Cancer chemopreventive potential of the Egyptian flaxseed oil in a rat colon carcinogenesis bioassay--implications for its mechanism of action.
(19/38)
The possible chemopreventive effects of natural Egyptian flaxseed oil on preneoplasia and cancer formation were investigated in a rat medium-term colon carcinogenesis bioassay. Male Wistar rats were divided into 6 groups. Groups 1, 3 and 5 were initiated by 1,2-dimethylhydrazine (DMH) 20 mg/kg body weight s.c. 8 times, twice a week to initiate colon carcinogenesis. Groups 1 and 3 received 20% or 5% flaxseed oil respectively in diet in post initiation stage until the end. Groups 2 and 4 served as a flaxseed dose corresponding controls without carcinogen initiation, while rats in group 6 served as negative controls. Distribution and total numbers of aberrant crypt foci (ACF), putative preneoplastic lesions, particularly those with >/=4 aberrant crypts (ACs), and the numbers and sizes of colon tumors (adenoma and carcinoma) were significantly decreased by both treatment doses of flaxseeds as compared to group 5. Histochemical investigation revealed that the numbers of mucus-secreting cells in the colonic mucosa were reduced gradually during progression of colon carcinogenesis. Intriguingly, flaxseed oil caused the numbers and integrity of the mucus-secreting cells to retain close to normal levels and in a dose dependent manner. Moreover, the hematological parameters were almost constant between the groups particularly at the dose of 5% as compared to groups 5 and 6. PCNA-labeled indexes (PCNA-LI) in the DMH-initiated colonic mucosa were found to be decreased by both doses of flaxseeds administration. In conclusion, the present study showed that the post initiation dietary administration of flaxseeds oil suppressed DMH-induced colon carcinogenesis in rats without significant side effects. The mechanism is likely to be through its inhibitory effects on early cellular proliferation and modulation of mucin secretion properties in the initiated colonic mucosa. (+info)
P53 gene mutation increases progastrin dependent colonic proliferation and colon cancer formation in mice.
(20/38)
Effect of luteolin on the levels of glycoproteins during azoxymethane-induced colon carcinogenesis in mice.
(21/38)
Luteolin (LUT), a bioflavonoid has been used as a chemopreventive agent world-wide against chemically induced cancer. Hence we designed an experiment to assess chemopreventive action of LUT on lipid peroxidation (LPO) and glycoconjugates in azoxymethane (AOM)-induced colon carcinogenesis. Colon cancer was induced by 15 mg/body kg. body weight of AOM and administration of LUT (at the dose of 1.2 mg/kg. body weight) was till end of the study. Analysis of lipid peroxidative end products such as protein carbonyl (PC), malonadehyde (MDA) and conjucated dienes (CD) demonstrated significant increase in in AOM-induced animals with reduction by LUT (p<0.05) . Increased levels of glycoconjugates such as hexose, hexosamine, sialic acid, fucose and mucoprotein were analyzed in serum and colon tissues examined histopathologically by periodic acid Schiff's (PAS) staining were also reversed by LUT l(p<0.05) . The secondary marker of colon cancer mucin depleted foci (MDF) was assessed in control and experimental group of animals. A characteristic increase of MDF was observed in AOM- induced colon cancer animals. Treatment with LUT decreased the incidence of MDF. These results suggest that LUT alters the expression of glycoconjugates and suppress colon cancer. Hence, we speculate that LUT can be used as a chemopreventive agent to treat colon cancer. (+info)
Red strain oryza sativa-unpolished thai rice prevents oxidative stress and colorectal aberrant crypt foci formation in rats.
(22/38)
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. (+info)
Eicosapentaenoic acid (EPA) efficacy for colorectal aberrant crypt foci (ACF): a double-blind randomized controlled trial.
(23/38)
Pomegranate (Punica granatum) peel extract efficacy as a dietary antioxidant against azoxymethane-induced colon cancer in rat.
(24/38)
Functional foods include antioxidant nutrients which may protect against many human chronic diseases by combating reactive oxygen species (ROS) generation. The purpose of the present study was to investigate the protective effect of pomegranate peel extract (PPE) on azoxymethane (AOM)-induced colon tumors in rats as an in vivo experimental model. Forty Sprague-Dawley rats (4 weeks old) were randomly divided into 4 groups containing 10 rats per group, and were treated with either AOM, PPE, or PPE plus AOM or injected with 0.9% physiological saline solution as a control. At 8 weeks of age, the rats in the AOM and PPE plus AOM groups were injected with 15 mg AOM/kg body weight, once a week for two weeks. After the last AOM injection, the rats were continuously fed ad-libitum their specific diets for another 6 weeks. At the end of the experiment (i.e. at the age of 4 months), all rats were killed and the colon tissues were examined microscopically for lesions suspected of being preneoplastic lesions or tumors as well as for biochemical measurement of oxidative stress indices. The results revealed a lower incidence of aberrant crypt foci in the PPE plus AOM administered group as compared to the AOM group. In addition, PPE blocked the AOM-induced impairment of biochemical indicators of oxidative stress in the examined colonic tissue homogenates. The results suggest that PPE can partially inhibit the development of colonic premalignant lesions in an AOM-induced colorectal carcinogenesis model, by abrogating oxidative stress and improving the redox status of colonic cells. (+info)