum depression in rats, and improve the intestinal flora, which affect the expression of NR1 and NR2A in hippocampus. Key words: Postpartum depression; Hippocampus; Intestinal flora; Lactobacillus casei; NR1 receptor; NR2A receptor; Rat

Chemical Modification of Cornstarch by Hydroxypropylation Enhances Cecal Fermentation‐Mediated Lipid Metabolism in Rats

AbstractHydroxypropylated (HP)‐cornstarch is fed to rats for 4 weeks and the effects on cecal fermentation and lipid metabolism are evaluated. In the cecum of rats fed either HP‐normal cornstarch (NCS) or HP‐waxy cornstarch (WCS), microbial composition is altered and the relative abundances of the Firmicutes and Bacteroidetes are decreased and increased, respectively, compared to high amylose cornstarch (HACS), NCS, and WCS groups. Cecal total‐short‐chain fatty acid (SCFA) content in the rats fed HP‐NCS and HP‐WCS is higher than the rats fed NCS and WCS. In HP‐NCS and HP‐WCS groups, cecal pH and mesenteric adipocyte area are decreased, and the plasma glucagon‐like peptide‐1 (GLP‐1) level and cecal mucin content are increased compared to HACS, NCS, and WCS groups. Plasma GLP‐1 level correlates positively with the cecal SCFA content and the serum insulin level, and negatively with the feed intake, while the adipocyte area positively correlates with the serum triglyceride level. Therefore, HP‐cornstarch may have possessed beneficial traits that enhance cecal fermentation and thereby influenced lipid metabolism, equally or greater than that of HACS.

Protective effects of microRNA-181b on aged rats with sepsis-induced hippocampus injury in vivo

To investigate the protective effect of microRNA-181b (miR-181b) on aged rats with sepsis-induced hippocampus injury in vivo. Seventy-five male healthy old Sprague-Dawley (SD) rats were randomly divided into five groups (n = 15) using a random number table: sham operation group (Sham group), sepsis group [cecal ligation and puncture (CLP) group], miR-181b Agomir+CLP group (Ag+CLP group), miR-181b Antagomir+CLP group (An+CLP group) and normal saline (NS) control group (NS+CLP group). Rats sepsis model was reproduced by CLP, and in Sham group, the cecum of rats was separated only after abdominal operation without ligation or perforation. The rats in Ag+CLP group were given miR-181b Agomir 10 μL via lateral ventricle at 24 hours before CLP, the rats in An+CLP group were given 10 μL miR-181b Antagomir, and those in NS+CLP group were given 10 μL NS. At 6, 12, 24 hours after CLP, 5 rats of each group were sacrificed randomly, and hippocampus were harvested. The expression of miR-181b in hippocampus was determined by real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The expression of nuclear factor-ΚB p65 (NF-ΚB p65) was determined by Western Blot. The contents of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were determined by enzyme-linked immunosorbent assay (ELISA). Compared with Sham group, the expression of miR-181b in hippocampus of CLP group was significantly decreased at 6 hours after CLP (2-ΔΔCT: 0.70±0.12 vs. 0.98±0.06, P < 0.05), and the expressions of NF-ΚB p65, IL-1β and TNF-α were significantly increased [NF-ΚB p65/Histone H3: 0.30±0.03 vs. 0.07±0.01, IL-1β (ng/L): 120.39±8.02 vs. 50.55±11.12, TNF-α (ng/L): 59.48±4.60 vs. 40.31±3.96, all P < 0.05], this trend was continued till 24 hours, and these results indicated that there was obvious inflammation in hippocampus of sepsis rats. There was no statistical difference in the expression of miR-181b, NF-ΚB p65, IL-1β or TNF-α in hippocampus between NS+CLP group and CLP group, which indicated that injection of NS into the rat lateral ventricle, had not aggravated the damage degree of hippocampus. Compared with CLP group, the expression of miR-181b in hippocampus of Ag+CLP group was significantly increased at 6 hours after CLP (2-ΔΔCT: 1.87±0.25 vs. 0.70±0.12, P < 0.05), and the expressions of NF-ΚB p65, IL-1β and TNF-α were significantly lowered [NF-ΚB p65/Histone H3: 0.16±0.03 vs. 0.30±0.03, IL-1β (ng/L): 73.76±8.17 vs. 120.39±8.02, TNF-α (ng/L): 49.52±4.77 vs. 59.48±4.60, all P < 0.05]. There was no statistical difference in the expression of miR-181b in hippocampus between An+CLP group and CLP group (2-ΔΔCT: 0.80±0.08 vs. 0.70±0.12 at 6 hours, 0.48±0.03 vs. 0.46±0.05 at 12 hours, 0.61±0.09 vs. 0.63±0.07 at 24 hours, all P > 0.05), but the expressions of NF-ΚB p65, IL-1β and TNF-α in hippocampus at 6 hours after CLP of An+CLP group were significantly higher than those of CLP group [NF-ΚB p65/Histone H3: 0.44±0.02 vs. 0.30±0.03, IL-1β (ng/L): 134.21±5.78 vs. 120.39±8.02, TNF-α (ng/L): 67.62±5.86 vs. 59.48±4.60, all P < 0.05], this trend was continued till 24 hours after CLP. The above results showed that overexpression of miR-181b might attenuate the inflammation of hippocampus through down-regulation of NF-ΚB, IL-1β and TNF-α. The expression of hippocampal miR-181b was significantly decreased in septic rats. Up-regulation of miR-181b could inhibit the activation of NF-ΚB signal pathway and the release of the inflammatory cytokine IL-1β and TNF-α stimulated by sepsis, and alleviate the inflammatory reaction and hippocampus injury in rat with sepsis.

Agave salmiana fructans as gut health promoters: Prebiotic activity and inflammatory response in Wistar healthy rats

Prebiotic effects of Agave salmiana fructans at five different doses were evaluated by the growth of Bifidobacterium, Lactobacillus, and Clostridium strains and SCFA production in the cecum and proximal colon of healthy Wistar rats. Mucosal integrity, bacterial proliferation, and inflammatory response were also examined. Growth of Bifidobacterium and Lactobacillus strains was improved by 12.5% doses of fructans in both cecum and proximal colon tissues, and a significant decrease of Clostridium (P < 0.05) was observed. Increases in mucosal thickness, proliferation, and cell adhesion were mainly observed in the cecum. High concentration of butyric acid and total SCFA were contained in the 12.5% doses. This study provides direct evidence of the prebiotic effects of Agave salmiana fructans, demonstrating that a diet supplemented with a 12.5% dose of fructans promotes major growth of probiotic bacteria and could be used as a potential prebiotic ingredient under the conditions used in this study. Taken together, these results further indicate the significance of Agave salmiana fructans as a prebiotic ingredient in the regulation and prevention of gastrointestinal diseases, as well as for the design of functional foods.