oxytocin and Colitis

Topics: Amenorrhea; Breast Feeding; Cesarean Section; Colitis; Diet; Female; Humans; Immunity, Maternally-Acquired; Infant Care; Infant, Newborn; Infant, Newborn, Diseases; Jaundice, Neonatal; Lactation; Mastitis; Milk, Human; Nutritive Value; Obesity; Oxytocin; Postpartum Period; Pregnancy; Prolactin

Emerging evidence suggests that the nervous system is involved in tumor development in the periphery, however, the role of the central nervous system remains largely unknown. Here, by combining genetic, chemogenetic, pharmacological, and electrophysiological approaches, we show that hypothalamic oxytocin (Oxt)-producing neurons modulate colitis-associated cancer (CAC) progression in mice. Depletion or activation of Oxt neurons could augment or suppress CAC progression. Importantly, brain treatment with celastrol, a pentacyclic triterpenoid, excites Oxt neurons and inhibits CAC progression, and this anti-tumor effect was significantly attenuated in Oxt neuron-lesioned mice. Furthermore, brain treatment with celastrol suppresses sympathetic neuronal activity in the celiac-superior mesenteric ganglion (CG-SMG), and activation of β2 adrenergic receptor abolishes the anti-tumor effect of Oxt neuron activation or centrally administered celastrol. Taken together, these findings demonstrate that hypothalamic Oxt neurons regulate CAC progression by modulating the neuronal activity in the CG-SMG. Stimulation of Oxt neurons using chemicals, for example, celastrol, might be a novel strategy for colorectal cancer treatment.. Colorectal (or ‘bowel’) cancer killed nearly a million people in 2018 alone: it is, in fact, the second leading cause of cancer death globally. Lifestyle factors and inflammatory bowel conditions such as chronic colitis can heighten the risk of developing the disease. However, research has also linked to the development of colorectal tumours to stress, anxiety and depression. This ‘brain-gut’ connection is particularly less-well understood. One brain region of interest is the hypothalamus, an almond-sized area which helps to regulate mood and bodily processes using chemical messengers that act on various cells in the body. For instance, Oxt neurons in the hypothalamus produce the hormone oxytocin which regulates emotional and social behaviours. These cells play an important role in modulating anxiety, stress and depression. To investigate whether they could also influence the growth of colorectal tumours, Pan et al. used various approaches to manipulate the activity of Oxt neurons in mice with colitis-associated cancer. Disrupting the Oxt neurons in these animals increased anxiety-like behaviours and promoted tumour growth. Stimulating these cells, on the other hand, suppressed cancer progression. Further experiments also showed that treating the mice with celastrol, a plant extract which can act on the hypothalamus, stimulated Oxt neurons and reduced tumour growth. In particular, the compound worked by acting on a nerve structure in the abdomen which relays messages to the gut. These preliminary findings suggest that the hypothalamus and its Oxt-producing neurons may influence the progression of colorectal cancer in mice by regulating the activity of an abdominal ‘hub’ of the nervous system. Modulating the activity of Oxt-producing neurons could therefore be a potential avenue for treatment.

Topics: Animals; Azoxymethane; Colitis; Colorectal Neoplasms; Dextran Sulfate; Hypothalamus; Mice, Inbred C57BL; Mice, Transgenic; Neurons; Oxytocin; Pentacyclic Triterpenes

The aim of the current study was to investigate the effect of macrophage polarization on the expression of oxytocin (OT) and the oxytocin receptor (OTR) in enteric neurons.. In this study, we used a classic colitis model and D-mannose model to observe the correlation between macrophage polarization and OT signalling system. In order to further demonstrate the effect of macrophages, we examined the expression of OT signalling system after depletion of macrophages.. The data showed that, in vitro, following polarization of macrophages to the M1 type by LPS, the macrophage supernatant contained proinflammatory cytokines (IL-1β, IL-6 and TNF-α) that inhibited the expression of OT and OTR in cultured enteric neurons; following macrophage polarization to the M2 type by IL4, the macrophage supernatant contained anti-inflammatory cytokines (TGF-β) that promoted the expression of OT and OTR in cultured enteric neurons. Furthermore, M1 macrophages decreased the expression of the OT signalling system mainly through STAT3/NF-κB pathways in cultured enteric neurons; M2 macrophages increased the expression of the OT signalling system mainly through activation of Smad2/3 and inhibition of the expression of Peg3 in cultured enteric neurons. In a colitis model, we demonstrated that macrophages were polarized to the M1 type during the inflammatory phase, with significant decreased in the expression of OT and OTR. When macrophages were polarized to the M2 type during the recovery phase, OT and OTR expression increased significantly. In addition, we found that D-mannose increased the expression of OT and OTR through polarization of macrophages to the M2 type.. This is the first study to demonstrate that macrophage polarization differentially regulates the expression of OT and OTR in enteric neurons.

Topics: Animals; Cell Differentiation; Colitis; Enteric Nervous System; Macrophages; Mice; Mice, Inbred C57BL; Neurons; Oxytocin; Receptors, Oxytocin; Signal Transduction

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) that is associated with immune dysfunction. Recent studies have indicated that the neurosecretory hormone oxytocin (OXT) has been proven to alleviate experimental colitis.. We investigated the role of OXT/OXT receptor (OXTR) signalling in dendritic cells (DCs) using mice with specific OXTR deletion in CD11c+ cells (OXTRflox/flox×CD11c-cre mice) and a dextran sulfate sodium (DSS)-induced colitis model.. The level of OXT was abnormal in the serum or colon tissue of DSS-induced colitis mice or the plasma of UC patients. Both bone marrow-derived DCs (BMDCs) and lamina propria DCs (LPDCs) express OXTR. Knocking out OXTR in DCs exacerbated DSS-induced acute and chronic colitis in mice. In contrast, the injection of OXT-pretreated DCs significantly ameliorated colitis. Mechanistically, OXT prevented DC maturation through the phosphatidylinositol 4,5-bisphosphate 3-kinase (Pi3K)/AKT pathway and promoted phagocytosis, adhesion and cytokine modulation in DCs. Furthermore, OXT pre-treated DCs prevent CD4+ T cells differentiation to T helper 1 (Th1) and Th17.. Our results suggest that OXT-induced tolerogenic DCs efficiently protect against experimental colitis via Pi3K/AKT pathway. Our work provides evidence that the nervous system participates in the immune regulation of colitis by modulating DCs. Our findings suggest that generating ex vivo DCs pretreated with OXT opens new therapeutic perspectives for the treatment of UC in humans.

Topics: Adult; Aged; Aged, 80 and over; Animals; Colitis; Colitis, Ulcerative; Dendritic Cells; Dextran Sulfate; Disease Models, Animal; Female; Humans; Male; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Oxytocin; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Receptors, Oxytocin; Signal Transduction

Inflammatory bowel disease (IBD) is a chronic intestinal inflammation, but the accurate etiology remains to be elucidated. Increasing evidence has shown that macrophages polarize to different phenotypes depending on the intestinal microenvironment and are associated with the progression of IBD. In the present study, we investigated the effect of oxytocin, a neuroendocrinal, and pro-health peptide, on the modulation of macrophages polarization and the progression of experimental colitis. Our data demonstrated that oxytocin decreased the sensitivity of macrophages to lipopolysaccharide stimulation with lower expression of inflammatory cytokines, like IL-1β, IL-6, and TNF-α, but increased the sensitivity to IL-4 stimulation with enhanced expression of M2-type genes, arginase I (Arg1), CD206, and chitinase-like 3 (Chil3). This bidirectional modulation was partly due to the up-regulation of β-arrestin2 and resulted in the inhibition of NF-κB signaling and reinforcement of Signal transducer and activator of transcription (STAT) 6 phosphorylation. Moreover, oxytocin receptor (OXTR) myeloid deficiency mice were more susceptible to dextran sulfate sodium (DSS) intervention compared with the wild mice. For the first time, we reveal that oxytocin-oxytocin receptor system participates in modulating the polarization of macrophages to an anti-inflammatory phenotype and alleviates experimental colitis. These findings provide new potential insights into the pathogenesis and therapy of IBD.

Topics: Adult; Aged; Animals; beta-Arrestins; Cell Polarity; Colitis; Dextran Sulfate; Female; Humans; Inflammation; Inflammation Mediators; Interleukin-4; Intestines; Lipopolysaccharides; Macrophages; Male; Mice; Mice, Knockout; Middle Aged; Models, Biological; NF-kappa B; Oxytocin; Phosphorylation; RAW 264.7 Cells; Receptors, Oxytocin; STAT6 Transcription Factor; THP-1 Cells

This study was conducted to investigate the effects of oxytocin (OT) on visceral hypersensitivity/pain and mast cell degranulation and the underlying mechanisms. We found that oxytocin receptor (OTR) was expressed in colonic mast cells in humans and rats, as well as in human mast cell line-1 (HMC-1), rat basophilic leukemia cell line (RBL-2H3) and mouse mastocytoma cell line (P815). OT decreased 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced visceral hypersensitivity, colonic mast cell degranulation and histamine release after mast cell degranulation in rats. Also, OT attenuated the compound 48/80 (C48/80)-evoked histamine release in P815 cells and inward currents, responsible for the mast cell degranulation, in HMC-1, RBL-2H3 and P815 cells. Moreover, these protective effects of OT against visceral hypersensitivity and mast cell degranulation were eliminated by coadministration of OTR antagonist atosiban or a nonselective inhibitor of nitric oxide synthase (NOS), NG-Methyl-L-arginine acetate salt (L-NMMA). Notably, OT evoked a concentration-dependent increase of intracellular Ca(2+) in HMC-1, RBL-2H3 and P815 cells, which was responsible for the activation of neuronal NOS (NOS1) and endothelial NOS (NOS3). Our findings strongly suggest that OT might exert the antinociception on colonic hypersensitivity through inhibition of mast cell degranulation via Ca(2+)-NOS pathway.

Topics: Analgesics; Animals; Calcium; Cell Degranulation; Cell Line; Colitis; Colon; Evoked Potentials; Histamine Release; Humans; Male; Mast Cells; Microscopy, Confocal; Nitric Oxide Synthase; omega-N-Methylarginine; Oxytocin; Patch-Clamp Techniques; Rats; Rats, Wistar; Receptors, Oxytocin; Signal Transduction; Trinitrobenzenesulfonic Acid; Vasotocin

The potential protective effect of OT on a stress-aggravated colitis model in rats and the involvement of OT receptors were evaluated. Holeboard test performances of Sprague-Dawley rats were videotaped for 5min to evaluate their exploratory behavior as indices of anxiety levels. A subgroup of rats was exposed to a 30-min psychological stress procedure, "water avoidance stress", for 5 consecutive days. Colitis was induced by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS, 30mg/ml), while the sham group was administered with intracolonic saline. Either OT (0.5mg/kg/day; subcutaneously) or OT + OT receptor antagonist atosiban, was given (1mg/kg/day; intraperitoneally) for 3 consecutive days after colitis induction. On the third day, holeboard tests were performed again and the rats were decapitated. Macroscopic lesions were scored and the degree of oxidant damage was evaluated by colonic myeloperoxidase activity (MPO), malondialdehyde (MDA) and glutathione (GSH) levels, and by histological analysis. Colitis induction inhibited exploratory behavior, indicating increased anxiety level, while exposure to stress further exaggerated the degree of anxiety. Macroscopic scores as well as MDA and MPO levels revealed that tissue damage is aggravated in the stressed group with colitis while antioxidant GSH levels were decreased in both colitis and stressed colitis groups. Oxytocin treatment decreased the exacerbated anxiety, MPO and MDA levels and inflammatory cell infiltration and submucosal edema while atosiban abolished all the protective effects of OT. Thus, the results showed that the anxiolytic and antioxidant effects of OT are mediated via its receptors, since atosiban reversed the protective impact of OT on colonic injury while blocking its stress-relieving effect.

Topics: Animals; Anxiety; Colitis; Colon; Female; Male; Oxytocin; Rats; Rats, Sprague-Dawley; Receptors, Oxytocin; Stress, Psychological; Trinitrobenzenesulfonic Acid; Vasotocin

The pathogenesis of inflammatory bowel disease is unknown; however, the disorder is aggravated by psychological stress and is itself psychologically stressful. Chronic intestinal inflammation, moreover, has been reported to activate forebrain neurons. We tested the hypotheses that the chronically inflamed bowel signals to the brain through the vagi and that administration of a combination of secretin (S) and oxytocin (OT) inhibits this signaling.. Three daily enemas containing 2,4,6-trinitrobenzene sulfonic acid (TNBS), which were given to rats produced chronic colitis and ongoing activation of Fos in brain neurons.. Fos was induced in neurons in the paraventricular nucleus of the hypothalamus, basolateral amygdala, central amygdala, and piriform cortex. Subdiaphragmatic vagotomy failed to inhibit this activation of Fos, suggesting that colitis activates forebrain neurons independently of the vagi. When administered intravenously, but not when given intracerebroventricularly, in doses that were individually ineffective, combined S/OT prevented colitis-associated activation of central neurons. Strikingly, S/OT decreased inflammatory infiltrates into the colon and colonic expression of tumor necrosis factor-alpha and interferon-gamma.. These observations suggest that chronic colonic inflammation is ameliorated by the systemic administration of S/OT, which probably explains the parallel ability of systemic S/OT to inhibit the colitis-associated activation of forebrain neurons. It is possible that S and OT, which are endogenous to the colon, might normally combine to restrict the severity of colonic inflammatory responses and that advantage might be taken of this system to develop novel means of treating inflammation-associated intestinal disorders.

Topics: Amygdala; Animals; Cerebral Cortex; Chronic Disease; Colitis; Genes, fos; Injections, Intraperitoneal; Injections, Intraventricular; Interferon-gamma; Intestinal Mucosa; Male; Neurons; Oxytocin; Paraventricular Hypothalamic Nucleus; Prosencephalon; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Secretin; Signal Transduction; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha; Vagotomy

The impact of colitis on uterine contractility and estrous cycle was investigated after intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats. Colitis severity was assessed by macroscopic damage scoring (MDS) 4 days after TNBS, and myeloperoxidase (MPO) activity was measured in both colon and uterus of control and colitic rats. Estrous cycle stages were determined by vaginal smears and histology, and uterine contractility was assessed in vitro on longitudinal and circular strips. In control rats, uterine MPO activity varied markedly during the cycle and peaked around estrus. In rats with moderate colitis [MDS < 5, 3.1 +/- 0.2 (mean +/- SE)], uterine MPO decreased by 61% compared with estrus control, without disruption of the cycle. Frequency of spontaneous contractions was reduced by 32% in circular muscle. Contractile responses to KCl and carbachol were not affected, whereas maximal response to oxytocin decreased by 47% in the longitudinal muscle. In rats with severe colitis (MDS > 5, 6.0 +/- 0.2), uterine MPO was reduced by 96% and estrous cycle was disrupted. Spontaneous contractility was impaired in circular strips, and a 39% decrease in the contraction frequency occurred in the longitudinal strips. Circular strips did not contract to KCl or carbachol; however, longitudinal strips had maximal responses to KCl, carbachol, and oxytocin reduced by 36%, 27%, and 46%, respectively. Estrogen replacement protected the uterine responses to carbachol in colitic rats, whereas oxytocin responses remained depressed. These data indicate that colonic inflammation can influence both spontaneous and evoked uterine contractility, in relation to estrous cycle disturbances, impaired estradiol production, and functional alterations of myometrial cells.

Topics: Animals; Carbachol; Colitis; Colon; Estrus; Female; In Vitro Techniques; Muscarinic Agonists; Oxytocin; Peroxidase; Potassium Chloride; Rats; Rats, Sprague-Dawley; Trinitrobenzenesulfonic Acid; Uterine Contraction; Uterus

Oxytocin (OT), a nonapeptide produced in the paraventricular and the supraoptical nuclei in the hypothalamus has a wide range of effects in the body. However, the role of OT on the gastrointestinal (GI) tract has to be settled. OT may participate in the regulation of motility, secretion, blood flow, cell turnover and release of neurotransmitters and/or peptides in the GI tract, possesses antisecretory and antiulcer effects, facilitates wound healing and is involved in the modulation of immune and inflammatory processes. The present work was conducted to assess the possible therapeutic effects of OT against the acetic acid-induced colonic injury in the rat.. Colitis was induced by intracolonic administration of acetic acid (5%) in Sprague-Dawley rats (200-250 g). Either saline or OT (0.5 mg/kg) was injected subcutaneously, immediately after the induction of colitis and repeated two times a day for 4 days. On the 4th day, rats were decapitated and distal 8 cm of the colon were removed for the macroscopic and microscopic damage scoring, determination of tissue wet weight index (WI), malondialdehyde (MDA) levels, an end product of lipid peroxidation; glutathione (GSH) levels, a key antioxidant; and myeloperoxidase (MPO) activity, as an indirect index of neutrophil infiltration. Colonic collagen content, as a fibrosis marker was also determined. Lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-alpha) levels were assayed in serum samples. In the acetic acid-induced colitis, macroscopic and microscopic damage scores, WI, MDA and MPO levels were significantly increased, while GSH levels were decreased when compared to control group (p <0.05-<0.001). Treatment with OT abolished the colitis-induced elevations in damage scores, WI, MDA and MPO levels and restored the GSH levels (p <0.05-0.001). Similarly, acetic acid increased the collagen content of colonic tissues and OT-treatment reduced this value to the level of the control group. Serum LDH and TNF-alpha levels were also elevated in the acetic acid-induced colitis group as compared to control group, while this increase was significantly decreased by OT treatment. The results suggest that OT, which improves the antioxidative state of the colonic tissue and ameliorates oxidative colonic injury via a neutrophil-dependent mechanism, requires further investigation as a potential therapeutic agent in colonic inflammation.

Topics: Acetic Acid; Animals; Antioxidants; Colitis; Colon; Female; Gastrointestinal Tract; Glutathione; Immune System; Inflammation; L-Lactate Dehydrogenase; Lipid Peroxidation; Neutrophils; Oxidants; Oxidation-Reduction; Oxygen; Oxytocin; Peroxidase; Rats; Rats, Sprague-Dawley; Time Factors; Tumor Necrosis Factor-alpha