Zebrafish (Danio rerio) is an emerging model for the study of physiology. Zebrafish natural environment is poorly ion concentrated fresh water. Gills and kidneys participate in maintaining zebrafish homeostasis but very little is known about ion transports in zebrafish kidneys.
To study ion transport, we use in vitro microperfusion of rodent kidney segments. This week, I tried to dissect and perfuse zebrafish kidney segments and here are the first pics :
3 to 6 month old zebrafish.
Zebrafish were kept in a little tank of fresh poorly ionised water on the lab bench. Room temperature was 29°C during the two days of experiments which was an acceptable temperature for the fish.
Fish were killed in 50 ml of 0,2 % tricaine before dissection. And then placed on a tissue paper under microscope.
The kidney is a flat organ running from the head of the fish (removed here) to the tail of the fish. It forms a dark triangle just behind the swim bladder. I used Gary F. Gerlach, Lauran N. Schrader and Rebecca A. Wingert video on Jove to help me dissecting this fragile organ.
Click here to see there video.
Here is part of the kidney in the dissecting medium (Ringer with BSA). It is difficult to see what is the proximal and what is the distal part of the nephron at this stage. But with the use of thin forceps, it is quite easy to separate different structures.
Long tubules appeared, looking like rodent ones by their size and color. The whole structure of the nephron is different as there are no Henle's loop.
This is an image of one peace of the top nephron held by a glass pipette in a Ringer bath in the chamber of an inverted microscope. I perfused the tubule with blue ringer and the dye clearly escaped rapidly from the tubule meaning this segment might be very leaky. Under perfusion pressure, cells became larger.
