Prednisona em ratos jovens e de meia idade : efeitos sobre a motilidade gastrintestinal associados à mastócitos da mucosa

• Autor(a) principal: Lima, Maysa Bruno de
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/2880
• topic: Envelhecimento; Glicocorticoides; Trato gastrintestinal; CNPQ::CIENCIAS BIOLOGICAS; Aging; Glucocorticoids; Gastrointestinal tract

Mast cells are part of the immune system that regulate the homeostasis in the gastrointestinal tract and can be linked to functional gastrointestinal diseases. During the aging process there are a decrease of physiological functions including gastrointestinal and immune disorders. Prednisone is one of the most used drugs for senior people, however there are few studies evaluating its effects. The aim of the study was relate the gastrointestinal motility and intestinal mast cells in young (2 months) and middle-aged (7 months) rats treated with two doses of prednisone. Male Wistar rats (n=38) were divided into two age groups. Each group was subdivided into control animals that received saline 0.9% (n=7); treated animals with 0.625 mg/kg/day of prednisone (n=6) and treated animals with 2,5 mg/kg/day of prednisone (n=6). The treatment was performed by oral route for 15 consecutive days, then the gastrointestinal records, blood samples and intestinal tissue were obtained. The Alternate Current Biosusceptometry through the intake of magnetically labeled chow, evaluated: frequency and amplitude of contraction, mean gastric emptying time (MGET), mean colonic arrival time (MCAT) and mean small intestine transit time (MSITT). Cellular immunity was represented by leucogram and intestinal mucosal mast cells count. The data were correlated (Spearman) and analyzed by ANOVA followed by Tukey test (p <0.05). Prednisone reduced leucocytes, as expected, in young animals compared to the control (p <0.05), although it was not enough to cause immunosuppression in middle-aged animals. The drug caused a decrease in the number of intestinal mast cells in the young group and an increase in the middle-aged group, compared to their controls (p <0.001 and p <0.01 respectively). Still, prednisone increased the frequency of gastric contractions in young animals (p <0.05) causing the opposite effect in middle-aged animals (p <0.05). The higher dose of prednisone accelerated the gastric emptying and slowed the intestinal transit at the young group, while in middle-aged animals the drug slowed the gastric emptying and accelerated the intestinal transit. There was a strong positive correlation between intestinal transit time and the amount of tissue mast cells after the drug administration. Surprisingly, middle-aged animals without any treatment showed a decrease in leukocytes and mast cells (p <0.001), as well as increased frequency of gastric contraction (p <0.02) compared to young group. Therefore, the prednisone appears to potentiate the initial changes due to aging, causing opposite effects. In conclusion, the administration of prednisone causes changes in gastrointestinal motility and the amount of mast cells in both age groups totally different way, and there was a strong positive correlation between the number of mast cells and the transit time through the small intestine.