Intestinal Strips Research Articles

Fucoidan improves intestinal peristaltic function in rats with postoperative ileus.

The effect of fucoidan on postoperative ileus (POI) has not been studied. In this study, how fucoidan ameliorates POI in a rat POI model was investigated. The results showed that in the model animals, when the first defecation time was prolonged, the amount of food consumed decreased, the small intestinal propulsion rate dramatically slowed, and the motility index (MI%) of the small intestine decreased. In vitro experiments revealed that the contractile response of small intestinal smooth muscle strips to carbachol (CCh) was reduced. Immunohistochemistry revealed evident macrophage infiltration in the intestinal muscularis. However, after oral pretreatment with fucoidan, the time to first defecation decreased, and food intake, the small intestinal propulsion rate, and MI% of the small intestine increased. Additionally, the contractile response of the intestinal strips to CCh became stronger, and macrophage infiltration decreased. Mechanistically, fucoidan alleviated POI by exerting anti-inflammatory and antioxidant effects as well as likely through the TrkB/ERK1/2/Akt signalling pathways. When POI occurred, the expression levels of inflammatory factors in the intestines significantly increased while the phosphorylation of TrkB, ERK1/2, and Akt significantly decreased; malondialdehyde (MDA) levels in the intestines increased but the levels of superoxide dismutase (SOD) and glutathione (GSH) decreased. In contrast, after pretreatment with fucoidan, the expression levels of inflammatory factors decreased; the phosphorylation levels of TrkB, ERK1/2, and Akt increased; the MDA level decreased; and SOD and GSH levels increased. Thus, fucoidan alleviated POI-induced impairment of rat intestinal motility through anti-inflammatory and antioxidant effects possibly associated with the TrkB/ERK1/2 and Akt signalling pathways.

The dual effects of dexmedetomidine on intestinal barrier and intestinal motility during sepsis

BackgroundSepsis, characterized by dysregulated host responses to infection, remains a critical global health concern, with high morbidity and mortality rates. The gastrointestinal tract assumes a pivotal role in sepsis due to its dual functionality as a protective barrier against injurious agents and as a regulator of motility. Dexmedetomidine, an α2-adrenergic agonist commonly employed in critical care settings, exhibits promise in influencing the maintenance of intestinal barrier integrity during sepsis. However, its impact on intestinal motility, a crucial component of intestinal function, remains incompletely understood. MethodsIn this study, we investigated dexmedetomidine’s multifaceted effects on intestinal barrier function and motility during sepsis using both in vitro and in vivo models. Sepsis was induced in Sprague-Dawley rats via cecal ligation and puncture. Rats were treated with dexmedetomidine post-cecal ligation and puncture, and various parameters were assessed to elucidate dexmedetomidine's impact. ResultsOur findings revealed a dichotomous influence of dexmedetomidine on intestinal physiology. In septic rats, dexmedetomidine administration resulted in improved intestinal barrier integrity, as evidenced by reduced mucosal hyper-permeability and morphological alterations. However, a contrasting effect was observed on intestinal motility, as dexmedetomidine treatment inhibited both the frequency and amplitude of contractions in isolated intestinal strips and decreased the distance of ink migration in vivo. Additionally, dexmedetomidine suppressed the secretion of pro-motility hormones while having no influence on hormones that inhibit intestinal peristalsis. ConclusionThe study revealed that during sepsis, dexmedetomidine exhibited protective effects on barrier integrity, although concurrently it hindered intestinal motility, partly attributed to its modulation of pro-motility hormone secretion. These findings underscore the necessity of a comprehensive understanding of dexmedetomidine’s impact on multiple facets of gastrointestinal physiology in sepsis management, offering potential implications for therapeutic strategies and patient care.

Protective effects of Moringa oleifera against acetic acid-induced colitis in rat: Inflammatory mediators’ inhibition and preservation the colon morphohistology

Moringa oleifera decoction is used in folk medicine to alleviate various gastrointestinal ailments and has been shown in several studies to exhibit diverse biological activities: antioxidant, anti-inflammatory, and myorelaxant on intestine strips. However, its protective effect on pro-inflammatory cytokines in colitis remains to be ascertained. We investigated Moringa oleifera leaf aqueous extract activities on a rat model of acetic acid-induced colitis. Thirty-six rats were divided in random into six groups, and received either distilled water (10 mL/kg), the aqueous leaf extract of Moringa oleifera (25, 50, and 100 mg/kg) or the reference drug Loperamide (5 mg/kg) for 20 days. Animal body weight and food intake were followed-up. Colitis was induced on day 15, and daily stool weight was followed up. Animals were sacrificed (day 21), serum concentrations of pro-inflammatory cytokines MPO, IL-6, and TNF-α were evaluated, and the colon and liver preserved for histological examinations. After one-week pre-treatment, a significant (P < 0.05) weight increase was observed. At day 20, the extract significantly (P < 0.01) prevented weight loss. Food intake decreased by 36.33% in the colitis control, and by 4.34% in the extract (100 mg/kg) treated animals (P < 0.01). Moringa oleifera (100 mg/kg, day 20) decreased stool weights to 4.75±0.3 g (P < 0.05). The extract decreased (P < 0.01) MPO level. At 100 mg/kg, it significantly (P < 0.05) reduced IL-6 –0.58 ± 0.14 against 0.85 ± 0.00 ng/L in the colitis control. At the same dose, TNF-α levels decreased to 417.96 ± 0.17 ng/L (P < 0.001). Moringa oleifera alleviated colitis symptoms by reducing stool emission, alleviating inflammation, and preserving colon and liver cytoarchitecture.

Microcystin-LR sensitizes the Oncorhynchus mykiss intestinal epithelium and interacts with paralytic shellfish toxins to alter oxidative balance

In the context of harmful algal blooms, fish can be exposed to the combined effects of more than one toxin. We studied the effects of consecutive exposure to Microcystin-LR (MCLR) in vivo and paralytic shellfish toxins (PST) ex vivo/in vitro (MCLR+PST) in the rainbow trout Oncorhynchus mykiss's middle intestine. We fed juvenile fish with MCLR incorporated in the feed every 12 h and euthanized them 48 h after the first feeding. Immediately, we removed the middle intestine to make ex vivo and in vitro preparations and exposed them to PST for one hour. We analyzed glutathione (GSH) and glutathione disulfide (GSSG) contents, glutathione S-transferase (GST), glutathione reductase (GR), catalase (CAT), and protein phosphatase 1 (PP1) activities in ex vivo intestinal strips; apical and basolateral ATP-biding cassette subfamily C (Abcc)-mediated transport in ex vivo everted and non- everted sacs; and reactive oxygen species (ROS) production in isolated enterocytes in vitro. MCLR+PST treatment decreased the GSH content, GSH/GSSG ratio, GST activity, and increased ROS production. GR activity remained unchanged, while CAT activity only increased in response to PST. MCLR inhibited PP1 activity and activated Abcc-mediated transport only at the basolateral side of the intestine. Our results show a combined effect of MCLR+PST on the oxidative balance in the O. mykiss middle intestine, which is not affected by the two toxins groups when applied individually. Basolateral Abcc transporters activation by MCLR treatment could lead to an increase in the absorption of toxicants (including MCLR) into the organism. Therefore, MCLR makes the O. mykiss middle intestine more sensitive to possibly co-occurring cyanotoxins like PST.

Пригнічувальна дія загального анестетика кетаміну на транзієнти внутрішньоклітинної концентрації іонів кальцію та скорочення гладеньком’язових клітин тонкої кишки миші

The mechanisms of the negative consequences of general anaesthetics action on the nervous system have been studied in detail, but regarding smooth muscle function, such issues have not yet been sufficiently addressed. In this study, we investigated the effect of the general intravenous anaesthetic ketamine on the level of intracellular calcium in isolated ileum myocytes and the contractile activity of smooth muscle strips of the mouse small intestine. The concentration of intracellular calcium in cells was measured using the Ca2+-sensitive fluorescent dye Fura-2, and tensiometry was used to record the contractile activity of smooth muscles. It was shown that ketamine at a concentration of 100 µM significantly, by 40%, suppressed carbachol-induced contractile reactions of the ileum. The inhibitory effect correlated with the suppression of the intracellular calcium responses to carbachol in isolated smooth muscle cells after the addition of ketamine to the extracellular solution, which was by 65% on average. These results contribute to our better understanding of the possible membrane and intracellular mechanisms of the development of post-surgical intestinal motility disorders.

Chitosan adhesives with sub-micron structures for photochemical tissue bonding

We describe a method for fabricating biocompatible chitosan-based adhesives with sub-micron structures to enhance tissue bonding. This procedure avoids coating and chemical modification of structures and requires a simple drop-casting step for the adhesive film formation. Chitosan thin films (27±3 μm) were fabricated with sub-micron pillars (rectangular cuboid with height ∼150 nm, square dimension ∼1 μm and pitch ∼2 μm) or holes (diameter ~500 nm or ~1 μm, depth ~100 or 400 nm, pitch of 1 or 2 μm). Polydimethylsiloxane moulds were used as negative templates for the adhesive solution that was cast and then allowed to dry to form thin films. These were applied on bisected rectangular strips of small sheep intestine and photochemically bonded by a green laser (λ= 532 nm, irradiance ∼110 J/cm2). The tissue repair was subsequently measured using a computer-interfaced tensiometer. The mould sub-micron structures were reproduced in the chitosan adhesive with high fidelity. The adhesive with pillars achieved the highest bonding strength (17.1±1.2 kPa) when compared to the adhesive with holes (13.0±1.3 kPa, p&lt;0.0001, one-way ANOVA, n=15). The production of chitosan films with patterned pillars or holes in the sub-micron range was demonstrated, using a polydimethylsiloxane mould and a single drop-casting step. This technique is potentially scalable to produce adhesives of larger surface areas.

Microcystin-LR modulates multixenobiotic resistance proteins in the middle intestine of rainbow trout, Oncorhynchus mykiss.

Global climate change favors explosive population growth events (blooms) of phytoplanktonic species, often producing toxic products, e.g., several genera of cyanobacteria synthesize a family of cyanotoxins called microcystins (MCs). Freshwater fish such as the rainbow trout Oncorhynchus mykiss can uptake MCs accumulated in the food chain. We studied the toxic effects and modulation of the activity and expression of multixenobiotic resistance proteins (ABCC transporters and the enzyme glutathione S-transferase (GST) in the O. mykiss middle intestine by microcystin-LR (MCLR). Juvenile fish were fed with MCLR incorporated in the food every 12 h and euthanized at 12, 24, or 48 h. We estimated the ABCC-mediated transport in ex vivo intestinal strips to estimate ABCC-mediated transport activity. We measured total and reduced (GSH) glutathione contents and GST and glutathione reductase (GR) activities. We studied MCLR cytotoxicity by measuring protein phosphatase 1 (PP1) activity and lysosomal membrane stability. Finally, we examined the relationship between ROS production and lysosomal membrane stability through in vitro experiments. Dietary MCLR had a time-dependent effect on ABCC-mediated transport, from inhibition at 12 h to a significant increase after 48 h. GST activity decreased only at 12 h, and GR activity only increased at 48 h. There were no effects on GSH or total glutathione contents. MCLR inhibited PP1 activity and diminished the lysosomal membrane stability at the three experimental times. In the in vitro study, the lysosomal membrane stability decreased in a concentration-dependent fashion from 0 to 5 µmol L − 1 MCLR, while ROS production increased only at 5 µmol L − 1 MCLR. MCLR did not affect mRNA expression of abcc2 or gst-π. We conclude that MCLR modulates ABCC-mediated transport activity in O. mykiss's middle intestine in a time-dependent manner. The transport rate increase does not impair MCLR cytotoxic effects.

Motilin is a regulator of gastric contraction in Japanese fire belly newts (Cynops pyrrhogaster), in vitro studies using isolated gastrointestinal strips of newts, rabbits, and chickens

The effects of newt motilin on the contractility of the isolated gastrointestinal (GI) tract from Japanese fire belly newts (newt) were examined to clarify whether motilin regulates GI motility in urodele amphibians. In addition, contractile responsiveness to motilins from seven species of vertebrates (human, chicken, turtle, alligator, axolotol, newt and zebrafish) were compared in GI preparations from three different animals (rabbit duodenum, chicken ileum and newt stomach) to determine the species-specific action of motilin. Newt motilin (10-10 M – 10−6 M) caused a contraction of cognate gastric strips, while the upper, middle, and lower intestinal strips were insensitive. The rank order of motilins for contractile activity in newt gastric strips was newt > alligator > axolotol > chicken > turtle > human ≫ zebrafish. On the other hand, newt motilin caused a weak contraction in the rabbit duodenum (human > alligator = chicken > turtle > newt ≧ axolotol > zebrafish), and it was ineffective in the chicken ileum (chicken > turtle > alligator > human ≫ newt, axolotol and zebrafish). This study demonstrates that motilin induces contraction in the GI tract of a urodele amphibian, the newt, in a region (stomach)-specific manner and further indicates that a ligand-receptor interaction of the motilin system is a species-specific manner probably due to differences in the amino acid sequence of motilin.

Chlorpyrifos stimulates ABCC-mediated transport in the intestine of the rainbow trout Oncorhynchus mykiss

The organophosphorus pesticide chlorpyrifos, detected in water and food worldwide, has also been found in the Río Negro and Neuquén Valley, North Patagonia, Argentina, where the rainbow trout, Oncorhynchus mykiss, is one of the most abundant fish species. We analyzed whether chlorpyrifos affects the transport activity of the ATP-binding cassette protein transporters from the subfamily C (ABCC), which are critical components of multixenobiotic resistance.We exposed ex vivo O. mykiss middle intestine strips (non-polarized) and segments (polarized) for one hour to 0 (solvent control), 3, 10, and 20 μg L−1 and to 0, 10, and 20 μg L−1 chlorpyrifos, respectively. We estimated the Abcc-mediated transport rate by measuring the transport rate of the specific Abcc substrate 2,4-dinitrophenyl-S-glutathione (DNP-SG). In addition, we measured the enzymatic activity of cholinesterase, carboxylesterase, glutathione-S-transferase, and 7-ethoxyresorufin-O-deethylase (EROD, indicative of the activity of cytochrome P450 monooxygenase 1A, CYP1A). We also measured lipid peroxidation using the thiobarbituric acid reactive substances method and the gene expression of Abcc2 and genes of the AhR pathway, AhR, ARNT, and cyp1a, by qRT-PCR. Chlorpyrifos induced the DNP-SG transport rate in middle intestine strips in a concentration-dependent manner (49–71%). In polarized preparations, the induction of the DNP-SG transport rate was observed only in everted segments exposed to 20 μg L−1 chlorpyrifos (40%), indicating that CPF only stimulated the apical (luminal) transport flux. Exposure to chlorpyrifos increased GST activity by 42% in intestine strips and inhibited EROD activity (47.5%). In addition, chlorpyrifos exposure inhibited cholinesterase (34–55%) and carboxylesterase (33–42.5%) activities at all the concentrations assayed and increased TBARS levels in a concentration-dependent manner (71–123%). Exposure to 20 μgL−1 chlorpyrifos did not affect the mRNA expression of the studied genes. The lack of inhibition of DNP-SG transport suggests that chlorpyrifos is not an Abcc substrate. Instead, CPF induces the activity of Abcc proteins in the apical membrane of enterocytes, likely through a post-translational pathway.

Pathogenetic Features of Restoring of Urinary Reservoir Function, Which Was Replaced by an Ileum Implant (Experimental Study)

Bladder cancer accounts for 50–70% of all malignant diseases of genital urinary system and 4% of all oncological diseases. It is well known, that in Ukraine men have such pathology 4 times more often than women and, unfortunately, up to 22% of patients die within the first year after confirmed diagnosis. The basic criteria of treatment effectiveness of the patients with oncological diseases are not only the rate of their survival, but also their quality of life. One of the main types of treatment for muscle-invasive bladder cancer is radical cystectomy with different variants of urinary diversion. The morphological changes in the muscle layer of the neobladder can cause deviations in the regulations of its contractility. This evolution of the smooth muscle wall demonstrates the electrophysiological contractility features of the neobladder compared to the ileum. The objective: to analyze the pathogenetic moments of the smooth muscle contractility regulation of the artificial bladder. Materials and methods. The experimental study on female mini-pigs aged 16–19 months, with weight 30–40 kg, the duration of the study was 12 months. The experimental model of the artificial bladder was performed by cystectomy in animals following by the terminal ileum of the neocyst, its anastomosis with the ureters, urethra under the anesthesia. After the forming of the neobladder the experimental animals had anesthesia with tiopental, and the neocyst and part of the ileum were removed, in one year. The experiments were carried put on the 18 pairs of specimens: isolated strips of the small intestine of mini-pigs and strips of the wall of the artificial bladder. Results. It was determined that spontaneous activity of the ileum and neobladder smooth muscles in 12 months has different indices. During the experiment the spontaneous activities of longitudinal smooth muscles (SM) of the ileum and neobladder were compared. It was determined that the spontaneous contractions of the neobladder SM are significantly different from the strip ileum contraction in control by larger amplitude and the complex shape. Conclusions. The hypertrophic growth of smooth muscles (SM) is a complex dynamic phenomenon that includes not only the structural changes, but also the complex physiological processes, namely aimed at transforming the part of the intestines to perform a new function of the urinary reservoir. The artificial bladder performs the functions of the natural bladder, there by making the life easier for a patient. The study of smooth muscle contractive activity regulation mechanisms under the influence of nervous and humoral systems will allow to expand the methods of its correction.

The response of Vitamin D to the Motility of Isolated Intestines in Male Rats

Vitamin D exists in a variety of forms (vitamers). Vitamin D2 (ergocalciferol) and vitamin D3 are the two most common forms (calcitriol). VDRs (nutritional D receptors) are found in almost every tissue and cell. Gastrointestinal receptors are of therapeutic importance for the treatment of motility disorders. The present study was designed to demonstrate the modulatory effects of Vit.D on intestinal motility in adult male albino rats. Vitamin D was tested on intestinal strips with different intestinal receptor blockers (atropine sulfate, propranolol, verapamil, prazosin), followed by the addition of Vit.D on isolated intestinal strips. The obtained data demonstrated the optimal stimulatory effect of Ach on the isolated intestinal muscles for intestinal muscle contraction. Furthermore, the inhibitory effects of high-dose nicotine had no effect on the excitatory response. Therefore, it can be concluded that Vit.D has an effective stimulatory response on the isolated rat intestinal muscle.

Evaluation of spasmolytic effects of naringenin on ileum contraction and intestinal charcoal meal transit: Involvement of ATP-sensitive K+ channels

Introduction: Naringenin is a flavonoid constituent of many herbal plants, including citreous fruits. Biological studies have suggested various therapeutic effects for naringenin, including protective effects on gastrointestinal (GI) motility. The present study was performed to investigate the involvement of ATP-sensitive K+ channels on the effect of naringenin in rat ileum motility. Methods: Ileum contractions were induced by either KCl or acetylcholine (ACh) in vitro. Inhibitory concentration-response curves were constructed for naringenin and diazoxide after exposure of rat isolated ileum to KCl (20mM) or ACh (500nM). The relaxant effects of naringenin and diazoxide were also examined in the presence of glibenclamide. Furthermore, oral effects of diazoxide (25 mg/kg) and naringenin (25, 50 mg/kg) were also assessed on the intestinal charcoal meal transit in mice (n=10) in the absence and presence of glibenclamide (50 mg/kg). Results: Diazoxide and naringenin in a concentration-dependent manner inhibited ileum contractions induced by low bath concentration of KCl (20mM). However, both drugs had no effect on contractions induced by a high concentration of KCl (160mM). The inhibitory effects of diazoxide and naringenin were blocked by glibenclamide. Oral administration of diazoxide and naringenin significantly reduced the intestinal transit of charcoal meal. The delay in the intestinal transit was blocked by the oral dose of glibenclamide. The effect of naringenin on the rat intestinal strip pre-contracted with the KCl was relatively similar to that of ATP-sensitive K+ channel opener (diazoxide). Conclusion: This research supports that ATP-sensitive K+ channels are involved in the rat small intestinal smooth muscles relaxation induced by naringenin.

Histological evaluation of the intestine of broiler chickens: comparison of three sampling methods

After the growth-promoting antibiotics prohibition, intestinal health became an increasing concern worldwide in poultry farming. The intestinal histological evaluation is an inexpensive technique that brings relevant information, but in poultry, the immediate process of intestinal post-mortem autolysis interferes directly on the samples quality for histological analysis hindering a precise diagnosis. This study aimed to standardize a technique for broilers’ intestines sample collection and fixation for histological analysis. Seven broiler chickens received a standard diet until 23 days of age when they were euthanized. Fragments of duodenum, jejunum, and ileum were collected using three methods: intestine strips, transverse section, and Swiss roll and posteriorly fixed in 10% buffered formalin and bouin solution. Tissue samples were submitted for histological (number of villi and viable villi per field) and morphometrical (villi height, crypt depth and villi:crypt ratio) evaluations and the results analyzed statistically. A significant high number of villi and viable villi per field in all regions was observed in the Swiss roll method. In the duodenum (p= 0.0066) and jejunum (p= 0.0058) an interaction between the Swiss roll method and the fixative buffered formalin was observed in the viable and number of villi per field, respectively. Regarding the morphometrical analysis significant differences were observed, in the jejunum villi height sampling by the methods Swiss roll (1,157.66 ± 148.25 μm, p= 0.0015) that showed the highest mean. Deeper crypt depths were observed in the jejunum (156.59 ± 15.68 μm, p= 0.0002) and ileum (131.13 ± 15.01 μm, p= 0.0006) collect by the Swiss roll method. An interaction between the bouin fixative was also observed in the jejunum (p= 0.0223) for this variable. Duodenum sampling by transversal section (12.68 ± 1.45 μm, p= 0.0076) was the only segment that had a significant difference for villi:crypt ratio, showing the highest mean. It can be concluded that the Swiss roll technique was the best method for morphometrical evaluation of the chickens’ intestines, since the highest counts of villi per field and viable villi per field were obtained, while buffered formalin was considered as the best fixative.

Исследование всасывания глюкозы в тонкой кишке крыс на интегративных экспериментальных моделях

The search for adequate experimental models to study glucose absorption in the small intestine stands high on the research agenda for physiologists. The most substantial advancements in the study of glucose absorption mechanisms were reached by using various analytical (simplified) experimental models: from pieces and strips of the small intestine to isolated intestinal cells and membrane vesicles. At the same time, the main regularities of the processes occurring in the body, as well as their real scale, can be revealed only through various integrative experimental models. The article is a brief overview of the two versions of such integrative models: 1) perfusion of the isolated loop of the small intestine with glucose solutions in chronic experiment and, 2) evaluation of the absorptive capacity of the small intestine by the rate of free consumption of concentrated glucose solution by animals. The paper provides examples of applying the two experimental models to study the real rates of glucose absorption in the small intestine of rats under conditions close to natural physiological ones. The paper outlines the main methodological features of each approach, their advantages and limitations. The two experimental approaches complement each other and significantly expand the modern understanding of the real scale and mechanisms of glucose absorption regulation in the small intestine under normal physiological conditions.

Calcium-sensing receptor (CaSR) agonist R568 inhibits small intestinal motility of mice through neural and non-neural mechanisms.

Gastrointestinal motility (GI) disorder causes symptoms such as dyspepsia, abdominal distention, and constipation and severely affects quality of life. The calcium (Ca2+)-sensing receptor (CaSR) expressed in the digestive tract can be activated by amino acids and participates in GI motility regulation. This study is designed to explore the effect and underlying mechanism of CaSR agonist R568 on the small intestine motility of mice in vivo and ex vivo. R568 was given to male C57BL/6 mice by gavage or incubated with isolated jejunum and ileum segments to observe its effects on GI motility and the involved neurons, neurotransmitters and hormones were detected by fluorescence immunohistochemistry and enzyme-linked immunosorbent assays. The in vivo results showed that the intestinal propulsive rate reduced in response to oral intake of R568. R568 treatment increased the numbers of nitric oxide synthase-positive neurons and nitric oxide release but decreased the choline acetyl transferase-positive neurons and acetylcholine release in the myenteric plexuses. R568 increased the secretion of cholecystokinin in the intestinal tissues and serum but had no effect on the secretion of glucagon like peptide-1. Ex vivo results showed that R568 inhibited the contractility of intestinal strips from the jejunum and ileum. Nitric oxide synthase (NOS) inhibitor L-nitroarginine methyl ester (L-NAME), M-receptor antagonist-atropine, and tetrodotoxin (TTX) failed to block the effect of R568. CaSR co-expressed with interstitial cells of Cajal (ICCs) in the myenteric plexus suggests the possibility that ICCs mediated the effect of R568. Our findings demonstrate that CaSR activation inhibited intestinal motility, and both the enteric nervous system and non-neural mechanism are involved in this process.

Pharmacological screening of the phenolic compound caffeic acid using rat aorta, uterus and ileum smooth muscle

Caffeic acid is a phenolic compound widely found in commonly consumed foods such as pears, apples and coffee, and is pharmacologically known for its antioxidant, anti-inflammatory and anti-asthmatic properties. However, its relaxant activity in the aorta, uterus and ileum smooth muscle has not been investigated. This study aimed to comparatively evaluate the effect of caffeic acid on smooth muscle from different organs (aorta, uterus and ileum), and the contractions of this different organ were induced by different agonists. The organ bath technique was used, where the organs were placed in different cuvettes with 10 mL of Tyrode solution for 1 h to stabilize, then, myometrial, intestinal strip and aortic ring contractions were evoked using different contractile agonists (KCl 60 mM, PHE 0.1 μM, OT 10-2 IU/mL, CCh 10−6 M and BaCl2 0.1–30 mM); increasing concentrations of caffeic acid (0.03–7 mM) were administered in the experimental preparations. In the presence of KCl (60 mM), caffeic acid caused relaxations with the following EC50 values: 2.7 ± 0.26 mM/mL (aorta), 5.7 ± 0.71 mM/mL (uterus) and 2.1 ± 0.39 mM/mL (ileum). When in the presence of different agonists, PHE (0.1 μM) for the aorta, OT (10−2 IU/mL) for the uterus and CCh (10−6 M) for the ileum, caffeic acid caused relaxations with EC50 values of: 2.7 ± 0.31 mM/mL; 2.2 ± 0.34 mM/mL and 2.0 ± 0.28 mM/mL, respectively. The inhibitory effect of caffeic acid on serotonergic (aorta and uterus) and muscarinic receptors (uterus and ileum), as well as its possible involvement with L-type Ca2+ channels, was also observed. This study reports the pharmacological characterization of caffeic acid on smooth muscle from different organs, for which caffeic acid was more potent in the ileum. A diverse understanding of its performance as a possible therapeutic product is attributed to its relaxant effect.

Improving Small Intestinal Motility in Experimental Acute Necrotising Pancreatitis by Modulating the CPI-17/MLCP Pathway Using Chaiqin Chengqi Decoction.

Protein kinase C-potentiated inhibitor protein of 17 kDa (CPI-17), a specific inhibitor of myosin light-chain phosphatase (MLCP) regulated by proinflammatory cytokines, is central for calcium sensitisation. We investigated the effects of chaiqin chengqi decoction (CQCQD) on the CPI-17/MLCP pathway in the small intestinal smooth muscle cells (SMCs) and strips (SMS) in an AP model. Necrotising AP was induced in rats by intraperitoneal injections (IPI) of L-ornithine (3.0 g/kg, pH 7.0; hourly × 2) at 1 hour apart; controls received saline. In treatment groups, carbachol (CCh; 60 μg/kg, IPI) or CQCQD (20 g/kg; 2-hourly × 3, intragastric) was administered. The necrotising AP model was associated with systemic inflammation (serum IL-1β and TNF-α) and worsened jejunum histopathology and motility (serum vasoactive intestinal peptide and intestinal fatty acid-binding protein) as the disease progressed. There was decreased intracellular calcium concentration ([Ca2+]i) SMCs. Contractile function of isolated SMCs was reduced and associated with down-regulated expression of key mRNAs and proteins of the CPI-17/MLCP pathway as well as increased IL-1β and TNF-α. CQCQD and CCh significantly reversed these changes and the disease severity. These data suggest that CQCQD can improve intestinal motility by modulating the CPI-17/MLCP pathway in small intestinal smooth muscle during AP.

Comparison of two techniques for a comprehensive gut histopathological analysis: Swiss Roll versus Intestine Strips

Assessing the gut mucosa milieu is important to grade the inflammatory process in conditions such as food hypersensitivity, allergy, gut parasitosis, etc. However, the gastrointestinal tract comprises a challenging system to evaluate, due to its thin tubular structure and mucosa, which suffer fast autolysis after death. Irrespective of the preferred inflammatory score system, it is important to choose the technique that will render the best tissue analysis. Thus, our aim was to compare two of the most frequently used methods to collect, process and analyze gut segments, the Swiss Roll and the Intestinal Strips. Normal C57Bl/6 mice were randomly assigned to Rolls or Strips group. After an overdose of anesthetics, segments of the duodenum, jejunum and ileum were collected and prepared accordingly for histological processing and analysis. Our results show the villi in the Rolls tend to be shorter and wider than those in the Strips in the duodenum and jejunum but not the ileum. No significant differences were observed in intra-epithelial lymphocytes and goblet cells counts. Finally, we staged each segment using our histomorphometric classification system, which revealed that although all animals presented a normal intestinal mucosa, those assigned to the Rolls group had their mucosa staged in the Infiltrative Stage while the Strips group had their mucosa staged as Normal. In conclusion, Swiss Rolls might be desirable for a wider assessment of the intestine, as it allows large segments to be analyzed at once, while Strips are better suited when detailed evaluation of each villus is intended.

Ex vivo and in vivo effects of arsenite on GST and ABCC2 activity and expression in the middle intestine of the rainbow trout Oncorhynchus mykiss

In fish of freshwaters environments, the accumulation and toxic effects of arsenite (AsIII) can be attenuated by detoxification proteins such as GST and ABCC transporters. We studied the effects of AsIII on the middle intestine of O. mykiss in ex-vivo and in vivo/ex vivo assays. For the ex vivo assays, we measured the transport rate of the ABCC substrate DNP-SG and GST activity in intestinal strips and everted sacs. AsIII inhibited DNP-SG transport in a concentration-dependent manner, specifically when we applied it on the basolateral side. GST activity increased when we applied a maximum concentration of AsIII. For the in vivo/ex vivo assays, we kept fish in water with or without 7.7 μmol L−1 of AsIII for 48 h. Then, we measured DNP-SG transport rate, GST activity, and PP1 activity in intestine strips during one hour. For PP1 activity, we incubated the strips with or without microcystin-LR (MCLR), a toxin excreted through ABCC2 proteins. We also analyzed Abcc2 and Gst-π mRNA expression in intestine and liver tissue. In the group exposed in vivo to AsIII, DNP-SG transport rate and GST activity were higher and the effect of MCLR over PP1 activity was attenuated. AsIII significantly induced only Abcc2 mRNA expression in both middle intestine and liver. Our results suggest that, in the middle intestine of O. mykiss, AsIII is absorbed mainly at the basolateral side of the enterocytes, excreted to the lumen by ABCC2 transporters, and is capable of modulating Abcc2 mRNA expression by a transcriptional mechanism.

Galanin decreases spontaneous resting contractions and potentiates acetyl choline-induced contractions of goldfish gut

Galanin (GAL) is a 29 amino acid peptide, first identified from the porcine intestine and widely distributed within the brain and peripheral tissues. Among GAL biological functions, its role as a potent appetite-stimulating peptide is probably the most studied. With galanin's established role in the modulation of food intake in fish, this study aims to evaluate the effects of GAL on the intestinal motility of the goldfish, Carassius auratus, using an organ bath system. Our results found that application of GAL to the organ bath causes a significant concentration-dependent decrease in the amplitude of spontaneous contractions of goldfish gut. Preincubations of intestinal strips with acetylcholine (ACh) and GAL showed that GAL increases the force of ACh-induced contractions of the goldfish gut. These results provide the first evidence for a role of GAL in gut motility in goldfish. This also suggests a crosstalk between the effects of GAL and ACh in such functions, thus pointing to a putative joint role between the two molecules. These findings offer novel information that strengthens the role of the galaninergic system in fish feeding.