How do you process a rat's skull? - briefly
Immerse the specimen in a warm enzymatic detergent solution for several hours, then manually remove remaining tissue with forceps and scalpel. Rinse thoroughly, dehydrate through graded ethanol, clear in xylene, and air‑dry or bake at 60 °C to obtain a clean, hardened skull.
How do you process a rat's skull? - in detail
Processing a rat cranium requires systematic preparation to preserve bone integrity while removing soft tissue and contaminants.
Begin with humane euthanasia following institutional animal‑care guidelines. Immediately immerse the carcass in a 10 % neutral‑buffered formalin solution for 24–48 hours to fix tissues and prevent decomposition. After fixation, rinse the specimen in running water for 10 minutes to remove excess fixative.
Next, excise the skin and musculature surrounding the skull. Use fine scissors or a scalpel to make incisions along the facial planes, then gently peel the skin back with forceps. Dissect away the jaw, tongue, and periosteum, taking care not to fracture the bone.
For complete soft‑tissue removal, place the skull in a 10 % potassium hydroxide (KOH) solution at 55 °C for 12–24 hours. KOH macerates remaining muscle, connective tissue, and cartilage. Periodically agitate the container to promote even digestion. Once the tissue is softened, rinse thoroughly with distilled water.
Degreasing eliminates residual lipids that can obscure bone details. Submerge the skull in a series of ethanol washes (70 % → 95 % → 100 %) for 30 minutes each, followed by immersion in a 1 % sodium hydroxide solution for 15 minutes. Rinse again with distilled water.
Bleaching enhances contrast for skeletal study. Immerse the bone in a 3 % hydrogen peroxide solution for 30 minutes, monitoring until the surface appears uniformly white. Rinse and air‑dry the specimen on a low‑dust rack for 24 hours.
Finally, store the processed skull in a sealed container with silica gel desiccant or in a climate‑controlled cabinet at 20–22 °C and ≤ 50 % relative humidity. Label the container with specimen ID, date of preparation, and chemicals used.
Summary of steps
- Euthanize and fix in 10 % neutral‑buffered formalin (24–48 h).
- Rinse; remove skin and muscles with scalpel and forceps.
- Macerate in 10 % KOH at 55 °C (12–24 h).
- Rinse; degrease through graded ethanol and 1 % NaOH.
- Bleach in 3 % H₂O₂ (30 min).
- Air‑dry (24 h); store with desiccant in controlled environment.
Adhering to this protocol yields a clean, stable rat skull suitable for morphological analysis, imaging, or educational display.