National Chiayi University, Taiwan
Title: Retinoic Acid Protects Zebra fish Retinal Photoreceptor Cells from the toxicity of Paclobutrazol
Biography: Wen‐Der Wang
Paclobutrazol (P BZ), a fungicide and plant growth retardant, shows toxicity to aquatic embryos, probably through rain‐wash. Here, we show the toxic effect of PBZ on eye development in zebra fish, as well as the role of the vitamin A metabolite, retinoic acid (RA), controls proliferation an d differentiation of retinal photoreceptor cells, in PBZ toxicity. Embryos were expose d to PBZ with or without RA from 2 to 72 h post‐fertilization (hpf), and PBZ‐treat d embryos (2‐72 hpf) were exposed to RA for additional hours until 120 hpf. Eye size and histology were examined. Examination of the expression levels of gnat1 (rod photoreceptor marker), gnat2 (cone photo receptor marker), aldehyde dehydrogenases (encoding key enzymes for RA synthesis), and phospho‐histone H3 (an M‐phase marker) in the eyes of control and treated embryos were examined and the results indicated that PBZ exposure dramatically reduces photo receptor proliferation, thus resulting in a thinning of the photoreceptor cell layer and leading to a small eye. Co‐treatment of PBZ with RA, or post‐treatment of PBZ‐treated embryos with RA, partially rescues photoreceptor cells, revealed by expression levels of marker proteins and by retinal cell proliferation. PBZ has strong embryonic toxicity to retinal photoreceptors, probably via suppressing the production of RA, with effects including impaired retinal cell division.