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Effects of Valproic Acid on the Somitic Development of Danio rerio

Bryan Graye '01 and Jeff Mindel '02
Spring 2001


In previous research it has been established that the chemical valproic acid is a powerful teratogen. Specifically it is known to inhibit the expression of the gene Pax-1 in the somites of chickens, mice, and rats resulting in deformed somites or vertebrae. Since somites are common to all chordates and give rise to similar structures in all of them, we hpothesized that valproic acid would have a similar effect on zebrafish somites. During our experiment we obtained zebrafish embryos during gastrulation and divided them into five experimental groups of about 20-30 embryos each. In addition to a control solution the embryos were placed in solutions that had valproic acid concentrations of 0.2M, 0.1M, 0.05M, and 0.025M. After 24 hours of exposure we performed a whole mount antibody stain for somites using F6, a monoclonal antibody to somite boundaries. All of the embryos in the 0.2M group failed to survive while 16 of 18 survived in the control group. It appears that 0.2M was a lethal concentration. The survival rates in the other groups were inversely proportional to the concentration of valproic acid as the mortality rate of embryos increased to 100% with the increasing dosages of valproic acid from 0.025M to 0.2M. The control group seemed to be farther along in development, and was the only group that had pigment. The 0.025M group did not produce any noticeable deformities, as this was probably not a significant concentration of valproic acid. The embryos in the 0.1M group showed the most visible deformities. There were several instances of kinked tails and what appeared to be crowded somites. These findings imply that there is enough of a similarity in the physiology and development of zebrafish to other chordates that similar results are obtained during valproic acid exposure.


© Cebra-Thomas, 2000

Last Modified: 31 May 2001

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