The effect of PCB contamination in fish oil on gene expression involved in inflammation and DNA repair enzymes in rat colon (824.4)

Abstract

Experimental data has indicated that fish oil has health implications in preventing colon cancer prevalence through mechanisms involved in inflammation and DNA repair. However, discussions have yet to include possible environmental contaminant variables found in some fish or fish oil. We investigated the effects of polychlorinated biphenyl (PCB, 4000 ng/ml fat) contaminated fish oil supplementation for 9 weeks in order to examine colonic gene expression involving inflammation and DNA repair enzymes by real time PCR in azoxymethane‐treated rats. Non‐contaminated and contaminated fish oil groups down‐regulated cyclooxygenase‐2 (P=0.040) and Rel A expression (p = 0.003) compared to corn oil group. Both fish oil groups up‐regulated transcription of 06‐methylguanine DNA methyltransferase gene, with the non‐contaminated group reporting a larger increase over the PCB contaminated group (P=0.044). These results suggest that dietary fish oil protects against colon cancer by lowering pro‐inflammatory gene levels and elevating DNA repair enzyme gene expression. PCB contaminated fish oil may reduce the beneficial effects of fish oil on colon carcinogenesis. Longer duration and different range of contaminant levels may benefit future studies.Grant Funding Source: Supported by CHNR08‐810, SDSU UGP and NUTR 302L class.