OBJECTIVETo observe the effects of astragalosides on content of rat liver microsomal cytochrome P450 (CYP450), activity of glutathione-S-transferase (GST) and dimethylhydrazine (DMH)-induced aberrant crypt foci formation in rats.

METHODSForty SD rats were randomly and equally divided into control group, Astragalus group, DMH group, Astragalus+DMH group. The animals were killed by off neck and the colorectal and liver tissues taken after treatment with astragalosides and dimethyl hydrazine . The colorectal tissues were stained by methylene blue, ACFs observed and counted, and liver microsomes isolated by differential centrifugation. The total enzyme content was detected by using differential spectrometry for carbon monoxide reduction. The glutathione (GSH) level was detected by using spectrophotometry to reflect the activity of the GST.

RESULTSThe numbers of ACF and large ACF in Astragalus+DMH group were more significantly decreased than the DMH group (P<0.05). Compared with the control group, Astragalus group and Astragalus+DMH group, CYP450 level was decreased significantly, and GST activity increased significantly in DMH group (P<0.05).

CONCLUSIONAstragalosides might reduce the number of colorectal aberrant crypt foci induced by dimethylhydrazine possibly by reducing the content of hepatic CYP450 and increasing GST activity in rats.

Aberrant Crypt Foci ; metabolism ; Animals ; Colorectal Neoplasms ; Dimethylhydrazines ; toxicity ; Male ; Microsomes, Liver ; drug effects ; enzymology ; metabolism ; Rats ; Rats, Sprague-Dawley ; Saponins ; pharmacology

Triptolide, a diterpenoid triepoxide from the traditional Chinese medicinal herb Tripterygium wilfordii Hook. f., is a potential treatment for autoimmune diseases as well a possible anti-tumor agent. It inhibits proliferation of coloretal cancer cells in vitro and in vivo. In this study, its ability to block progress of colitis to colon cancer, and its molecular mechanism of action are investigated. A mouse model for colitis-induced colorectal cancer was used to test the effect of triptolide on cancer progression. Treatment of mice with triptolide decreased the incidence of colon cancer formation, and increased survival rate. Moreover, triptolide decreased the incidence of tumors in nude mice inoculated with cultured colon cancer cells dose-dependently. In vitro, triptolide inhibited the proliferation, migration and colony formation of colon cancer cells. Secretion of IL6 and levels of JAK1, IL6R and phosphorylated STAT3 were all reduced by triptolide treatment. Triptolide prohibited Rac1 activity and blocked cyclin D1 and CDK4 expression, leading to G1 arrest. Triptolide interrupted the IL6R-JAK/STAT pathway that is crucial for cell proliferation, survival, and inflammation. This suggests that triptolide might be a candidate for prevention of colitis induced colon cancer because it reduces inflammation and prevents tumor formation and development.
Animals ; Cell Transformation, Neoplastic/*drug effects ; Colitis/complications ; Colonic Neoplasms/chemically induced/*drug therapy/metabolism/pathology ; Dextran Sulfate/toxicity ; Dimethylhydrazines/toxicity ; Diterpenes/*administration & dosage ; Epoxy Compounds/administration & dosage ; Humans ; Interleukin-6/biosynthesis ; Janus Kinases/metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred ICR ; Mice, Nude ; Neoplasm Transplantation ; Phenanthrenes/*administration & dosage ; STAT3 Transcription Factor/metabolism ; Signal Transduction/*drug effects ; Tumor Burden/drug effects ; rac1 GTP-Binding Protein/*biosynthesis

Prebiotics modulate microbial composition and ensure a healthy gastrointestinal tract environment that can prevent colon cancer development. These natural dietary compounds are therefore potential chemopreventive agents. Thirty Sprague-Dawley rats (4 months old) were experimentally treated with procarcinogen dimethylhydrazine to induce colon cancer development. The rats were randomly assigned to three groups: a control group (CG), a group treated with dimethylhydrazine (DMH), and a group given DMH and inulin, a prebiotic (DMH+PRE). The effects of inulin on the activities of bacterial glycolytic enzymes, short-chain fatty acids, coliform and lactobacilli counts, cytokine levels, and cyclooxygenase-2 (COX-2) and transcription nuclear factor kappa beta (NFkappaB) immunoreactivity were measured. Inulin significantly decreased coliform counts (p < 0.01), increased lactobacilli counts (p < 0.001), and decreased the activity of beta-glucuronidase (p < 0.01). Butyric and propionic concentrations were decreased in the DMH group. Inulin increased its concentration that had been reduced by DMH. Inulin decreased the numbers of COX-2- and NFkappaB-positive cells in the tunica mucosae and tela submucosae of the colon. The expression of IL-2, TNFalpha, and IL-10 was also diminished. This 28-week study showed that dietary intake of inulin prevents preneoplastic changes and inflammation that promote colon cancer development.
Animals ; Bacterial Proteins/genetics/metabolism ; Colon/enzymology ; Colonic Neoplasms/chemically induced/*drug therapy/metabolism ; Colony Count, Microbial ; Cyclooxygenase 2/genetics/metabolism ; Cytokines/blood/genetics ; Diet ; Dietary Supplements/analysis ; Dimethylhydrazines/toxicity ; Enterobacteriaceae/drug effects/physiology ; Fatty Acids, Volatile/genetics/metabolism ; Female ; Gene Expression Regulation/drug effects ; Inulin/administration & dosage/*metabolism ; Lactobacillaceae/drug effects/physiology ; Male ; NF-kappa B/genetics/metabolism ; Prebiotics/*analysis ; Rats ; Rats, Sprague-Dawley