Dechorionation, zebrafish embryo

HAGEDORN M, KLEINHANS F w, WILDT D E and RALL w F (1997b) Chill sensitivity and cryoprotectant permeability of dechorionated zebrafish embryos, Brachydanio rerio. Cryobiology, 34, 251-263. 

There is evidence that the chorion may reduce exposure of zebrafish embryos to some compounds (31), and the environmental conditions in which embryos are grown may affect chorion permeability (32). However, the degree to which the chorion serves as a barrier to chemical exposure is controversial and poorly understood. Some have concluded that the effects are too small to justify the efforts of dechorionation (5). Dechorionation removes the possibility of decreased exposure to chemicals in the embryo medium, but damage to the embryos can sometimes result. It is, therefore, important to ensure that removal is done with as much care as possible. 

If dechorionated embryos are cultured, some background reduction in viability and dysmorphology may be avoided by using multiwall plates that are not tissue culture treated. Tissue culture treated plates are designed to promote cell adhesion in cell culture, but this may cause the early stage zebrafish embryo to adhere to the plate with detrimental consequences. 

Mizell, M. and E.S. Romig. The aquatic vertebrate embryo as a sentinel for toxins zebrafish embryo dechorionation and perivitelline space microinjection. Int. J. Dev. Biol. 41 411-423, 1997. 

Eix in a large volume (for this and subsequent procedures up to the hybridization step, use an excess, e.g., 20-fold by volume, of solution over embryo tissue) of MEMEA fix at 4°C for 4h-ovemight. Tissue can be stored at this point for a week. It is convenient to dechorionate zebrafish after fixation. 

ZHANG T and RAWSON D M (1998) Permeabihty of dechorionated one-cell and six-somite stage zebrafish (Brachydanio rerio) embryos to water and methanol. Cryobiology, 37,13-21. 

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