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USE OF MULTI-PHOTON LASER SCANNING CONFOCAL MICROSCOPY TO DESCRIBE THE TISSUE DISTRIBUTION OF PBTS IN FISH EARLY LIFE STAGES
Hornung, M. W., P. M. Cook, AND J W. Nichols. USE OF MULTI-PHOTON LASER SCANNING CONFOCAL MICROSCOPY TO DESCRIBE THE TISSUE DISTRIBUTION OF PBTS IN FISH EARLY LIFE STAGES. Presented at 2002 SETAC Annual Meeting, Salt Lake City, UT, November 16-20, 2002.
Fish early life stages (ELS) are more sensitive than juveniles or adults to many persistent bioaccumulative toxicants (PBTs). To better understand the mechanisms by which these chemicals produce toxicity during ELS, dose-response relationships need to be determined in relation to the dynamic distribution of chemicals in sensitive tissues. In this study, a multi-photon laser scanning confocal microscope (LSCM) was used to describe chemical distribution in tissues during fish ELS by imaging fluorescent chemicals in situ. The method was tested in Japanese medaka (Oryzias latipes) using pentamethyl-difluoro-boro-indacene (BODIPY), a model chemical having high fluorescence efficiency and a log Kow value near 5.0. Newly fertilized medaka eggs were exposed to BODIPY in embryo rearing media. Embryos and larvae were then observed throughout development. Fluorescent signal was initially very strong in yolk lipid droplets with moderate signal in the yolk. During development the fluorescent signal became distributed throughout the embryo with strong signal remaining in the yolk and yolk lipid droplets. As embryonic development progressed, fluorescence became evident in the gall bladder, bile ducts, and gut. Following hatch, when the lower gastrointestinal tract opened to the environment, a strong signal was observed being eliminated. The tissue distribution of BODIPY during early development was then compared to that of fluoranthene which has a log Kow value of 4.95. Following exposure of newly fertilized medaka eggs, BODIPY and fluoranthene demonstrated similar tissue distribution throughout development. The LSCM is a useful tool to describe the tissue distribution of PBTs during fish ELS. A goal of this effort is to relate this descriptive information to temporal changes in whole body chemical concentrations.
This abstract does not necessarily reflect EPA policy.