Exposure to benzidine caused apoptosis and malformation of telencephalon region in zebrafish

Abstract

Exposure to benzidine has been known to induce human cancers, particularly bladder carcinomas. In this study, the zebrafish model was used to investigate the developmental toxicity of benzidine. Embryos at 6 h postfertilization (hpf) that were exposed to benzidine exhibited embryonic death in a dose- and time-dependent manner. Benzidine induced malformations in zebrafish, such as small brain development, shorter axes, and a slight pericardial edema. High concentrations (50, 100, and 200 µM) of benzidine triggered widespread apoptosis in the brain and dorsal neurons, as evidenced by acridine orange and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays. Real-time polymerase chain reaction analysis also showed that benzidine treatment affected p53, bax, and noxa expression. Decreases in specific brain markers, such as emx1 in the telencephalon, ngn1 in differentiated neurons, and otx2 in the midbrain, were observed in benzidine-treated embryos at 24 hpf. Conversely, no overt changes to pax2.1 expression in the midbrain-hindbrain boundary were found. Moreover, the use of Tg(HuC:GFP) zebrafish showed that benzidine caused a malformation of the telencephalon region. Our findings show that benzidine exposure triggers widespread apoptosis in the zebrafish brain and dorsal neurons, resulting in the development of an abnormal telencephalon.

Alteration of Diazinon-Induced pmaip1, gstm1, cyp1a1, and diras3 Gene Expression Levels in MRC-5/Human Lung Fibroblast Cell Line by Sambucus ebulus (L)

“…These results show that diazinon is not a potent inducer of pmaip1. Contrary to our results, previous studies demonstrated that exposure to agricultural pesticides such as paraquat (a kind of herbicide) resulted in the elevation of apoptotic markers such as pmaip1 (20). As observed for MRC-5 cells exposed to diazinon, the cyp1a1 mRNA levels were induced by a mixture of 50 µM of diazinon and 20 or 80 µg/mL of the extract by 1.96 and 1.92 folds, respectively.…”

Expression pattern and transcriptional regulatory mechanism of noxa gene in grass carp (Ctenopharyngodon idella)

“…In mammalians, Noxa protein plays an important role in apoptosis induced by mammalian reovirus [16,17]. In zebrafish, Noxa protein was a key mediator of apoptosis in both embryogenesis and adult [18,19]. When the embryos of zebrafish were injected with artificial noxa mRNA, cell apoptosis was observed and the apoptosis was dose-dependent [12].…”

Detection of Medium-Sized Polycyclic Aromatic Hydrocarbons via Fluorescence Energy Transfer

“…These energy transfer efficiencies were particularly efficient for pyrene and benzo[ a ]pyrene, as well as for highly toxic aromatic amines such as 2-aminofluorene (23), 2-acetylaminofluorene (23), and benzidine (24), in combination with fluorophores 10 and 11 . Attempts to extend this cyclodextrin-promoted energy transfer to analytes 4–9 resulted in highly efficient energy transfer in several cases (Table 1), in particular for analytes 4 , 6 , and 8 in combination with fluorophore 10 (Figure 3).…”