Kidney Flat Mount Preparation: A Procedure to Dissect and Prepare a Flat Mount for Microscopic Analysis of Adult Zebrafish Kidney

To begin, decant away any extra solution from an anesthetized fish and place it on a tissue or paper towel. After removing the head and internal organs, use superfine dissection needles to pin open the body walls. Locate the kidney organ, which is adherent to the dorsal wall of the animal.

Use fine forceps to detach the kidney from the dorsal wall. Gently place the kidney into a 5-milliliter glass vial containing 1x PBS and wash three times for 5 minutes each. Remove the kidney with a transfer pipette and place it onto a clean glass slide with one to two drops of 1x PBS.

Use fine forceps to flatten the kidney on the slide, making sure no tissue has curled or otherwise overturned on itself. A tungsten wire tool can be used to make small incisions in the connective tissue to facilitate the flat positioning of the kidney.

Next, place small pieces of modeling clay on each corner of an 18 by 18 millimeter glass coverslip. Slowly set the coverslip onto the kidney, keeping a slight angle to minimize trapping air bubbles. Add an additional drop of 1x PBS to fill the space between the coverslip and slide if necessary.