Establish and use of an epilepsy model in larval zebrafish / 药学学报

Epilepsy is a kind of neurogenic diseases with high prevalence and characterized by seizure, brain paradoxical discharge and convulsion in spontaneous, transient, recurrent and uncontrolled manner. Development of new anti-epilepsy drugs requires a new reliable and high-performance animal models in screening of leading compounds. In this study, an epilepsy model in larval zebrafish was established using pentylenetetrazole (PTZ) compound. The results show that PTZ induced epilepsy-like seizure behavior such as irregular circular swimming, exciting locomotion, high swim velocity and convulsion in zebrafish. Expression patterns of two epilepsy-related gene c-fos and lgi1 were analyzed using RT-PCR and in situ hybridization; c-fos was enhanced and extended and lgi1 expression was reduced in PTZ concentration-dependent in the larval brain. When the model larvae exposed to anticonvulsant valproate (VPA), the epilepsy-like symptom decreased or disappeared, the marker genes c-fos and lgi1, as well as NeuN protein recovered to the normal levels. These responses to PTZ and to antiepileptic drug VPA are consistent with the observations in clinical studies and mouse models. Using this model, we evaluated anti-epilepsy activity of compounds Y53 and BMT, two homolog of berberine. The results show that the model larvae seizure triggered by lighting was partly remedied by Y53; and the larval exciting locomotion under the condition of no stimulation was suppressed by BMT. The findings indicate that the zebrafish larval epilepsy model is able to distinguish compounds with different activities in eleptiform seizure. We conclude that the zebrafish epilepsy model may be as a reliable and useful platform in screening of new anti-epilepsy candidates, which is suitable for basic research in epilepsy pathogenesis.

Effect of beclin1 on vincristine-induced dopaminergic neurons injury in zebrafish / 药学学报

To investigate vincristine-induced dopaminergic neurons toxicity and mechanism, and explore the molecular target to reduce the toxicity, zebrafish was chosen as a model animal, based on RT-PCR, Western blotting, whole mount in situ immunofluorescence and other technical means. The results showed that the transcription levels of tyrosine hydroxylase gene and dopamine transporter protein gene were inhibited. Furthermore, the number of dopaminergic neurons was decreased by vincristine. Autophagy was suppressed and beclin1 gene expression was inhibited in a dose-dependent manner by vincristine in larval zebrafish. Up-regulated beclin1 partly reduced vincristine-induced neurotoxicity, and down-regulated beclin1 increased toxicity. Beclin1 plays an important role in vincristine-induced dopaminergic neurons toxicity.

Teratogenesis and gene targets of 17alpha-ethynylestradiol on embryonic development in zebrafish / 药学学报

The pharmaceutical ethynylestradiol (EE) is a potent endocrine modulator. Application enlargement of ethynylestradiol in clinics and abuse in livestock farming and fishing make it important to explore ethynylestradiol toxicological action on vertebrate embryonic development and to establish an in vivo method for EE toxicity detection efficiently and conveniently. In the present study, using a model animal zebrafish and 17alpha-ethynylestradiol as a representative compound, we have investigated EE2 teratogenicity, target tissues and target genes on zebrafish embryo. The results show that median teratogenesis concentration (TC50) of EE2 is 0.8 microg x mL(-1), and median lethal dose (LD50) is 3.3 microg x mL(-1). Targets of EE2 action were implicated in brain, eyes, heart, muscle, skeleton, pigment and viscera. Embryonic cardiac arrhythmia caused by EE2 is probably resulted from heart abnormal structure. The embryonic stage sensitive to EE2 mainly started at cleavage and last up to the organogenesis with time-accumulating effect. RT-PCR results indicate that EE2 treatment disturbed gene expression pattern at the early period of zebrafish embryonic development by suppressing transcription of gene boz that promotes brain development, upregulating genes for trunk and tail, such as ntl, spt, shh, and perturbing Nodal signal expression of TGFbeta superfamily, for example, cyc, sqt and oep. Using zebrafish, an efficient in vivo method for quick evaluation of EE toxicity on embryonic development has been developed.

Zebrafish model for the study on drug ototoxicity of aminoglycoside antibiotics / 药学学报

Aminoglycoside antibiotics, due to their strong antibacterial effects and broad antimicrobial spectra, have been very commonly used in clinical practice in the past half century. However, aminoglycoside antibiotics manifest severe ototoxicity and nephrotoxicity, and are one of top factors in hearing loss. In this study, three members of the aminoglycoside antibiotics family, gentamycin, neomycin and streptomycin, were chosen as the representatives to be investigated for their toxicity to the embryonic development and the larva hair cells in zebrafish, and also to their target genes associated with hearing-related genes. The results showed that: (1) the lethal effect of all three drugs demonstrated a significant dependence on concentration, and the severity order of the lethal effect was streptomycin > neomycin > gentamycin; (2) all the three drugs caused the larva trunk bending in resting state at 5 dpf (day past fertilization), probably due to their ototoxicity in the physical imbalance and postural abnormalities; (3) impairment and reducing of the hair cells were observed in all three cases of drug treatment; (4) four genes, eya1, val, otx2 and dlx6a, which play an important role in the development of hearing organs, showed differential and significant decrease of gene expression in a drug concentration-dependent manner. This study for the first time reports the relevance between the expression of hearing genes and the three ototoxic antibiotics and also proved the feasibility of establishing a simple, accurate, intuitive and fast model with zebrafish for the detection of drug ototoxicity.