Unpolished Thai Rice Prevents Aberrant Crypt Foci Formation through the Invovement of ?catenin and COX2 Expression in AzoxymethaneTreated Rats

Colorectal cancer (CRC) is a major cause of morbidity and mortality throughout the world, with chronic inflammation and diet as major causes in its development. Chemopreventive effects of natural dietary products have been the focus of studies for prevention over the past decade. This study was conducted to determine the effects of unpolished Thai rice during precancerous stage through the involvement of ?catenin, cyclooxygenase2 (COX2) expression and inflammatory cytokines focusing on azoxymethane (AOM)induced aberrant crypt foci (ACF)related to CRC. Male Sprague Dawley rats received two injections of AOM (15 mg/kg body weight) at weeks 4 and 5 while rats were treated with 20% or 70% unpolished Thai rice. The rats were sacrificed at week 38 and the colons removed for aberrant crypt foci (ACF) identification. Histopathologic changes, immunohistochemical analysis of ?catenin and COX2 expression, and cytokine expression of proinflammatory and antiinflammatory markers were determined. The administration of unpolished Thai rice significantly and dose dependently decreased the total number of ACF and the percentages of ACF with highgrade dysplasia. Interestingly, unpolished Thai rice suppressed the expression of βcatenin and COX2. In addition, it also altered proinflammatory (IL6 and IFNγ) and antiinflammatory (IL 10) markers. The results suggested that unpolished Thai rice may provide a promising dietary intake for prevention during precancerous stage of CRC development, through the involvement of βcatenin and COX2 expression, and also modulate inflammatory cytokinesrelated to CRC.

Red strain oryza sativa-unpolished thai rice prevents oxidative stress and colorectal aberrant crypt foci formation in rats

Oxidative stress has been proposed to be involved in colorectal cancer development. Many dark pigments of plants have potent oxidative stress preventive properties. In this study, unpolished Thai rice was assessed for antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. Red strain unpolished Thai rice was also administered to rats exposed to azoxymethane (AOM) for induction of aberrant crypt foci (ACF). Serum malondialdehyde (MDA) and ferric reducing antioxidant power (FRAP) were investigated for cellular oxidative stress and serum antioxidants, respectively. Red pigment unpolished Thai rice demonstrated high antioxidant activity and was found to significantly and dose dependently decrease the total density and crypt multiplicity of ACF. Consumption of Thai rice further resulted in high serum antioxidant activity and low MDA cellular oxidative stress. Interestingly, the density of ACF was strongly related to MDA at r=0.964, while it was inversely related with FRAP antioxidants (r=-0.915, p<0.001). The results of this study suggest that the consumption of red strain of unpolished Thai rice may exert potentially beneficial effects on colorectal cancer through decrease in the level of oxidative stress.