Citation:

Hornung, M. W., P. M. Cook, K. M. Flynn, D B. Lothenbach, R. D. Johnson, AND J. W. Nichols. USE OF MULTI-PHOTON LASER-SCANNING MICROSCOPY TO DESCRIBE THE DISTRIBUTION OF XENOBIOTIC CHEMICALS IN FISH EARLY LIFE STAGES. AQUATIC TOXICOLOGY. Elsevier Science BV, Amsterdam, Netherlands, 67(1):1-11, (2004).

Description:

To better understand the mechanisms by which persistent bioaccumulative toxicants (PBTs) produce toxicity during fish early life stages (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 microscope (MPLSM) was used to determine the two-photon excitation spectra of several polyaromatic hydrocarbons (PAHs) and to describe chemical distribution among tissues during fish ELS. Intense fluorescent signal was produced with the model fluorophore, pentamethyl-difluoro-boro-indacene (BODIPY), as well as fluoranthene and benzo[a]pyrene, while pyrene gave very little signal using this system. The method was tested by exposing newly fertilized Japanese medaka (Oryzias latipes) eggs to BODIPY or fluoranthene for 6 h, followed by transfer to clean media. Eggs and larvae were then imaged through five days post-hatch. The two test chemicals partioned similarly throughout development and differences in fluorescence intensity among tissues were evident to a depth of several hundred microns. Initially, the most intense signal was observed in the oil droplet within the yolk, while a moderate signal was seen in the portion of the yolk containing the yolk-platelets. As embroyonic development progressed, the liver biliary system, gall bladder, and intestinal tract accumulated strong fluorescent signal. After hatch, once the gastrointestinal tract was completely developed, most of the fluorescent signal was cleared. The MPLSM is a useful tool to describe the tissue distribution of fluorescent PBTs during fish ELS.

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