Protective effects of quercetin-loaded microcapsules on the enteric nervous system of diabetic rats.

Quercetin-loaded microcapsules (QLM) promote controlled release and higher bioavailability of quercetin, an antioxidant and neuroprotective agent. We evaluated the antioxidant effect of QLM on enteric innervation and in the oxidative status of the ileum of diabetic rats. Wistar adult rats (Rattus norvegicus) were used in six groups containing normoglycemic (N), diabetic (D) and either normoglycemic or diabetic groups treated with QLM at a dose of 10 mg/kg (NQ10 and DQ10, respectively) or 100 mg/kg (NQ100 and DQ100, respectively). DQ10 e DQ100 did not prevent overall neuronal loss in the total and cholinergic populations. Nitrergic population showed differences regarding the treatments: DQ10 preserved neurons in the nitrergic population whilst DQ100 increased nitrergic loss. Evaluation of the redox status showed pro-oxidant effects in NQ100 by t-butyl-induced chemiluminescence analysis. We observed a reduction in the carbonylic content and an increase of low molecular weight antioxidants for DQ10 e DQ100. Therefore, QLM treatment at a dose of 10 mg/kg acted positively on nitrergic neurons reducing oxidative damage induced by diabetes.

Anti- and pro-oxidant effects of quercetin stabilized by microencapsulation on interstitial cells of Cajal, nitrergic neurons and M2-like macrophages in the jejunum of diabetic rats.

Given the well-known antioxidant and neuroprotective properties of quercetin, the aim of this work was to evaluate the effects of quercetin stabilized by microencapsulation at two doses (10 mg kg-1 and 100 mg kg-1) on the oxidative/antioxidant status, number and morphological features of ICC, nitrergic neurons and M2-like macrophages in jejunum of diabetic rats. The rats were randomly distributed into six groups: normoglycemic control (N), diabetic control (D) and either normoglycemic or diabetic groups treated with quercetin-loaded microcapsules at a dose of 10 mg kg-1 (NQ10 and DQ10, respectively) or 100 mg kg-1 (NQ100 and DQ100, respectively). After 60 days, the jejunum was collected. Whole mounts were immunostained for Ano1, nNOS and CD206, and oxidative stress levels and total antioxidant capacity of the jejunum were measured. Diabetes led to a loss of ICC and nitrergic neurons, but increased numbers of M2-like macrophages and elevated levels of oxidative stress were seen in diabetic animals. High-dose administration of quercetin (100 mg kg-1) further aggravated the diabetic condition (DQ100) but this treatment resulted in harmful effects on healthy rats (NQ100), pointing to a pro-oxidant activity. However, low-dose administration of quercetin (10 mg kg-1) gave rise to antioxidant and protective effects on ICC, nNOS, macrophages and oxidative/antioxidant status in DQ100, but NQ100 displayed infrequent negative outcomes in normoglycemic animals. Microencapsulation of the quercetin may become promising alternatives to reduce diabetes-induced oxidative stress but antioxidant therapies should be careful used under healthy status to avoid toxic effects.

Cell Intrinsic Deregulated ß-Catenin Signaling Promotes Expansion of Bone Marrow Derived Connective Tissue Type Mast Cells, Systemic Inflammation, and Colon Cancer.

Mast cells constitutively express ß-catenin and expand in solid tumors such as colon and skin cancer. However, the role of ß-catenin signaling in mast cells and the cause or effect of mast cell expansion and tumor growth has yet to be established. In earlier studies we used mast cell depletion and protease staining approaches, to provide evidence for a causative role of mast cells in small bowel polyposis, and related specific phenotypes and distributions of tumor infiltrating mast cells to stages of tumor growth. Here we report that, stabilization of ß-catenin expands mast cells to promote high incidence of colon polyposis and infrequent small bowel polyps and skin cancer. Expression of a dominant acting ß-catenin in mast cells (5CreCAT) stimulated maturation and expression of granule stored proteases. Both mucosal and connective tissue type mast cells accumulated in colonic small bowel polyps independent of gender, and mice developed chronic systemic inflammation with splenomegaly. Reconstitution of polyposis-prone mice with bone marrow from 5CreCAT mice resulted in focal expansion of connective tissue like mast cells, which are normally rare in benign polyps and characteristically expand during adenoma-to-carcinoma transition. Our findings highlight a hitherto unknown contribution of ß-catenin signaling in mast cells to their maturation and to increased risk of colon cancer.

Rheumatoid arthritis induces enteric neurodegeneration and jejunal inflammation, and quercetin promotes neuroprotective and anti-inflammatory actions.

AIMS: The aim of our study was to study the pathological mechanisms induced by the rheumatoid arthritis (RA) on the Enteric Nervous System (ENS). MAIN METHODS: We evaluated the effect of the chronic arthritis and its treatment with 50 mg/kg quercetin alone (AQ) and combined with 17.5 mg/kg ibuprofen (AIQ) for 60 days on neurons, glial cells and intestinal wall. Other groups were used: control (C), arthritic (A) and arthritic treated with 17.5 mg/kg ibuprofen (AI). After 60 days, the jejunum was removed and processed for immunohistochemical techniques. Immunostainings were performed for HuC/D and S100 (myenteric and submucosal plexuses), and GFAP (only myenteric plexus), while immunolabeling for CD45 and CD20 lymphocytes was performed using cryosections. Western blot was performed for GDNF, S100 and GFAP. KEY FINDINGS: A group yielded a remarkable density decrease of the neurons and glial cells with morphometric changes in the myenteric and submucosal plexuses, reduction of the GDNF expression and GFAP-related parameters (GFAP expression, occupancy area and GFAP-expressing glial cells) and intestinal inflammation and atrophy of the mucosa and intestinal wall. AQ group substantially reversed most of these effects, except for intestinal atrophy of the jejunum. The AI and AIQ groups displayed lower beneficial results than AQ for parameters related to the neurons and glial cells, although AIQ did not prevent the inflammation of the mucosa. SIGNIFICANCE: The severe chronic rheumatoid arthritis induced severe effects on ENS and mucosa, and quercetin treatment continues to be an important antioxidant supplement preventing the progression of the RA severity.

Evaluation of the effects of autohemotransfusion in arthritic rats induced by two doses of complete Freund's adjuvant

The aim the study was to evaluate the effects of autohemotransfusion in adjuvant-induced arthritis model by injections of high and low doses of Complete Freund ́s Adjuvant (CFA). Male Holtzman rats (200-230g) were distributed in six groups: control (C); control treated by autohemotransfusion (CT); CFA induced arthritis 0.5% w/v (AIA); CFA induced arthritis 0.5% w/v treated with autohemotransfusion (AIAT); CFA induced arthritis 0.1% w/v (AS) and CFA induced arthritis 0.1% w/v treated with autohemotransfusion (AST). The number of leukocytes, the weight of different organs and the paw volume were analyzed. The autohemotransfusion without erythrocytes promoted a reduction in the number of leukocytes in AIAT and AST when compared to AIA (p 0.05). The autohemotransfusion used in this work presented positive effects on AIA as they promoted a reduction in the number of leukocytes and an increase in thymus weight and body growth. However, other types of autohemotransfusion must be tested to determine the true efficacy of this alternative method of treatment.

l-Glutamine supplementation promotes an improved energetic balance in Walker-256 tumor-bearing rats.

We evaluated the effects of supplementation with oral l-glutamine in Walker-256 tumor-bearing rats. A total of 32 male Wistar rats aged 54 days were randomly divided into four groups: rats without Walker-256 tumor, that is, control rats (C group); control rats supplemented with l-glutamine (CG group); Walker-256 tumor rats without l-glutamine supplementation (WT group); and WT rats supplemented with l-glutamine (WTG group). l-Glutamine was incorporated into standard food at a proportion of 2 g/100 g (2%). After 10 days of the experimental period, the jejunum and duodenum were removed and processed. Protein expression levels of key enzymes of gluconeogenesis, that is, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, were analyzed by western blot and immunohistochemical techniques. In addition, plasma corticosterone, glucose, insulin, and urea levels were evaluated. The WTG group showed significantly increased plasma glucose and insulin levels ( p < 0.05); however, plasma corticosterone and urea remained unchanged. Moreover, the WTG group showed increased immunoreactive staining for jejunal phosphoenolpyruvate carboxykinase and increased expression of duodenal glucose-6-phosphatase. Furthermore, the WTG group presented with less intense cancer cachexia and slower tumor growth. These results could be attributed, at least partly, to increased intestinal gluconeogenesis and insulinemia, and better glycemia maintenance during fasting in Walker-256 tumor rats on a diet supplemented with l-glutamine.

Supplementation with L-glutamine prevents tumor growth and cancer-induced cachexia as well as restores cell proliferation of intestinal mucosa of Walker-256 tumor-bearing rats.

This study aimed to evaluate the intestinal mucosa of the duodenum and jejunum of Walker-256 tumor-bearing rats supplemented with L-glutamine. Thirty-two male 50-day-old Wistar rats (Rattus norvegicus) were randomly divided into four groups: control (C), control supplemented with 2 % L-glutamine (GC), Walker-256 tumor (WT), and Walker-256 tumor supplemented with 2 % L-glutamine (TWG). Walker-256 tumor was induced by inoculation viable tumor cells in the right rear flank. After 10 days, celiotomy was performed and duodenal and jejunal tissues were removed and processed. We evaluated the cachexia index, proliferation index, villus height, crypt depth, total height of the intestinal wall, and number of goblet cells by the technique of periodic acid-Schiff (PAS). Induction of Walker-256 tumor promoted a reduction of metaphase index in the TW group animals, which was accompanied by a reduction in the villous height and crypt depths, resulting in atrophy of the intestinal wall as well as increased PAS-positive goblet cells. Supplementation with L-glutamine reduced the tumor growth and inhibited the development of the cachectic syndrome in animals of the TWG group. Furthermore, amino acid supplementation promoted beneficial effects on the intestinal mucosa in the TWG animals through restoration of the number of PAS-positive goblet cells. Therefore, supplementation with 2 % L-glutamine exhibited a promising role in the prevention of tumor growth and cancer-associated cachexia as well as restoring the intestinal mucosa in the duodenum and jejunum of Walker-256 tumor-bearing rats.

L-glutamine supplementation prevents myenteric neuron loss and has gliatrophic effects in the ileum of diabetic rats.

BACKGROUND: Peripheral neuropathy caused chronically by diabetes mellitus is related to exacerbation of oxidative stress and a significant reduction in important endogenous antioxidants. L: -Glutamine is an amino acid involved in defense mechanisms and is a substrate for the formation of glutathione, the major endogenous cellular antioxidant. AIM: This study investigated the effects of 2% L: -glutamine supplementation on peripheral diabetic neuropathy and enteric glia in the ileum in rats. METHODS: Male Wistar rats were divided into four groups: normoglycemics (N), normoglycemics supplemented with L: -glutamine (NG), diabetics (D), and diabetics supplemented with L: -glutamine (DG). After 120 days, the ileums were processed for HuC/D and S100 immunohistochemistry. Quantitative and morphometric analysis was performed. RESULTS: Diabetes significantly reduced the number of HuC/D-immunoreactive myenteric neurons per unit area and per ganglion in group D compared with normoglycemic animals (group N). L: -Glutamine (2%) prevented neuronal death induced by diabetes (group DG) compared with group D. The glial density per unit area did not change with diabetes (group D) but was significantly reduced after L: -glutamine supplementation (groups NG and DG). Ganglionic glial density was similar among the four groups. The neuronal area was not altered in groups D and DG. Glial size was reduced in group D; this was reversed by L: -glutamine supplementation (group DG). CONCLUSIONS: We concluded that 2% L: -glutamine had neuroprotective effects directly on myenteric neurons and indirectly through glial cells, which had gliatrophic effects.