title: Arachidonic acid enhances turnover of the dermal skeleton: studies on zebrafish scales.
abstract: In fish nutrition, the ratio between omega-3 and omega-6 poly-unsaturated fatty acids influences skeletal development. Supplementation of fish oils with vegetable oils increases the content of omega-6 fatty acids, such as arachidonic acid in the diet. Arachidonic acid is metabolized by cyclooxygenases to prostaglandin E2, an eicosanoid with effects on bone formation and remodeling. To elucidate effects of poly-unsaturated fatty acids on developing and existing skeletal tissues, zebrafish (Danio rerio) were fed (micro-) diets low and high in arachidonic acid content. Elasmoid scales, dermal skeletal plates, are ideal to study skeletal metabolism in zebrafish and were exploited in the present study. The fatty acid profile resulting from a high arachidonic acid diet induced mild but significant increase in matrix resorption in ontogenetic scales of adult zebrafish. Arachidonic acid affected scale regeneration (following removal of ontogenetic scales): mineral deposition was altered and both gene expression and enzymatic matrix metalloproteinase activity changed towards enhanced osteoclastic activity. Arachidonic acid also clearly stimulates matrix metalloproteinase activity in vitro, which implies that resorptive effects of arachidonic acid are mediated by matrix metalloproteinases. The gene expression profile further suggests that arachidonic acid increases maturation rate of the regenerating scale; in other words, enhances turnover. The zebrafish scale is an excellent model to study how and which fatty acids affect skeletal formation.
authors.affiliation: Department of Organismal Animal Physiology, Radboud University Nijmegen, Nijmegen, The Netherlands ; Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: de Vrieze
authors.affiliation: NIFES (National Institute of Nutrition and Seafood Research), Bergen, Norway.
authors.forename: Mari
authors.initials: M
authors.lastname: Moren
authors.affiliation: Department of Organismal Animal Physiology, Radboud University Nijmegen, Nijmegen, The Netherlands ; Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors.forename: Juriaan R
authors.initials: JR
authors.lastname: Metz
authors.affiliation: Department of Organismal Animal Physiology, Radboud University Nijmegen, Nijmegen, The Netherlands ; Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors.forename: Gert
authors.initials: G
authors.lastname: Flik
authors.affiliation: NIFES (National Institute of Nutrition and Seafood Research), Bergen, Norway.
authors.forename: Kai Kristoffer
authors.initials: KK
authors.lastname: Lie
mesh_terms: D000825:Animal Structures / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D020405:Dermis / Q000187:drug effects / Q000502:physiology*; D015232:Dinoprostone / Q000378:metabolism; D020869:Gene Expression Profiling; D020782:Matrix Metalloproteinases / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D012038:Regeneration / Q000187:drug effects; D015027:Zebrafish / Q000502:physiology*
chemical_list: D016718:Arachidonic Acid; D010758:Phosphorus; D020782:Matrix Metalloproteinases; D015232:Dinoprostone; D002118:Calcium