Project description:The rat models of colorectal cancer (CRC), such as the azoxymethane (AOM) cancer-inducing model, are important tools for researching cancer initiation pathways. However, there is limited understanding of the expression pathways of underlying normal rat colonic epithelium and how this relates to human colonic epithelium. The aim of this study was to study the acute effects of AOM on the gene and pathway expression of the rat's colonic epithelium, whilst contrasting the background normal global expression patterns along the length of the rat as compared to the normal human colonic epithelium. The study used microarrays to investigate global gene expression of the colonic epithelium from proximal and distal sections of AOM- and saline (normal)-treated Sprague Dawley rats. Rat gene and pathway expression patterns were then compared in-silico with human microarray data (see GSE9254 for files) from normal tissue samples originating from proximal and distal regions of the colon.
Project description:Comparison of global gene expression in the proximal and distal colonic epithelium in azoxymethane treated rats. Keywords: disease state analysis
Project description:Rats were randomly assigned to one of two different groups, a control (C, n=6) group that received a saline enema and a TNBS group (n=6) that received the TNBS challenge. Colonic epithelial cells were isolated from the distal colon of control and TNBS (non necrosed) rats by calcium chelation and percoll purification. Two mRNA samples were obtained from isolated control and TNBS rat colonocytes (pooled from n=6) further characterized with microarrays.
Project description:Dextran sodium sulfate (DSS) causes inflammation in the gut similar to ulcerative colitis in humans. Patients with ulcerative colitis have increased risk of developing colon cancer. We sought to determine which genes are altered in the normal colonic epithelium, and which changes depend on the Pirc mutation. 97 day old (ACIxF344)F1 wild type and Pirc male rats either untreated or given 4% DSS in the drinking water from 40-47 and 54-61 days of age, housed in 12 hour light:12 dark, ad lib feeding. Normal colonic tissue was collected from the distal colon at 97 days of age.
Project description:The rat models of colorectal cancer (CRC), such as the azoxymethane (AOM) cancer-inducing model, are important tools for researching cancer initiation pathways. However, there is limited understanding of the expression pathways of underlying normal rat colonic epithelium and how this relates to human colonic epithelium. The aim of this study was to study the acute effects of AOM on the gene and pathway expression of the rat's colonic epithelium, whilst contrasting the background normal global expression patterns along the length of the rat as compared to the normal human colonic epithelium.
Project description:Dextran sodium sulfate (DSS) causes inflammation in the gut similar to ulcerative colitis in humans. Patients with ulcerative colitis have increased risk of developing colon cancer. We sought to determine whether genes altered in the normal colonic epithelium or tumor differed between sporadic and inflammation-associated tumor development. 97 day old (ACIxF344)F1-Pirc male rats either untreated or given 4% DSS in the drinking water from 40-47 and 54-61 days of age, housed in 12 hour light:12 dark, ad lib feeding and drinking conditions. Normal colonic tissue and tumors were harvested from the distal colon at 97 days of age. A two color, reference design experiment hybridized according to Agilent protocols against a reference pool of RNA made up from colon tissue taken from pooled wild type rats which was labeled with Cy5.
Project description:Comparison of global gene expression in the proximal and distal colonic epithelium in azoxymethane treated rats. Experiment Overall Design: Ten male Sprague Dawley rats weighing approximately 245 ± 14.5 g were housed in wire-bottomed caging in a temperature controlled room (22-24°C) with a 12 h light/dark cycle. They were randomly allocated into two groups (n=5) with approximately equal body weights. They were given free access to water and modified AIN-93G diet for 10 days when they were injected with 15 mg of AOM/kg subcutaneously (Sigma Chemical Co., St. Louis, MO, USA). They were anaesthetised with isoflurane and killed by exsanguination six hours after injection. The large bowel (excluding the rectum) was removed, opened longitudinally along the mesenteric border and digesta removed. The colon was rinsed clean with PBS and transferred to a chilled ceramic plate. The most distal and the most proximal 0.5 cm were discarded. Mucosal samples for gene expression and protein analyses were collected by scraping the next 4 cm of proximal and distal colon with new microscope slides. Experiment Overall Design: The mucosal scraping was transferred into RNAlater (Sigma Chemical Co., St. Louis, MO, USA) and stored at -80oC for later processing. All instruments were replaced or cleaned thoroughly between animals. All procedures involving animals were approved by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Human Nutrition Animal Ethics Committee and complied with the Australian code of practice (2004). Experiment Overall Design: The distal and proximal colonic mucosal samples were removed from the RNAlater stabilisation reagent (Sigma, Australia) and placed in 1ml of TRIzol® Reagent (Invitrogen, Sydney, N.S.W., Australia). Samples were then homogenised using beads (mix of 2.5mm glass and 0.1 - 1.0mm diameter silicon-zirconian beads) in a MiniBeadbeater-8⢠(BioSpec Products Inc. Oklahoma, US). Total RNA was then extracted according to the TRIzol® Reagent manufacturerâs instruction after which samples were further purified using RNAeasy mini spin columns (QIAGEN, Doncaster, Victoria, Australia) with a DNase on-column digestion as per the manufactureâs instructions. The integrity of the RNA was checked using a Bioanalyzer 2100 (Agilent Technologies) and quantified using a NanoDrop® ND-1000 Spectrophotometer. Experiment Overall Design: RNA (4.5ug) samples were processed for Microarray expression analysis using high-density oligonucleotide arrays (Affymetrix® GeneChip array, Affymetrix®, Santa Clara, CA, USA) commensurate with the manufacturerâs instructions.
Project description:Ulcerative colitis (UC), a chronic, nonspecific inflammatory bowel disease characterized by continuous and diffuse inflammatory changes in the colonic mucosa, requires novel treatment method. Photodynamic therapy (PDT), as a promising physico-chemical treatment method, were used to treat UC rats’ model with novel photosensitizer LD4 in this paper, the treatment effect and mechanism was investigated. LD4-PDT could improve the survival rate of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced UC model rats, decrease expression of interleukin (IL)-6, IL-1, tumor necrosis factor (TNF)-α, malondialdehyde (MDA), myeloperoxidase (MPO) and increase the expression of glutathione (GSH) and superoxide oxidase (SOD), while protecting the integrity of the intestinal epithelium. LD4-PDT treatment could rebuild the intestinal microflora composition and reprogram the colonic protein profiles in TNBS-induced rats to almost the normal state. Proteomics analysis based upon TNBS-induced UC model rats revealed that Amine oxidase copper-containing 1 (AOC1) was a potential target of LD4-PDT. Novel photosensitizer agent LD4-PDT represents an efficient treatment method for UC, and AOC1 may be a promising target.
Project description:To examine the effect of melatonin on global gene expression in the colonic epithelium, we used RNA-seq analysis to identify differentially expressed genes (DEGs) in samples from three melatonin-treated (MEL4-6) versus three vehicle-treated pinealectomized rats (VEH1-3) injected i.p. at the beginning of subjective night and sacrificed 4 h later. More than 12 050 expressed genes were identified in each sample out of 18 258 genes in the database. A surprisingly small number of significant DEGs (49) was identified. The GO pathways analysis revealed that the largest group of the DEGs was associated with immune system response. Most DEGs (47) identified by RNA-seq were independently analyzed by RT-qPCR and the correlation between both methods indicates reliability of the data.