My First Zebrafish

As you may have guessed, our curriculum at KI involves different labs and methods. Even though they all have their memorable moments, one of the laboratories we worked in the course of Applications of Methods in Toxicological Research that interested me the most is the zebrafish lab. The lab was divided into 2 parts, gene expression and morphology assessment.


To understand the effect of Ah receptors activator and CYP1A inhibitor on CYP1A gene.


Each group has a different exposure. For my group, we have chemical, alpha-naphtoflavone (aNF) and Benzo[a]pyrene (BaP). So we exposed zebrafish embryos into 4 concentrations, negative control, Dimethyl sulfoxide (DMSO), aNF, BaP, and aNF+BaP, for both parts of the lab.


The results of this lab are quite interesting. aNF+BaP showed the highest effect even though logic would have you assume it should have a decrease effect. Because aNF is a CYP1A inhibitor and acts as a partial AHR antagonist while BaP is AHR agonist. So when they are mixed together they should be fighting each other which should cause a decreased result. But instead we got an increased result, leading us to ask the question why? Well after some research we found that many studies have shown that even aNF can acts as a weak AHR agonist or sometime as a partial antagonist in the CYP1A enzymatic activity. The mix concentration would lead aNF to increase the inhibition of CYP1A through metabolized half-life of the AHR agonist BaP and together they would create synergistic action which could lead to a high result.

But to be honest, I think that the highlight of the lab, for me, was the morphology assessment portion. In gene expression, after we purify RNA and synthesizing cDNA we then run the samples with qRT-PCR. But in 3 days exposure for morphology assessment, using the microscope, I got to see the physical changes in the zebrafish, like non inflated swim bladder and yolk edema.

Morphology Assessment: Control (DMSO) vs. aNF+BaP

Of all the labs, I think the zebrafish lab stuck with me is because I felt that it was more fun and interesting. The zebrafish were cute and quite interactive. I watched as they grew from embryos to larvae and the whole process was exciting. The animal lover in me has always struggled when our labs involve animals. One part of me feels sad that the animals are outside their natural habitat, but the other part of me feels grateful that their sacrifice will benefit many others. At least the long hours I have to put into writing up the lab results make me feel like I share a part of the suffering with my fellow lab animals.


Jennifer Tsai

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