Dieta rica em fontes de fibras alimentares : efeitos sobre a mucosa gastrointestinal ulcerada de ratos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Works have related the consumption of dietary fibers, mainly in the soluble form, with the increase of the protective capacity of the gastric and duodenal mucous membranes. The orange pulp (OP), the guar gum (GG) and the (100:40) mixture orange pulp/guar gum (OPG) were used as fiber sources and the physical and physicochemical characteristics were characterized, presenting the following results: total fibers (82.6%, 71.1 % and 76.1 %, respectively); GG presented predominance of soluble fraction (75%), while OP and OPG presented 32.2% and 32.6% of insoluble fraction, respectively. The antiulcerogenic effects of OP, GG and OPG were verified in acute models of gastric ulcer by ethanol, indomethacin, pylorus ligature and chronic ulcer by acetic acid, besides the model of duodenal ulcer by cysteamine. The effect of OP, GG and OPG were also investigated in the determination of mucus adhered to gastric mucous, in the prostaglandin synthesis and under the plasmatic concentrations of gastrin and somatostatin. The fibers sources were provided by: 1) gavage in a single dose of 160 mg/Kg (acute treatment) diluted in saline, previously to the inductor agent of ulcer; 2) included in the diet (20%) replacing amidogen during 30 days (chronic ingestion). OP, chronically provided, protected the gastric mucous only in the model of pylorus ligature (64%) and reduced the mortality rate of the animals in the cysteamine model, while GG and OPG presented significant reparation in the acetic-acid ulcer model (37.3% and 39.4%, respectively), reduced the incidence of duodenal ulcer (20% and 30%, respectively) and avoided the death of animals in the cysteamine model (0% for both). OP, acutely provided, only inhibited gastric lesion in the indomethacin model (30%) and reduced the area of intestinal lesion in the cysteamine model (87.5%), while GG and OPG presented significant gastric protection in the ethanol (67.8% and 50.7%, respectively), indomethacin (81.3% and 83.4%, respectively) and pylorus ligature (67% and 58%, respectively) models. GG and OPG also produced significant change in the gastric secretion (increase of 358% and 260%, respectively), in pH (increase of 212% and 157%, respectively) and in the total acid concentration (decrease of 30% and 54%, respectively). However, considering the cysteamine agent, OPG did not offer significant protection and GG reduced in 68.8% the area of ulcerous lesion. GG and OPG increased significantly the synthesis of prostaglandin in the gastric mucous (38% and 37%, respectively), as well as the concentration of cytoprotector mucus (84% and 40%, respectively). GG and OPG also promoted significant reduction (80%) in the plasmatic gastrin levels and increase in the somatostatin levels (210% and 300%, respectively). Morphologic analysis of the stomach of rats submitted to chronic ingestion of diets with GG and OPG did not show significant changes, while OP reduced in 42% the thickness of the gastric muscular layer compared to control animals. The number of secretor cells of the gastric-region mucus was significantly greater in the animals that were submitted to enriched GG and OPG diets (32.5% and 37.3%, respectively). The duodenum analysis showed that the GG fiber provoked a significant increase (double) in the mucous and submucous layer of the duodenum, while OP and OPG did not produce significant changes in any layer. The large intestine presented the muscular layer significantly reduced in the animals that ingested OP, GG and OPG (27.5%, 38.8% and 62,3%, respectively), while the vilosities only presented significant increase in the animals that received GG and OPG (145.7% and 197.7%, respectively). The other layers (mucous and submucous) did not suffer significant changes in the presence of the worked fibers. In conclusion, the antiallergenic effects of GG and OPG fibers are due to synergistic effects among local mechanic action, increase of mucous protection factors (mucus, prostaglandin and somatostatin) and reduction of the mucous aggressive factor (hydrochloric acid)

ASSUNTO(S)

ulcera gastrica rato fibras

ACESSO AO ARTIGO

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