How do you dissect a mouse? - briefly
After humane euthanasia, position the animal dorsal side up, secure it with pins, and make a midline skin incision from the abdomen to the thorax. Reflect the skin and underlying muscle, expose the visceral cavity, and harvest the desired organs with fine scissors or forceps.
How do you dissect a mouse? - in detail
The dissection of a laboratory mouse begins with preparation of the work area and equipment. Clean the dissecting surface, arrange a dissecting microscope, forceps, scissors, scalpel, and a set of fine needles. Prepare a solution of appropriate anesthetic (e.g., isoflurane vapor or injectable ketamine‑xylazine) and verify the functionality of the delivery system. Place all waste containers, including sharps and biohazard bins, within easy reach.
Anesthesia is induced according to institutional animal‑care guidelines. Once a surgical plane of anesthesia is confirmed—absence of reflexes, stable respiration—secure the mouse on a ventral side platform. Apply a thin layer of petroleum jelly to the eyes to prevent corneal drying. Perform euthanasia if required by the protocol (e.g., overdose of anesthetic or cervical dislocation) before proceeding to tissue collection.
The following sequence outlines the dissection steps:
- Incision – Using a scalpel, make a midline skin incision from the lower abdomen to the thorax. Extend the cut laterally to expose the underlying musculature.
- Skin retraction – Grasp the skin edges with fine forceps and gently pull apart to reveal the peritoneal cavity.
- Muscle separation – Cut through the abdominal wall muscles with scissors, taking care to avoid damage to internal organs.
- Organ exposure – Locate the liver, stomach, and intestines. If the study requires specific organ retrieval, isolate the target organ with blunt dissection and remove it with forceps.
- Thoracic access – Extend the incision cranially, cut through the rib cage, and remove the sternum to expose the heart and lungs.
- Cardiovascular sampling – Insert a fine needle into the left ventricle to collect blood, or excise the heart for histological analysis.
- Brain extraction – Perform a craniotomy by removing the skull bones with micro‑dissection tools. Gently lift the brain using a spatula, taking care to preserve cortical structures.
- Tissue preservation – Place each harvested tissue in pre‑labeled containers containing fixative (e.g., 4 % paraformaldehyde) or snap‑freeze in liquid nitrogen, depending on downstream applications.
After completion, cleanse all instruments with appropriate disinfectants, dispose of biological waste according to biosafety regulations, and document the procedure, including animal identifier, anesthesia details, and tissue types collected. This systematic approach ensures reproducibility, minimizes tissue damage, and complies with ethical standards for animal research.