title: Effects of green tea and high-fat diet on arachidonic acid metabolism and aberrant crypt foci formation in an azoxymethane-induced colon carcinogenesis mouse model.
abstract: Excessive fat consumption is a risk factor for colon carcinogenesis, and green tea consumption may reduce the risk of colon and other cancers. The current study was designed to investigate the effects of green tea and a high-fat diet on arachidonic acid metabolism and aberrant crypt foci formation in an azoxymethane (AOM)-induced colon carcinogenesis mouse model. We also determined whether green tea consumption altered the size of regional fat pads. CF-1 female mice were maintained on either a high-fat (20% corn oil) or a low-fat (5% corn oil) diet. AOM was given subcutaneous at a dose of 7.5 mg/kg body weight at 6 wk and then a dose of 10 mg/kg at 7 wk of age. Two weeks after the second AOM injection, 0.6% green tea (6 mg tea solids/ml) was given as the drinking fluid and continued for 10 wk until the experiment was terminated. In the AOM-treated mice not receiving green tea, the high-fat diet significantly enhanced colonic levels of 5-lipoxygenase, leukotriene A4 hydrolase, and leukotriene B4, but it did not significantly alter prostaglandin E2 levels and aberrant crypt foci formation. In AOM-treated mice on the high-fat diet, green tea significantly decreased colonic levels of cytosolic phospholipase A2, 5-lipoxygenase, and leukotriene B4; green tea treatment also decreased the number of aberrant crypt foci (P < 0.05). The weights of parametrial and retroperitoneal fat pads were increased by the high-fat diet and decreased by green tea treatment. The current results indicate that green tea consumption and dietary fat modulate 5-lipoxygenase-dependent pathway of arachidonic acid metabolism during AOM-induced colon carcinogenesis. Green tea inhibits ACF formation in mice on a high corn oil diet, suggesting its possible inhibitory effect on colon carcinogenesis in populations such as those in Western countries that consume high amounts of fat.
authors.affiliation: Graduate Program of Food Science, Rutgers, the State University of New Jersey, New Brunswick, NJ 08854, USA.
authors.forename: Jihyeung
authors.initials: J
authors.lastname: Ju
authors.forename: Yue
authors.initials: Y
authors.lastname: Liu
authors.forename: Jungil
authors.initials: J
authors.lastname: Hong
authors.forename: Mou-Tuan
authors.initials: MT
authors.lastname: Huang
authors.forename: Allan H
authors.initials: AH
authors.lastname: Conney
authors.forename: Chung S
authors.initials: CS
authors.lastname: Yang
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000032:analysis; D016718:Arachidonic Acid / Q000378:metabolism*; D001397:Azoxymethane; D001835:Body Weight; D003106:Colon / Q000737:chemistry / Q000473:pathology*; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D003600:Cytosol / Q000201:enzymology; D004041:Dietary Fats / Q000008:administration & dosage*; D015232:Dinoprostone / Q000032:analysis; D004326:Drinking; D004435:Eating; D004851:Epoxide Hydrolases / Q000032:analysis; D005260:Female; D007975:Leukotriene B4 / Q000032:analysis; D051379:Mice; D009929:Organ Size; D010741:Phospholipases A / Q000032:analysis; D054467:Phospholipases A2; D013662:Tea
chemical_list: D004041:Dietary Fats; D013662:Tea; D007975:Leukotriene B4; D016718:Arachidonic Acid; D001094:Arachidonate 5-Lipoxygenase; D010741:Phospholipases A; D054467:Phospholipases A2; D004851:Epoxide Hydrolases; D015232:Dinoprostone; D001397:Azoxymethane; C043134:leukotriene A4 hydrolase