Rat Intestinal Mucosa Research Articles

Jiang Zhi Granule protects immunological barrier of intestinal mucosa in rats with non-alcoholic steatohepatitis

Context Jiang Zhi Granule (JZG) is known to improve hepatic function, reduce liver fat deposition and inflammation in non-alcoholic fatty liver disease (NAFLD). Objective To determine the protective mechanism of JZG on immunological barrier of intestinal mucosa in rats with diet-induced non-alcoholic steatohepatitis (NASH). Materials and methods A Sprague-Dawley (SD) model of NASH was established using a high-fat diet and 1% dextran sulphate sodium (DSS) through drinking water. The rats were randomized into four groups and treated for four weeks, respectively, including normal control (NC), model control (MC), positive control (PC) and JZG. Mesenteric lymph nodes (MLNs) cells were isolated and cultured to assess a potential disruption of the enteric immune barrier. Also, investigation of intestinal mucosal dendritic cell-toll-like-receptor-myeloid differentiation primary response 88 (DC-TLR-MyD88) signalling pathway in vitro was examined. Results The lethal concentration 50 (LD50) of JZG was greater than 5 g/kg, while its inhibitory concentration 50 (IC50) was 1359 μg/mL in HepG2. In JZG group, the plasma levels of alanine transaminase (ALT), aspartate transaminase (AST), malondialdehyde (MDA), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG) and serum endotoxin were significantly (p < 0.01) reduced. In contrast, plasma concentrations of high-density lipoprotein cholesterol (HDL-C) and superoxide dismutase (SOD) were increased. Furthermore, proinflammatory factor, interferon-γ (IFN-γ)+ from CD4+ T cells in DSS-induced NASH rats increased significantly (p < 0.01) compared to NC group. Importantly, JZG treatment substantially decreased (p < 0.01) the relative expressions of TLR-44 and MyD88. Conclusions JZG treatment may protect immunological barrier of intestinal mucosa in NASH individual.

УЛЬТРАСТРУКТУРНЕ ДОСЛІДЖЕННЯ КЛІТИН СЛИЗОВОЇ ОБОЛОНКИ ТОВСТОГО КИШЕЧНИКА ЩУРІВ ЗА ТРИВАЛОЇ ГІПЕРГАСТРИНЕМІЇ

Gastrin is considered one of the most important hormones regulating physiological processes. Trophic and proliferative effects of high gastrin levels on gastric mucosa are well known. Butinformation about gastrin effects on the colon is rather fragmentary and contradictory. In this study, ultrastructural changes in the proximal part of the colon induced in rats by chronic hypergastrinemia were analyzed by transmission electron microscopy. Experimental omeprazole-induced hypergastrinemia was reproduced using daily injections of proton pump inhibitor omeprazole in rats, resulted in hypersecrestion of gastrin by G-cells of stomach. Growth of gastrin level in the blood plasma was checked using radioimmunoassay method. Prolonged hypergastrinemia has been shown to be associated with increased cell proliferation and appearance of cellular atypia in the large intestine mucosa. The number of undifferentiated cells increased prominently. Intercellular contacts between such cells are altered, the space between them is unevenly expanded. Their organelles were observed significantly reduced, mitochondria contained destroyed crysts and signs of edema. Endocrinocytes did not contain their typical secretory granules. Cell nuclei were small, electron-dense, with invagination. In addition, numerous microorganisms were revealed in the intestinal lumen, as well as their invasion into the mucosa. Those ultrastructural changes were indicate increased hyperplastic processes and impaired cell differentiation in the epitheliocytes of large intestine. Therefore, long-term experimental hypergastrinaemia causes dysplastic changes in the large intestine mucosa of rats.

Comparison of the effects of the intestinal permeation enhancers, SNAC and sodium caprate (C10): Isolated rat intestinal mucosae and sacs

SNAC and C10 are intestinal permeation enhancers (PEs) used in formulations of peptides for oral delivery in clinical trials. Our aims were to compare their: (i) mechanism of action in isolated rat intestinal mucosae mounted in Ussing chambers and in non-everted gut sacs, (ii) effects on mucosa integrity in those models and also in in situ intra-jejunal instillations and (iii) interactions with intestinal mucus. SNAC increased the apparent permeability coefficient (Papp) of the paracellular marker, FITC-dextran 4000 (FD4), across isolated rat gastric mucosae in concentration-dependent fashion, whereas C10 did not, while both reduced the transepithelial electrical resistance (TEER). In isolated jejunal and colonic mucosae, both agents increased the Papp of [14C]-mannitol and FD4 whereas C10 but not SNAC reduced TEER. 20 mM SNAC was required to achieve the efficacy of 10 mM C10 in jejunal and colonic mucosae. In isolated non-everted jejunal and colonics sacs, FD4 flux increases were observed in the presence of both PEs. Histology of mucosae revealed that both PEs induced minor epithelial damage to the mucosa at concentrations that increased fluxes. Jejunal tissue withstood epithelial damage in the following order: intra jejunal in situ instillations > jejunal sacs > isolated jejunal mucosae. Both PEs modulated viscoelastic properties of porcine jejunal mucus without altering rheological properties. In conclusion, SNAC and C10 are reasonably efficacious PEs in rat intestinal tissue with common overall mechanistic features. Their potency and toxic potential are low, in agreement with clinical trial data.

Hyaluronic Acid in the Intestinal Tract: Influence of Structure, Rheology, and Mucoadhesion on the Intestinal Uptake in Rats.

Oral hyaluronic acid (HA) is a ubiquitous biopolymer that has gained attention as a treatment for local or systemic diseases. Here, we prepared and characterized structures of free HA (f-HA) with a high (>105 Da), intermediate (≤105 Da), and low (≤104 Da) average molar mass (MM); nanoparticles crosslinked with adipic dihydrazide (n-HA); and mixed formulations (mixed-HA) containing f-HA and n-HA. MM distribution determined the structure, hydrodynamic diameter, and zeta potential of the f-HAs. Crosslinking changed the physicochemical properties in n-HA. In vitro tack adhesion assays, using mucin tablets or a viable rat intestinal mucosa, showed better mucoadhesion with f-HA (intermediate MM) and mixed-HA (25% n-HA), especially in the jejunum segment. High MM f-HA presented negligible mucoadhesion. n-HA showed the deepest diffusion into the porous of the membranes. In vivo results showed that, except for high MM f-HA, there is an inverse relationship between rheological changes in the intestinal membrane macerates resulting from mucoadhesion and the effective intestinal permeability that led to blood clearance of the structures. We conclude that the n-HA formulations are promising for targeting other tissues, while formulations of f-HA (intermediate MM) and mixed-HA are better for treating dysbiosis.

Investigation on Intestinal Proteins and Drug Metabolizing Enzymes in Simulated Microgravity Rats by a Proteomics Method.

The present study aimed to investigate the change of intestinal mucosa proteins, especially the alteration of intestinal drug metabolizing enzymes (IDMEs) following 14-day simulated microgravity. Morey–Holton tail-suspension analog was used to simulate microgravity. Intestinal mucosa proteins of rats were determined by label-free quantitative proteomic strategy. A total of 335 differentially expressed proteins (DEPs) were identified, 190 DEPs were upregulated, and 145 DEPs were downregulated. According to bioinformatic analysis, most of DEPs exhibited hydrolase, oxidoreductase, transferase, ligase, or lyase catalytic activity. DEPs were mainly enriched in metabolic pathways, including metabolism of amino acid, glucose, and carbon. Moreover, 11 of DEPs were involved in exogenous drug and xenobiotics metabolism. Owing to the importance of IDMEs for the efficacy and safety of oral drugs, the expression of cytochrome P450 1A2 (CYP1A2), CYP2D1, CYP3A2, CYP2E1, alcohol dehydrogenase 1 (ADH1), and glutathione S-transferase mu 5 (GSTM5) in rat intestine mucosa was determined by Western-blot. The activity of ADH, aldehyde dehydrogenase (ALDH) and GST was evaluated. Compared with control rats, the expression of CYP1A2, CYP2D1, CYP3A2, and ADH1 in the simulated microgravity (SMG) group of rats were dramatically decreased by 33.16%, 21.93%, 48.49%, and 22.83%, respectively. GSTM5 was significantly upregulated by 53.14% and CYP2E1 expression did not show a dramatical change in SMG group rats. Moreover, 14-day SMG reduced ADH activity, while ALDH and GST activities was not altered remarkably. It could be concluded that SMG dramatically affected the expression and activity of some IDMEs, which might alter the efficacy or safety of their substrate drugs under microgravity. The present study provided some preliminary information on IDMEs under microgravity. It revealed the potential effect of SMG on intestinal metabolism, which may be helpful to understand the intestinal health of astronauts and medication use.

Salcaprozate sodium (SNAC) enhances permeability of octreotide across isolated rat and human intestinal epithelial mucosae in Ussing chambers

Octreotide is approved as a one-month injectable for treatment of acromegaly and neuroendocrine tumours. Oral delivery of the octapeptide is a challenge due mainly to low intestinal epithelial permeability. The intestinal permeation enhancer (PE) salcaprozate sodium (SNAC) has Generally Regarded As Safe (GRAS) status and is a component of an approved oral peptide formulation. The purpose of the study was to examine the capacity of salcaprozate sodium (SNAC), to increase its permeability across isolated rat intestinal mucosae from five regions and across human colonic mucosae mounted in Ussing chambers. Apical-side buffers were Kreb's-Henseleit (KH), fasted simulated intestinal fluid (FaSSIF-V2), rat simulated intestinal fluid (rSIF), and colonic simulated intestinal fluid (FaSSCoF). The basal apparent permeability coefficient (Papp) of [3H]-octreotide was equally low across rat intestinal regional mucosae in KH, rSIF, and FaSSIF-V2. Apical addition of 20 mM SNAC increased the Papp across rat tissue in KH: colon (by 3.2-fold) > ileum (3.4-fold) > upper jejunum (2.3-fold) > duodenum (1.4-fold) > stomach (1.4-fold). 20 mM and 40 mM SNAC also increased the Papp by 1.5-fold and 2.1-fold respectively across human colonic mucosae in KH. Transepithelial electrical resistance (TEER) values were reduced in the presence in SNAC especially in colonic regions. LC-MS/MS analysis of permeated unlabelled octreotide across human colonic mucosae in the presence of SNAC indicated that [3H]-octreotide remained intact. No gross damage was caused to rat or human mucosae by SNAC. Attenuation of the effects of SNAC was seen in rat jejunal mucosae incubated with FaSSIF-V2 and rSIF, and also to some extent in human colonic mucosae using FaSSCoF, suggesting interaction between SNAC with buffer components. In conclusion, SNAC showed potential as an intestinal permeation enhancer for octreotide, but in vivo efficacy may be attenuated by interactions with GI luminal fluid contents.

Comparison Between Conventional and Supersaturable Self-nanoemulsion Loaded with Nebivolol: Preparation and In-vitro/Ex-vivo Evaluation

Nebivolol (NBH) is a third-generation B1-blocker with high selectivity and vasodilation activity. Nevertheless, nebivolol exhibits low oral bioavailability, which may adversely affect its efficacy. Recently, supersaturable self-nanoemulsion (Su-SNE) is an advanced SNE approach that can address low bioavailability The study aims to prepare nebivolol-loaded Su-SNE by reduction the amount of the prepared conventional SNE to half. Besides, an appropriate polymer type and concentration to prevent NBH precipitation upon oral administration have investigated.. A conventional self-nanoemulsion (formula A) was prepared by dissolving NBH in 500 mg vehicle mixture of imwitor®988: cremophor-EL: propylene glycol. Then, eight Su-SNE formulas with the absence or presence of four different polymers were prepared and evaluated. In-vitro precipitation assay was performed to assess the precipitation inhibition capacity of polymers. The ex-vivo permeation through rat intestinal mucosa was also conducted for determination of permeability parameters. Results revealed that (Su-SNA formula SAS1) containing 5% soluplus could effectively retard the nebivolol precipitation. There was no statistical difference between formula A and SAS1; both maintained a higher apparent NBH concentra­tion for approximately 240 min in 0.1N HCl. The permeation rate of conventional (formula A) and soluplus-based Su-SNE (formula SAS1) was significantly improved, and the permeation enhancement ratio was found 2.7 and 3.2, respectively, as compared with non-formulated NBH. Consequently, it is concluded that developing soluplus-based nebivolol SNE is a promising alternative approach. It can enhance nebivolol stability and permeability with half the amount of conventional SNE components.

Bactericidal activity of transendothelial neutrophils based the endothelial IL-1α crosstalk during neutrophil–endothelial interaction

Abstract Neutrophils across endothelial cells to capture and eliminate bacterial pathogens is served as a vocation to prevent infectious diseases during innate immune. However, the mechanisms behind neutrophil-endothelial interaction on the bacterial elimination remains unclear. In this study, we employed a transwell system to co-culture rat intestinal mucosa microvascular endothelial cells (RIMVECs) and neutrophils to illustrate the killing mechanisms of transendothelial neutrophils. We discovered that endothelial interleukin-1α (IL-1α) promoted the survival of rats under Escherichia coli infection. IL-1α enhanced the bactericidal activity of transendothelial neutrophils, while the release of IL-1α is inhibited by lipopolysaccharide (LPS) derived from E. coli during infectious process. In addition, LPS majority damaged RIMVECs on cell membrane and induced cell necrosis. LPS promoted E. coli to escape from neutrophils in vivo and in vitro. Though the isobaric tags for relative and absolute quantification (iTRAQ) method to identify differentially expressed proteins of RIMVECs, we found that IL-1α modulates RIMVECs occurred on the plasma membrane, endoplasmic reticulum and mitochondrial envelope. There were eleven common proteins to persist regulatory. 2 h treatment of IL-1α triggered the cell adhesion molecules (CAMs) of RIMVECs, while oxidative phosphorylation was required for long times’ incubation of IL-1α (4 and 8 h). Our work highlights the critical role of endothelial IL-1α during neutrophil- endothelial interaction, which offered new targets in the bactericidal activity of neutrophils.

Discussion on the curative effect and mechanisms of berberine in rats with non-alcoholic fatty liver

Objective: To observe the curative effects of berberine in rats with high-fat diet induced non-alcoholic fatty liver and to further explore its possible mechanism. Methods: Twenty-six Sprague-Dawley rats (120-160 g) were randomly divided into 3 groups: control group (n = 8), model group (n = 10) and treatment group (n = 8). Rats in the control group were fed with regular diet, and the model group and the treatment group were fed a high-fat diet. At the 12th week, two rats in the in the model group were sacrificed to verify whether model was successful established. Subsequently, treatment group rats were given a gavage of berberine at a dose of 150 mg·kg(-1)·d(-1) for 4 weeks, and the control and the model group rats were given the same dose of normal saline. Rats were sacrificed at week 16th. HE staining was used to observe the changes in the intestinal mucosa of rats. Sudan black B staining was used to observe the fatty changes in liver. Immunohistochemical staining was used to observe the expression level of occludin protein in the intestinal epithelium. A real-time 16S rDNA PCR method was used to measure the number of escherichia coli, bacteroides and faecalibacterium prausnitzii in the feces of rats. Results: Model group had a higher serum levels of endotoxin (0.288 ± 0.045) and tumor necrosis factor (TNF)-α (1.07 ± 0.11) than the control group (0.192 ± 0.049, 0.94 ± 0.07) (P < 0.05). Berberine intervention had significantly reduced endotoxin (0.213 ± 0.025) and TNF-α level (0.93 ± 0.07) (P < 0.05). The expression level of occludin protein was significantly lower in the intestinal mucosa of model group than that of control group (0.166 ± 0.014), and berberine had promoted the expression of occludin protein in intestinal mucosa (0.055 ± 0.009), but the difference was not statistically significant (P > 0.05). At the same time, compared with the model group (7.29 ± 0.47), the number of bacteroidetes in the control group (9.49 ± 0.59) was decreased, while the number of bacteroidetes in the treatment group was increased (9.77 ± 0.87). The number of escherichia coli (6.92 ± 0.77) and faecalibacterium prausnitzii (8.70 ± 0.62) in the model group were increased than control group (5.42 ± 0.63, 9.49 ± 0.59), while the number of escherichia coli (6.34 ± 0.71) and faecalibacterium prausnitzii (9.77 ± 0.87) (P < 0.05) was reduced with the intervention of berberine. Conclusion: Berberine could effectively protect the intestinal barrier function in rats with NAFLD and the possible mechanism of action behind it may be the regulation of intestinal flora.

About the impact of superassociation of hydrophobic ion pairs on membrane permeability

AimThe study was aimed to investigate the impact of superassociation of hydrophobic ion pairs (HIPs) on membrane permeability. MethodsToluidine blue O (TBO) as a cationic model compound was complexed with anionic counter ions having different physiochemical properties namely dodecanoate (DD), oleate (OL), deoxycholate (DC), docusate (DO) and dodecyl sulfate (DS). TBO HIPs were characterized regarding log P, zeta potential and stability over 8 h at pH 7.4. Association and dissociation constants (Ka and Kd) were calculated by applying quasi-equilibrium equation to the double reciprocal plots of log P versus counter ion concentrations. Permeation studies of free TBO, superassociated TBO HIPs and HIPs applied as entirely dissociated form were carried out across human colorectal adenocarcinoma-derived cell line (Caco-2) and freshly excised rat intestinal mucosa. ResultsTBO HIPs of increasing lipophilicity ranging from log P 0.59 to 2.35 were obtained as a result of ion pairing with anionic counter ions. Zeta potential of TBO shifted from positive to negative due to ion pairing. HIPs with DO and DS showed highest stability at pH 7.4. Association constant (Ka) values for TBO HIPs were found in the following rank order; DS > DO > OL > DC > DD. Due to superassociation of HIPs, permeation of TBO was efficiently improved up to 3.1-fold across Caco-2 cells and up to 2.5-fold across rat intestinal mucosa. ConclusionSuperassociated HIPs showed generally a significantly higher membrane permeability than free TBO and entirely dissociated HIPs.

A novel rat model of inflammatory bowel disease developed using a device created with a 3D printer.

ObjectiveInflammatory bowel disease (IBD) is an intractable condition. Existing models of experimental IBD are limited by their inability to create consistent ulcers between animals. The aim of this study was to develop a novel model of experimental colitis with ulcers of reproducible size.DesignWe used a 3D printer to fabricate a novel device containing a small window (10 × 10 mm) that could be inserted rectally to facilitate the creation of a localized ulcer in the rat intestinal mucosa. The mucosa within the window of the device was exposed to 2,4,6-trinitrobenzene sulfonic acid (TNBS) to generate ulceration. We evaluated the effects of conventional drug therapies (mesalazine and prednisolone) and local transplantation of allogeneic adipose-derived mesenchymal stem cells (ASCs) on ulcer size (measured from photographic images using image analysis software) and degree of inflammation (assessed histologically).ResultsThe novel method produced localized, circular or elliptical ulcers that were highly reproducible in terms of size and depth. The pathological characteristics of the lesions were similar to those reported previously for conventional models of TNBS-induced colitis that show greater variation in ulcer size. Ulcer area was significantly reduced by the administration of mesalazine or prednisolone as an enema or localized injection of ASCs.ConclusionThe new model of TNBS-induced colitis, made with the aid of a device fabricated by 3D printing, generated ulcers that were reproducible in size. We anticipate that our new model of colitis will provide more reliable measures of treatment effects and prove useful in future studies of IBD therapies.

Tryptophan promoted β-defensin-2 expression via the mTOR pathway and its metabolites: kynurenine banding to aryl hydrocarbon receptor in rat intestine.

In this study, we investigated the signalling pathways mediating tryptophan (Trp)-promoted β-defensin-2 (BD-2) expression in rat intestinal mucosa. Sprague Dawley rats were administered with l-Trp and treated with rapamycin (RAPA), 1-methyltryptophan (1-MT), or para-chlorophenyl-amine (PCPA) to inhibit mammalian target of rapamycin (mTOR), indoleamine-2,3-dioxygenase (IDO), or tryptophan hydroxylase (TPH), respectively. The mRNA and protein levels of BD-2 in the jejunal and ileal mucosa of rats increased with administration of l-Trp. Intraperitoneal injection of RAPA significantly decreased the mRNA level of BD-2 and the concentrations of p-mTORC1 and BD-2 in the jejunal and ileal mucosa of rats with administration of l-Trp (P < 0.05). Oral administration of 1-MT decreased the IDO activity and the mRNA and protein levels of BD-2, and increased the concentrations of tumour necrosis factor (TNF-α), interleukin (IL)-17, and IL-22 in the jejunal and ileal mucosa of rats with administration of l-Trp (P < 0.05). Intraperitoneal injection of PCPA decreased the TPH activity and increased the mRNA and protein levels of BD-2, but did not change the concentrations of TNF-α, IL-17, or IL-22 in the jejunal and ileal mucosa of rats with administration of l-Trp. The results indicate the Trp-promoted BD-2 expression in the jejunum and ileum via the mTOR pathway and its metabolites: kynurenine banding to aryl hydrocarbon receptor in rat intestine.

Protective effect of hyperbaric oxygen treatment on rat intestinal mucosa after mesenteric ischaemia and reperfusion.

Mesenteric ischaemia results from a lack of adequate blood flow to and oxygenation of the mesentery and intestines. The aim of the present study was to evaluate the effect of hyperbaric oxygen treatment (HBOT) on the healing process in intestinal mucosa of rats undergoing mesenteric ischaemia and reperfusion. Thirty-two Wistar-Albino rats were divided into four groups of eight: 1) ischaemia/reperfusion (I/R); 2) sham operation; 3) I/R+HBOT started 6 hours after reperfusion; 4) I/R+HBOT started 12 hours after reperfusion. In the I/R groups, a vascular clamp was placed across the superior mesenteric artery to occlude arterial circulation for 60 minutes, followed by reperfusion. A dose of HBOT consisted of 100% oxygen breathing for 90 minutes at 2.5 atmospheres absolute pressure. Thirteen doses of HBOT were administered after ischaemia. The rats were sacrificed on the eighth day, and their intestinal tissues were harvested for histopathologic analysis. The tissue levels of catalase, malondialdehyde, and glutathione were determined. The histopathological scores (HSCORE) were consistent with macroscopic examinations. The scores were significantly higher (worse) in Group 1 compared to Group 2, Group 3, and Group 4 (for all comparisons, P < 0.05). Group 4's HSCORE was significantly higher than those of Group 2 and Group 3 (for both comparisons P < 0.05). Group 3's HSCOREs were only marginally higher than Group 2. Group 3 exhibited higher glutathione levels than Group 1 (P < 0.05). There were no significant differences across the groups with respect to malondialdehyde and catalase levels. A beneficial effect of HBOT was observed on oxidative stress and inflammation in acute mesenteric ischaemia-reperfusion.

Hydrophobic H-bond pairing: A novel approach to improve membrane permeability.

The aim of the present study was to develop hydrophobic H-bond pairs (HHPs) of leuprolide (LEU) with non-ionic surfactants to improve its membrane permeability. LEU was lipidized via hydrophobic H-bond pairing (HHP) with the sucrose esters (SEs) sucrose laurate HLB 15 (SLA-15), sucrose palmitate HLB 16 (SPA-16), sucrose stearate HLB 11 (SST-11) and sucrose stearate HLB 15 (SST-15). HHPs were evaluated regarding precipitation efficiency in water, zeta potential, log Pn-octanol/water and dissociation behavior at various pH over time. Cytotoxic potential of HHPs of LEU with SST-11 was investigated on Caco-2 cells. Subsequently, ex vivo permeation studies were carried out across freshly excised Sprague-Dawley rat intestinal mucosa. At a molar ratio of LEU to SEs of 1:≥1 a precipitation efficiency of above 50% was achieved. Zeta potential of complexes was neither influenced by the type nor the amount of added surfactants. Log Pn-octanol/water of LEU was up to 250-fold increased due to HHP utilizing SST-11. Dissociation studies showed that HHPs of LEU with SST-11 dissociate up to 20% in gastrointestinal (GI) pH conditions within 4h. Moreover, HHPs of LEU with SST-11 exhibited no cytotoxicity. Ex vivo permeation studies revealed 2-fold improved membrane permeation of HHPs of LEU with SST-11 compared to free LEU. Findings of this study show that HHP can be considered as a promising strategy to improve membrane permeation.

Antioxidant protection enzyme activity in the blood serum and large intestinal mucosa of rats with prolonged gastric hypochlorhydria and given multiprobiotics

The activity of antioxidant protection enzymes in the blood serum and colon mucosa in rats was studied under the conditions of 28-days administration of omeprazole on its own and omeprazole together with multiprobiotics "Symbiter" and "Apibact". Physiological and biochemical study methods were applied. It was found that after omeprazole administration, the activity of superoxide dismutase in the blood serum decreased, and the activity of catalase increased compared to the control. With the co-administration of omeprazole and multiprobiotics, the activity of superoxide dismutase increased compared to the group of rats that received omeprazole only during the same time, but remained less compared to the control group. The content of reduced glutathione in the blood serum of rats after administration of omeprazole decreased, the activity of glutathione peroxidase and glutathione transferase increased, and the activity of glutathione reductase decreased compared to the control. With co-administration of omeprazole and multiprobiotics, the serum RG content was at the control level, the activity of glutathione reductase exceeded the control values. The activity of glutathione reductase decreased compared to the group receiving omeprazole only. The activity of glutathione reductase increased and did not differ from the control values. In the colon mucosa, superoxide dismutase and catalase activity decreased compared to control. With the combined administration of omeprazole and multiprobiotics, superoxide dismutase and catalase activity increased and even exceeded the control values. With the administration of omeprazole, the reduced glutathione content in the colon mucosa was lower than that in the control. The activity of glutathione peroxidase increased and glutathione transferase and activity of glutathione reductase decreased compared to the control. With co-administration of omeprazole and multiprobiotics to rats, the reduced glutathione content increased compared to the group of rats administered omeprazole only, and even exceeded that in the control.

Evaluation of Sucrose Laurate as an Intestinal Permeation Enhancer for Macromolecules: Ex Vivo and In Vivo Studies.

Oral delivery of macromolecules requires permeation enhancers (PEs) adaptable to formulation. Sucrose laurate (SL) (D1216), a food grade surfactant, was assessed in Caco-2 monolayers, isolated rat intestinal tissue mucosae, and rat intestinal instillations. Accordingly, 1 mM SL increased the apparent permeability coefficient (Papp) of [14C]-mannitol and reduced transepithelial electrical resistance (TEER) across monolayers. It altered expression of the tight junction protein, ZO-1, increased plasma membrane potential, and decreased mitochondrial membrane potential in Caco-2 cells. The concentrations that increased flux were of the same order as those that induced cytotoxicity. In rat colonic tissue mucosae, the same patterns emerged in respect to the concentration-dependent increases in paracellular marker fluxes and TEER reductions with 5 mM being the key concentration. While the histology revealed some perturbation, ion transport capacity was retained. In rat jejunal and colonic instillations, 50 and 100 mM SL co-administered with insulin induced blood glucose reductions and achieved relative bioavailability values of 2.4% and 8.9%, respectively, on a par with the gold standard PE, sodium caprate (C10). The histology of the intestinal loops revealed little damage. In conclusion, SL is a candidate PE with high potential for emulsion-based systems. The primary action is plasma membrane perturbation, leading to tight junction openings and a predominant paracellular flux.

Effects of Macronutrients on the In Vitro Production of ClpB, a Bacterial Mimetic Protein of α-MSH and Its Possible Role in Satiety Signaling

Gut microbiota can influence the feeding behavior of the host, but the underlying mechanisms are unknown. Recently, caseinolytic protease B (ClpB), a disaggregation chaperon protein of Escherichia coli, was identified as a conformational mimetic of α-melanocyte-stimulating hormone (α-MSH), an anorexigenic neuropeptide. Importantly, ClpB was necessary for E. coli to have an anorexigenic effect in mice, suggesting that it may participate in satiety signaling. To explore this further, we determined the short-term (2 h) effects of three macronutrients: protein (bovine serum albumin), carbohydrate (D-fructose) and fat (oleic acid), on the production of ClpB by E. coli and analyzed whether ClpB can stimulate the secretion of the intestinal satiety hormone, peptide YY (PYY). Isocaloric amounts of all three macronutrients added to a continuous culture of E. coli increased ClpB immunoreactivity. However, to increase the levels of ClpB mRNA and ClpB protein in bacteria and supernatants, supplementation with protein was required. A nanomolar concentration of recombinant E. coli ClpB dose-dependently stimulated PYY secretion from the primary cell cultures of rat intestinal mucosa. Total proteins extracted from E. coli but not from ClpB-deficient E. coli strains also tended to increase PYY secretion. These data support a possible link between E. coli ClpB and protein-induced satiety signaling in the gut.

Propolis modulates the gut microbiota and improves the intestinal mucosal barrier function in diabetic rats

Objective: Diabetes mellitus is associated with gut microbiota disturbance and intestinal mucosal injuries. This study investigated the influence of propolis on the gut microbiota and intestinal mucosa in rats with diabetes. Methods: Sprague-Dawley (SD) rats were randomly assigned to the control group, model group, and three propolis groups (supplemented with 80, 160, and 240 mg/kg·bw propolis, respectively). A high-fat diet combined with a streptozotocin (STZ) abdominal injection were used to induce diabetes in the rats. After 4 weeks, the intestinal histopathological analysis of the ileum was observed by transmission electron microscopy. The fasting blood glucose (FBG), plasma insulin, glucose tolerance (OGTT) and glycosylated hemoglobin (HbA1c) levels were measured. The expression of tight junction (TJ) proteins in the ileum was measured using western blotting. The molecular ecology of the fecal gut microbiota was analyzed by 16S rDNA high-throughput sequencing. The contents of the short-chain fatty acids (SCFAs) in feces were measured using high-performance liquid chromatography (HPLC). Results: After propolis treatment, compared to the model group, FBG and HbA1c levels declined, while the glucose tolerance and insulin sensitivity index (ISI) increased. The levels of TJ proteins in the ileum increased in the propolis groups. The tight junctions and gap junctions of the intestinal epithelium were also improved in the propolis groups. The contents of the feces acetic acid, propionic acid and butyrate were increased in the propolis groups. 16S rDNA high-throughput sequencing revealed that the composition of the gut microbiota of rats in the propolis supplement group was significantly improved. Conclusions: Compared to the model group, propolis exerted hypoglycemic effects in diabetic rats, and it repaired intestinal mucosal damage, benefited the communities of the gut microbiota and increased SCFA levels in diabetic rats.

Mucoadhesive paclitaxel-loaded chitosan-poly (isobutyl cyanoacrylate) core-shell nanocapsules containing copaiba oil designed for oral drug delivery

The development of drug delivery systems for potent anticancer drugs like paclitaxel remains a challenger. The aim of this work was to study the mucoadhesive properties of paclitaxel-loaded chitosan-poly (isobutyl cyanoacrylate) core-shell nanocapsules designed for oral drug delivery. Using an experimental design approach, the nanocapsules were produced and, then, physicochemically characterized. Mucoadhesion assays were performed in-vitro by the aggregation test with mucin and ex-vivo, in Ussing Chamber, using freshly excised rat intestinal mucosa. [3H]-paclitaxel dosages were carried out by liquid scintillation. Paclitaxel-loaded nanocapsules showed a mean hydrodynamic diameter of 470 nm with low polydispersity index and spherical form. Encapsulation efficiency and drug loading of paclitaxel were 74 ± 1% and 1.70 ± 0.02%, respectively. After drying, nanocapsules could be redispersed with no changes on their nanostructure. Dispersions of nanocapsules were stable in simulated gastric medium for 120 min, and after six months of storage at 4 °C. They showed interesting mucoadhesive properties with mucins and good association (9%) with the intestinal mucosa of the rat. Taking together, results from the present work are encouraging to pursue the development of chitosan-coated nanocapsules for oral delivery of paclitaxel as a new treatment for cancer with possible synergetic anticancer effect with the therapeutically active components found in copaiba oil.

Injury of small intestinal mucosa in rats induced by aspirin and clopidogrel and the protective effect of teprenone

The purpose of this study was to investigate the injury of aspirin and clopidogrel on small intestinal mucosa in rats and the protective effect of teprenone. The study found that aspirin and clopidogrel could cause intestinal mucosal injury in rats, which was even worse with dual drugs. The mechanism of mucosal injury included free radical injury induced by aspirin and decreased synthesis of vascular endothelial growth factor (VEGF) by clopidogrel. Teprenone may repair intestinal mucosa via boosting VEGF level.