Development of a Whole-organism Model to Screen New Compounds for Sun Protection

Abstract

We used zebrafish as a whole-organism model to screen new compounds for sun protection activity. First of all, we designed a series of UVB exposure experiments and recorded the phenotypic changes of zebrafish embryos. Results showed that 100 mJ/cm(2) of UVB given six times separated by 30 min intervals is the best condition. Fin malformation (reduced and/or absent fin) phenotypes are the most evident consequences after exposure to UVB. Each fin was affected by UVB, including pelvic, ventral, caudal, and dorsal fin, but pelvic fin seemed to be the most sensitive target after UVB exposure. We furthermore carried out "prevention" and "treatment" experiments using green tea extract and/or (-)-epigallocatechin (EGCG) to test this whole-organism model by observing the morphological changes of all fins (especially pelvic fin) after UVB exposure. Effects of UVB, green tea extract and EGCG on fin development were assessed using the Kaplan-Meier analysis, log-rank test and Cox proportional hazards regression. Results showed that a zebrafish pelvic fin in the UVB + green tea (treatment) group is 5.51 (range from 2.39 to 14.90) times, one in the UVB + green tea (prevention) group is 7.04 (range from 3.11 to 18.92) times, and one in the 25 ppm of EGCG (prevention) group is 22.19 (range from 9.40 to 61.50) times more likely to return to normal fin than one in the UVB only group. On the basis of these observations, we believe this model is effective for screening the higher stability and lower toxicity of new compounds, such as small chemicals which are derivative from EGCG or other dietary agents for sun protection.

Xenobiotic-induced changes in the arginase activity of zebrafish (Danio rerio) eleutheroembryo

“…The morphological effects described in our experiments have also been reported in other teleost species exposed to physical agents such as ultraviolet radiation [34] and chemical agents that cause developmental abnormalities [35]. Furthermore, in our bioassays, otolith size was included as an additional morphometric parameter, and the area of the otoliths was observed to be significantly smaller in eleutheroembryos exposed to the reference toxicant.…”

Essential roles of basic helix-loop-helix transcription factors, Capsulin and Musculin, during craniofacial myogenesis of zebrafish

“…Each assay was run on an Applied Biosystems 7300 Real-Time PCR system in triplicates and expression fold-changes were derived using the comparative C T method (https://products.appliedbiosystems.com). Wang et al [28,29] described the procedures of quantitative PCR. capsulin and musculin were selected as targets (Supplementary Table S1).…”

Transgenic expression of prothymosin alpha on zebrafish epidermal cells promotes proliferation and attenuates UVB-induced apoptosis

“…Around 25 lg of total RNA from each group were used for cDNA synthesis; 1% of cDNA was used for each quantitative PCR reaction. Wang et al (2009) described the procedures of quantitative PCR. An anti-apoptotic gene, bcl2 and two p53-induced apoptosis pathway-related genes, p53 and p21, were selected as targets (Table 1).…”

“…The procedures for UVB exposure and terminal deoxynucleotidyl transferase [TdT]-mediated deoxyuridinetriphosphate [dUTP] nick end labeling (TUN-EL) assay were described previously (Chen et al 2009b;Wang et al 2009) and were conducted in this study with minor modifications. In brief, fifty embryos derived from both WT and Tg(k18:Ptmaa-RFP) were collected at 3 dpf, and exposed to 302 nm 4 doses of UVB irradiation which were generated by a UV crosslinker (Spectroline).…”