Efeitos funcionais da Yacon (Smallanthus sonchifolius) e do Kefir isolados ou associados em ratos com câncer de cólon

Abstract

Colorectal cancer (CRC) is one of the most common malignancies and represents a public health problem due to its important frequency and mortality. The modulation of intestinal health through the administration of pro and prebiotics may be a viable alternative to reduce the risk of colon cancer development. Kefir is a fermented drink, easily digested by the gut, rich in natural probiotics. Yacon (Smallanthus sonchifolius) is a tuberous root rich in fructooligosaccharides (FOS), which have prebiotic properties. The aim of this study was to evaluate the functional effects of yacon and kefir isolated or associated in rats with colon cancer. Adult Wistar rats (n=60) were divided into five groups: C (healthy control fed with AIN-93 M), T (induced to CRC and fed with AIN-93 M), Y (induced to CRC and fed with AIN-93 M and yacon in sufficient quantities to provide 5% FOS), K (CRC-induced and Fed AIN-93 M and with 1 mL kefir mixed with standard diet AIN-93 M) and YK (CRC-induced and fed With AIN-93 M and yacon/kefir combination). Carcinogenesis was induced in groups T, Y, K and YK, with 1,2-dimethylhydrazine (55 mg/kg, subcutaneous, weekly), for five consecutive weeks. During induction, all groups received a standard Diet AIN-93 M. In the 6th to 15th weeks, the experimental groups were fed their respective diets. At the end of the 10th week, four animals from each group were euthanized to collect data referring to the preneoplastic period. The remaining animals were kept in the study until the end of the 15th week period, in which intestinal permeability was performed by collecting 24 h urine after administration of lactulose (100 mg/kg) and mannitol (50 mg/kg). Then, the animals were euthanized and blood collected for analysis of the pro- and anti-inflammatory cytokine profile and total antioxidant capacity (TAC); contents of the large intestine for analysis of intraluminal pH, shortchain fatty acids (SCFA), secretory immunoglobulin A (sIgA), and macro and microscopic lesions of the colorectal mucosa. Kefir: reduced IL-6 and increased lactulose and acetic acid; Yacon: reduced intraluminal and IL-6 pH, and increased sIgA, TAC and butyric acid; Yacon+Kefir: reduced intraluminal pH and IL-6, and increased sIgA, TAC, acetic acid, aberrant crypt focus (ACF) < 3 and total ACF. The results of the study suggest that the consumption of yacon and kefir, yacon+kefir did not reduce the risk and/or progression of colorectal cancer in colorectal cancerinduced animals in a 15-week experiment and yacon+kefir had no symbiotic action.