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.

Quercetin increases bioavailability of nitric oxide in the jejunum of euglycemic and diabetic rats and induces neuronal plasticity in the myenteric plexus.

Considering the antioxidant, neuroprotective, inflammatory and nitric oxide modulatory actions of quercetin, the aim of this study was to test the effect of quercetin administration in drinking water (40 mg/day/rat) on neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP), overall population of myenteric neurons (HuC/D) and nitric oxide (NO) levels in the jejunal samples from diabetic rats. Male Wistar rats were distributed into four groups (8 rats per group): euglycemic (E), euglycemic administered with quercetin (E+Q), diabetic (D) and diabetic administered with quercetin (D+Q). Rats were induced to diabetes with streptozotocin (35mg/kg/iv) and, after 120 days, the proximal jejunum were collected and processed for immunohistochemical (VIP, nNOS and HuC/D) and chemiluminescence (quantification of tissue NO levels) techniques. Diabetes mellitus reduced the number of nNOS-IR (immunoreactive) (p <0.05) and HuC/D-IR (p <0.001) neurons, however, promoted an increased morphometric area of nNOS-IR neurons (p <0.001) and VIP-IR varicosities (p <0.05). In D+Q group, neuroplasticity effects were observed on HuC/D-IR neurons, accompanied by a reduction of cell body area of neurons nNOS- and VIP-IR varicosities (p <0.05). The NO levels were increased in the E+Q (p <0.05) and D+Q group (p <0.001) compared to the control group. In conclusion, the results showed that quercetin supplementation increased the bioavailability of NO in the jejunum in euglycemic and mitigate the effects of diabetes on nNOS-IR neurons and VIP-IR varicosities in the myenteric plexus of diabetic rats.

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.

QUERCETIN SUPPLEMENTATION PREVENTS CHANGES IN THE SEROTONIN AND CASPASE-3 IMMUNOREACTIVE CELLS OF THE JEJUNUM OF DIABETIC RATS.

BACKGROUND: Serotonin (5-HT) is present in the epithelial enterochromaffin cells (EC), mast cells of the lamina propria and enteric neurons. The 5-HT is involved in regulating motility, secretion, gut sensation, immune system and inflammation. OBJECTIVE: Evaluate the effects of diabetes and quercetin supplementation on serotoninergic cells and its cell loss by apoptosis in jejunal mucosa of streptozotocin-induced diabetic rats (STZ-rats). METHODS: Twenty-four male Wistar rats were divided into four groups: normoglycemic (C), normoglycemic supplemented with 40 mg/day quercetin (Q), diabetic (D) and diabetic supplemented with 40 mg/day quercetin (DQ). After 120 days, the jejunum was collected and fixated in Zamboni's solution for 18 h. After obtaining cryosections, immunohistochemistry was performed to label 5-HT and caspase-3. Quantification of 5-HT and caspase-3 immunoreactive (IR) cells in the lamina propria, villi and crypts were performed. RESULTS: The diabetic condition displayed an increase of the number of 5-HT-IR cells in villi and crypts, while decreased number of these cells was observed in lamina propria in the jejunum of STZ-rats. In the diabetic animals, an increased density of apoptotic cells in epithelial villi and crypts of the jejunum was observed, whereas a decreased number of caspase-3-IR cells was observed in lamina propria. Possibly, quercetin supplementation slightly suppressed the apoptosis phenomena in the epithelial villi and crypts of the STZ-rats, however the opposite effect was observed on the 5-HT-IR cells of the lamina propria. Quercetin supplementation on healthy animals promoted few changes of serotoninergic function and apoptotic stimuli. CONCLUSION: These results suggest that quercetin supplementation mostly improved the serotonergic function affected by diabetes maybe due to antioxidant and anti-inflammatory properties of quercetin.

A suplementação com quercetina previne mudanças em células imunorreativas à serotonina e caspase-3 do jejuno de ratos diabéticos / Quercetin supplementation prevents changes in the serotonin and caspase-3 immunoreactive cells of the jejunum of diabetic rats

ABSTRACT BACKGROUND: Serotonin (5-HT) is present in the epithelial enterochromaffin cells (EC), mast cells of the lamina propria and enteric neurons. The 5-HT is involved in regulating motility, secretion, gut sensation, immune system and inflammation. OBJECTIVE: Evaluate the effects of diabetes and quercetin supplementation on serotoninergic cells and its cell loss by apoptosis in jejunal mucosa of streptozotocin-induced diabetic rats (STZ-rats). METHODS: Twenty-four male Wistar rats were divided into four groups: normoglycemic (C), normoglycemic supplemented with 40 mg/day quercetin (Q), diabetic (D) and diabetic supplemented with 40 mg/day quercetin (DQ). After 120 days, the jejunum was collected and fixated in Zamboni's solution for 18 h. After obtaining cryosections, immunohistochemistry was performed to label 5-HT and caspase-3. Quantification of 5-HT and caspase-3 immunoreactive (IR) cells in the lamina propria, villi and crypts were performed. RESULTS: The diabetic condition displayed an increase of the number of 5-HT-IR cells in villi and crypts, while decreased number of these cells was observed in lamina propria in the jejunum of STZ-rats. In the diabetic animals, an increased density of apoptotic cells in epithelial villi and crypts of the jejunum was observed, whereas a decreased number of caspase-3-IR cells was observed in lamina propria. Possibly, quercetin supplementation slightly suppressed the apoptosis phenomena in the epithelial villi and crypts of the STZ-rats, however the opposite effect was observed on the 5-HT-IR cells of the lamina propria. Quercetin supplementation on healthy animals promoted few changes of serotoninergic function and apoptotic stimuli. CONCLUSION: These results suggest that quercetin supplementation mostly improved the serotonergic function affected by diabetes maybe due to antioxidant and anti-inflammatory properties of quercetin.

RESUMO CONTEXTO: A serotonina (5-HT) está presente nas células epiteliais enterocromafins (CE), nos mastócitos da lâmina própria e nos neurônios entéricos. A 5-HT está envolvida na regulação da motilidade, secreção, nocepção intestinal, sistema imunológico e inflamação. Objetivo: Avaliar os efeitos do diabetes e da suplementação de quercetina sobre a função serotoninérgica e a perda celular por apoptose na mucosa jejunal de ratos diabéticos induzidos por estreptozotocina (ratos STZ). MÉTODOS: Vinte e quatro ratos Wistar machos foram divididos em quatro grupos: normoglicêmico (C), normoglicêmico suplementado com quercetina 40 mg/dia (Q), diabético (D) e diabético suplementado com quercetina 40 mg/dia (DQ). Após 120 dias, o jejuno foi coletado e fixado na solução de Zamboni por 18 horas. Após a obtenção de cortes em criostato, a imuno-histoquímica foi realizada para marcar 5-HT e caspase-3. A quantificação de células imunorreativas (IR) à 5-HT e caspase-3 foram realizadas na lâmina própria, vilosidades e criptas. RESULTADOS: A condição diabética ocasionou um aumento do número de células 5-HT-IR nas vilosidades e criptas, enquanto que na lâmina própria houve uma redução dessas células, no jejuno de ratos STZ. Nos animais diabéticos, foi observada uma densidade aumentada de células apoptóticas no epitélio do jejuno, tanto nas vilosidades quanto nas criptas, por outro lado um número reduzido de células caspase-3-IR foi observado na lâmina própria. Possivelmente, a suplementação de quercetina suprimiu ligeiramente os fenômenos de apoptose no epitélio de vilosidades e criptas do jejuno de ratos STZ, no entanto, o efeito oposto foi observado nas células 5-HT-IR da lâmina própria. A suplementação com quercetina em animais saudáveis promoveu poucas alterações na função serotoninérgica e nos estímulos apoptóticos. CONCLUSÃO: Estes resultados sugerem que a suplementação de quercetina melhorou principalmente a função serotoninérgica afetada pelo diabetes, talvez devido às propriedades antioxidantes e anti-inflamatórias da quercetina.

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.

Restoration of density of interstitial cells of Cajal in the jejunum of diabetic rats after quercetin supplementation

Background: Interstitial cells of Cajal (ICC) are required for normal motility in the gastrointestinal tract. Depletion of ICC has been associated with diabetic gastroenteropathy. Aim: To determine the effect of quercertin supplementation on anoctamin-1 (Ano 1) immunoreactive ICC in the myenteric region (ICC-MY) and deep muscular plexus (ICC-DMP) in the jejunum of diabetic rats. Methods: Thirty-two 90-day-old male Wistar rats were distributed into the following groups: normoglycemic (C), normoglycemic supplemented with quercetin (CQ; 40 mg daily), diabetic (D), and diabetic supplemented with quercetin (DQ; 40 mg daily). Diabetes was induced by streptozotocin injection. After 120 days, preparations of the jejunal muscular and submucosal layers were immunostained for Ano1 to visualize ICC. Evaluation of the immunofluorescence intensity as well as density of ICC was performed. Results: The density of ICC-MY was 46% lower in group D compared to group C (p < 0.01); ICC-DMP were reduced by 37% (p > 0.05). After quercertin treatment, the densities of ICCMY were significantly higher in the DQ group compared to group D (ICC-MY: 58%, p < 0.05). Supplementation with quercetin in normoglycemic animals (CQ) compared with group C did not significantly change the ICC density (p > 0.05). Conclusions: In STZ-treated diabetic rats, diabetes promoted a reduction in the density of jejunal ICC-MY with no significant effect on ICC-DMP. Supplementation with quercetin (DQ) appeared to protect ICC-MY from depletion in diabetes possibly due to its antioxidant action (AU)

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Antioxidant Effects of the Quercetin in the Jejunal Myenteric Innervation of Diabetic Rats.

PURPOSE: Enteric glial cells (EGCs) exert a critical role in the structural integrity, defense, and metabolic function of enteric neurons. Diabetes mellitus is a chronic disease characterized by metabolic disorders and chronic autonomic neuropathy. Quercetin supplementation, which is a potent antioxidant, has been used in order to reduce the effects of diabetes-induced oxidative stress. The purpose of this research was to investigate the effects of quercetin supplementation in the drinking water at a daily dose of 40 mg on the glial cells and neurons in the jejunum of diabetic rats. MATERIALS AND METHODS: Twenty 90-day-old male adult Wistar rats were split into four groups: normoglycemic control (C), normoglycemic control supplemented with quercetin (Q), diabetic (D), and diabetic supplemented with quercetin (DQ). After 120 days, the jejunums were collected, and immunohistochemical technique was performed to label S-100-immunoreactive glial cells and HuC/D-immunoreactive neurons. RESULTS: An intense neuronal and glial reduction was observed in the jejunum of diabetic rats. Quercetin displayed neuroprotective effects due to reduced cell body areas of neurons and glial cells in Q and DQ groups compared to their controls (C and D groups). Interestingly, quercetin prevented the glial and neuronal loss with a higher density for the HuC/D-immunoreactive neurons (23.06%) and for the S100-immunoreactive glial cells (14.55%) in DQ group compared to D group. CONCLUSION: Quercetin supplementation promoted neuroprotective effects through the reduction of neuronal and glial body areas and a slight prevention of neuronal and glial density reduction.

Spatial distribution of intestinal parasitic infections in a Kaingáng indigenous village from Southern Brazil.

The spatial distribution of enteroparasitosis in an indigenous village from Paraná was evaluated to identify areas of risk for these infections. A cross-sectional study (from November 2010 to June 2011) was performed using Three Faecal Test(®) and Kato & Katz method and a questionnaire on housing and hygiene conditions was administered. Local geostatistical analyses were performed to determine the spatial distribution of intestinal parasitic infections. The overall prevalence of enteroparasites was 67.2 % (457/680), and the most prevalent taxa were Ascaris lumbricoides (48.8 %) and Trichuris trichiura (44.7 %). The prevalence of heavy infection by soil-transmitted helminths was 3.6 % and the families lived in houses with an average of 5.1 residents and < 2 bedrooms per household. The average number of species per individual present spatial heterogeneity with the highest values (≥0.8) in areas with high clustering of residences. The visualization of the spatial distribution of intestinal parasites in this indigenous village is an important contribution to determining health risk areas and planning decisions and services.

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.

Biological behaviour in mice of Trypanosoma cruzi isolates from Amazonas and Paraná, Brazil.

The biological behaviour of 23 Trypanosoma cruzi isolates in Swiss mice was compared. Nineteen isolates were obtained from patients in the acute phase of Chagas disease (13), sylvatic reservoir hosts (Didelphis marsupialis) (3), and triatomine bugs (Rhodnius robustus) (3) from four regions of the State of Amazonas (AM). Four isolates were obtained from chronic chagasic patients in the State of Paraná (PR): three autochthones, and one allochthone from the State of Minas Gerais. Only one isolate was unable to infect the mice. The AM and PR isolates showed the largest number of significant differences from each other. The former had lower mean values in the pre-patent (5.4 days) and patent (4.6 days) periods (PP), with the parasitaemia (Pmax) reaching a peak of 9.9×10(4) blood trypomastigotes (BT)/mL of blood by the 7th day following inoculation. The AM isolates also had higher positivity to fresh-blood examination (FBE) (84.1%) compared to haemoculture (HC) (58.7%) and polymerase chain reaction (PCR) (33.3%), in addition to higher mortality (2.9%). The PR isolates had higher values for PP (18.5 days) and Pmax (99.9×10(4)BT/mL) as well as higher positivity to FBE (87.2%), HC (100%), and PCR (83.3%). The correlations between the biological behaviour of the T. cruzi isolates and the clinical and epidemiological characteristics of Chagas disease are discussed.