How can you collect urine from a rat? - briefly
Place the rat in a metabolic cage fitted with a collection funnel or a sterile receptacle that gathers voided urine while the animal remains unrestrained. For immediate sampling, gently restrain the rat and insert a sterile catheter into the urethra to aspirate bladder contents.
How can you collect urine from a rat? - in detail
Collecting urine from a laboratory rat requires a controlled environment, appropriate equipment, and adherence to ethical standards. The procedure can be divided into preparation, sampling, and post‑collection handling.
Begin by obtaining institutional approval and ensuring that all personnel are trained in animal welfare. Use a clean, dedicated room with a stable temperature (20‑22 °C) and low ambient noise to minimize stress. Provide the animal with food and water ad libitum until the moment of sampling.
Select a method based on experimental goals:
- Metabolic cage – a sealed housing unit with a sloped floor and a collection funnel. Place the rat in the cage for 24 h; urine drains into a pre‑cooled container. Flush the system with distilled water between animals to avoid cross‑contamination.
- Bladder catheterization – insert a sterile polyethylene catheter (PE‑10 or PE‑50) into the bladder under brief anesthesia (isoflurane 1–2 %). Secure the catheter, allow urine to flow into a chilled tube, then withdraw the catheter and close the incision with sutures or tissue adhesive.
- Urine‑absorbing pad – line the cage floor with a sterile, non‑absorbent pad (e.g., polypropylene). After a defined interval, lift the pad and squeeze urine into a collection tube. This method suits short‑term sampling when metabolic cages are unavailable.
- Spontaneous voiding – place the rat on a clean glass plate; when the animal urinates, collect the droplet with a calibrated pipette. This approach yields small volumes and is useful for pilot studies.
For each technique, follow these steps:
- Sterilize all instruments (autoclave or soak in 70 % ethanol, then rinse with sterile saline).
- Pre‑chill collection vessels (4 °C) to preserve metabolites.
- Record the time of collection and the animal’s identification.
- Measure volume with a calibrated micropipette or analytical balance.
- Transfer urine to labeled microcentrifuge tubes; add protease inhibitors if needed.
- Store samples at –80 °C until analysis.
After sampling, monitor the rat for recovery, especially if anesthesia or catheterization was performed. Return the animal to its home cage once normal behavior resumes. Clean and disinfect all equipment before the next use.