Evaluation of the structure-activity relationship of flavonoids as antioxidants and toxicants of zebrafish larvae

[[abstract]]The antioxidant ability of an array of commercially available flavonoids was evaluated on the larvae of the zebrafish model organism, in order to find flavonoids with lower toxicities and higher radical oxygen-scavenging properties than flavone. Among the flavonoids tested, chrysin and morin possessed higher reactive oxygen species (ROS)-scavenging rates (−99% and −101%, respectively) and lower toxicity (LD50 ＞ 100 ppm). Zebrafish fins in the UVB + chrysin group were 6.30 times more likely to grow to normal fin size than those in the UVB-only control group, while zebrafish fins in the UVB + morin group were 11.9 times more likely to grow to normal fin size than those in the UVB-only control group. These results were analysed by the QSAR method and were in accordance with predicted values. A new 4′-fluoroflavone was synthesised. The ROS-scavenging rate of 4′-fluoroflavone was −54%, which corresponds well with the predicted value (−48%). We propose that a combination of QSAR prediction and the zebrafish model organism is efficient for evaluating new flavonoids.[[incitationindex]]SCI[[booktype]]紙

Evaluation of the anti-inflammatory effect of chalcone and chalcone analogues in a zebrafish model

[[abstract]]The aim of this study was to investigate novel chalcones with potent anti-inflammatory activities in vivo. Chalcone and two chalcone analogues (compound 5 and 9) were evaluated using a caudal fin-wounded transgenic zebrafish line “Tg(mpx:gfp)” to visualize the effect of neutrophil recruitment dynamically. Results showed that treatment with compound 9 not only affected wound-induced neutrophil recruitment, but also affected Mpx enzymatic activity. Moreover, protein expression levels of pro-inflammatory factors (Mpx, NFκB, and TNFα) were also regulated by compound 9. Taken together, our results provide in vivo evidence of the anti-inflammatory effects of synthesized chalcone analogues on wound-induced inflammation.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Caffeine treatment disturbs the angiogenesis of zebrafish embryos

[[abstract]]Caffeine is a widely consumed substance that occurs in numerous dietary sources, but teratogenic effects of caffeine intake during embryonic development are still not clear. In the present study, we used the zebrafish as a model to assess caffeine-induced toxicity on embryonic vascular development. A green fluorescent vascular endothelium transgenic line, Tg(fli1:egfp), was utilized for the sensitive detection of vascular development, including vasculo- and angiogenesis. Caffeine-treated embryos showed no defects in vasculogenesis, but revealed dose-dependent (250-350 ppm) developmental defects in intersegmental vessels, dorsal longitudinal anastomotic vessels, and subintestinal vein sprouting. Further, real-time polymerase chain reaction analysis of caffeine-treated embryos showed an upregulation of nrp1a along with a downregulation of sema3aa and sema3c. In conclusion, caffeine treatment induces defects of angiogenesis in zebrafish embryos.[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[countrycodes]]US

Fin reduction is a novel and unexpected teratogenic effect of amikacin-treated zebrafish embryos

[[abstract]]We used zebrafish as a model to assess amikacin-induced embryotoxicity. We exposed zebrafish embryos to amikacin, using different amikacin doses (0-10 ppm), durations (12-48 h), and onsets (0, 24, 48 hpf). Amikacin-induced embryonic toxicity and reduced survival rate were found dependent on the exposure dose, duration and onset. Based on immunostaining with neuron-specific antibodies, amikacin reduced the number and size of zebrafish neuromasts. In addition, Amikacin caused pelvic, dorsal and anal fin defects in dose-dependent and duration-dependent manners. Proliferating cell nuclear antigen immunostaining revealed that amikacin-induced fin defects were not due to reduction of proliferating mesenchymal cells. TUNEL assay demonstrated that amikacin-induced fin defects might not associate with apoptosis. Therefore, further investigations are required to elucidate if other cell death pathways are involved in amikacin-induced fin defects.[[incitationindex]]SCI[[booktype]]紙

Transgenic zebrafish line with over-expression of Hedgehog on the skin: a useful tool to screen Hedgehog-inhibiting compounds

[[abstract]]We generated a transgenic line Tg(k18:shh:RFP) with overexpression of Sonic hedgehog in the skin epidermis. By 5 day-post-fertilization (dpf), many epidermal lesions were clearly observed, including a swollen yolk sac, epidermis growth malformation around the eyes and at the basement of the pectoral fins. Skin histology revealed embryos derived from Tg(k18:shh:RFP) displayed an elevated Nuclear/Cytoplasmic ratio and pleomorphic nuclei compared to their wild type littermates, suggesting the abnormal growth pattern on the epidermis of Tg(k18:shh:RFP) embryos were dysplasia. Later (by 7 dpf), Tg(k18:shh:RFP) embryos displayed broader pectoral fins which are similar to the polydactyly phenotypes of Nevoid basal cell carcinoma syndrome (NBCCS)/Gorlin patients and polydactylous mice. In addition, treatment with cyclopamine is able to enhance and prolong the survival rates and survival durations of Tg(k18:shh:RFP) embryos. In conclusion, this unique Tg(k18:shh:RFP) fish line, should be an excellent experimental animal for screening for a lower toxicity level of the new Hh-inhibitor and can even be used as a new anti-cancer drug-screening platform.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]NL

Rhodamine-ethylenediol, a novel vital fluorescent probe for labeling alkaline phosphatase-rich organelles

[[abstract]]Zebrafish have received considerable attention as an organism-based model in the development of pharmacological agents. Many small moleculesapplied to zebrafish show important behaviours and may constitute new kinds of markers for clinical purposes. Analysis of these molecules can facilitate the development of useful tools for monitoring environmental changes. Many chemicals that are toxic to the environment are known to influence the sensory systems of humans and fish. One important sensory system in all fish is the lateral line organ, which is readily accessible for the assessment of environmental changes. Neuromasts, which are located on the surface of the fish body, are one of the major components of the lateral lines of the zebrafish. Copper enriched water is known to affect the olfactory system in fish. Therefore, small molecules that induce specific patterns in the neuromasts of zebrafish should provide an important animal model with which to explore the effects of environmental changes on the sensory system.Recently, chemical sensors based on the rhodamine skeleton have been designed to specifically detect metal ions, such as Cu(II) and Fe(III)/Hg(II), in zebrafish. However, there has been no report of these rhodamine derivatives used in the specific recognition of the sensory system of zebrafish. Commonly, the sensory system is studied with antibody staining assays of scarified fish. Here, we report that a new rhodamine derivative can be used as a fluorescent chemical probe to visualize the neuromasts and intestinal villi of living zebrafish. Based on the specific recognition of this area in zebrafish, we narrowed the possible enzymes targeted by this rhodamine probe to alkaline phosphatase and confirmed this with a binding assay. It is a well-recognized challenge to develop a fluorescent chemical probe that specifically recognizes a particular enzyme. Furthermore, the transfer of phosphate groups to certain enzymes can activate their catalytic reactivity, triggering a cascade reaction in a signal transduction pathway. The alkaline phosphatase specific recognition by this rhodamine derivative may be applicable to clinical purposes.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙

Safety assessments of chalcone derivatives in a zebrafish model

[[cooperationtype]]國外[[conferencetype]]國際[[iscallforpapers]]Y[[conferencelocation]]Singapor

Embryonic exposure to diclofenac disturbs actin organization and leads to myofibril misalignment

100學年度研究獎補助論文[[abstract]]The objective of this study was to investigate the embryotoxicity of diclofenac. Zebrafish (Danio rerio) embryos at 12 hpf were treated with different dosages of diclofenac (0–2,000 ppm) for different time courses (12–72 hr). Results showed no evident differences in survival rates or morphological changes between the mock-treated control (0 ppm) zebrafish embryos and those with 1-ppm diclofenac-exposure (12–24, 12–36 hpf). In contrast, after higher doses (5 and 10 ppm) of exposure, embryos displayed some defective phenotypes, including malformed somite boundary, a twisted body axis, and shorter body length. In addition, diclofenac-treated embryos exhibited significantly reduced frequencies of spontaneous in-chorion contractions in comparison with mock-control littermates (mock-control: 13.20±2.24 vs. 5–10 ppm diclofenac: 6.66±1.35–3.03±1.84). Subtle changes were easily observed by staining with specific monoclonal antibodies F59 and phalloidin to detect morphological changes in muscle fibers and formation of F-actin, respectively. Our data show that diclofenac treatment disturbs actin organization and muscle fiber alignment, thus causing malformed somite phenotypes.[[incitationindex]]SCI[[booktype]]紙

Nephrotoxicity assessments of acetaminophen during zebrafish embryogenesis

99學年度溫啟仲升等參考著作[[abstract]]We used a green fluorescent kidney line, Tg(wt1b:GFP), as a model to access the acetaminophen (AAP)-induced nephrotoxicity dynamically. Zebrafish (Danio rerio) embryos at different developmental stages (12–60 hpf) were treated with different dosages of AAP (0–45 mM) for different time courses (12–60 h). Results showed that zebrafish embryos exhibited no evident differences in survival rates and morphological changes between the mock-treated control (0 mM) and 2.25 mM AAP-exposure (12–72 hpf) groups. In contrast, after higher doses (22.5 and 45 mM) of exposure, embryos displayed malformed kidney phenotypes, such as curved, cystic pronephric tube, pronephric duct, and a cystic and atrophic glomerulus. The percentages of embryos with malformed kidney phenotypes increased as the exposure dosages of AAP increased. Interestingly, under the same exposure time course (12 h) and dose (22.5 mM), embryos displayed higher percentages of severe defects at earlier developmental stage of exposure (12–24 hpf), whereas embryos displayed higher percentages of mild defects at later exposure (60–72 hpf). With an exposure time course less than 24 h of 45 mM AAP, no embryo survived by the developmental stage of 72 hpf. These results indicated that AAP-induced nephrotoxicity depended on the exposure dose, time course and developmental stages. Immunohistochemical experiments showed that the cells' morphologies of the pronephric tube, pronephric duct and glomerulus were disrupted by AAP, and consequently caused cell death. Real-time RT-PCR revealed embryos after AAP treatment decreased the expression of cox2 and bcl2, but increased p53 expression. In conclusion, AAP-induced defects on glomerulus, pronephric tube and pronephric duct could be easily and dynamically observed in vivo during kidney development in this present model.[[abstract]]對於具共變量誤差之存活資料，假設給定測量共變量，真實共變量之條件分佈已知下，本文研究柯斯正比風險模型的半母數最大概然估計。我們證明了回歸係數估計的漸進常態性和有效性，剖面概似函數的微分可為其共變異矩陣之一致性估計，以及概然函數比檢定的漸進卡方性。我們也對於半母數最大概然估計及剖面概似函數的計算提出一高效的演算法。模擬試驗成功說明了所提估計方法的數值表現。[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]紙本[[countrycodes]]US

UV-induced fin damage in zebrafish as a system for evaluating the chemopreventive potential of broccoli and cauliflower extracts

100學年度研究獎補助論文[[abstract]]This study applied broccoli and cauliflower extracts (whole, floret, and stem) to zebrafish larvae in parallel to receive 100 mJ/cm2 of UVB six times, and recorded their fin malformation phenotypes. Chemopreventive effects of each group, including UVB, whole-, floret-, and stem-extracts of broccoli and cauliflower on fin development were evaluated using Kaplan-Meier analysis, log-rank test, and Cox proportional hazards regression. Results showed that (1) zebrafish fins in the UVB + whole broccoli extract group are 6.20~9.32-times more likely to return to normal fins than ones in the UVB only group, but fins in the UVB + whole cauliflower extract group are only 5.13~11.10-times more likely to recover, indicated that whole broccoli and cauliflower extract had similar chemopreventive ability on fin development; and (2) the broccoli stem has the highest antioxidant capacity among other groups. In conclusion, zebrafish can be used as a system for evaluating the efficacy of other UVB protective compounds.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]US