How do you give injections to a rat? - briefly
Place the rat in a restraint device and locate the appropriate site (subcutaneous flank, intraperitoneal abdomen, or tail vein for intravenous). Using a 27–30 G needle, disinfect the area, insert the needle at a shallow angle, and deliver the prescribed volume.
How do you give injections to a rat? - in detail
When an injection is required for a laboratory rat, follow a standardized protocol to ensure accuracy, animal welfare, and reproducibility.
Select appropriate equipment. Use sterile, single‑use syringes (1 mL or 0.5 mL) equipped with needles ranging from 25‑ to 30‑gauge, ½‑ to 1‑inch length, depending on the route and volume. Prepare the formulation under aseptic conditions, filter if necessary, and label with concentration, dose, and time.
Restrain the animal securely but gently. Place the rat in a soft restrainer or hold it by the scruff of the neck with the thumb and forefinger while supporting the body with the other hand. Avoid excessive force that could cause injury or stress.
Determine the injection site:
- Intraperitoneal (IP) – insert the needle at a 30‑45° angle into the lower right quadrant of the abdomen, avoiding the bladder and intestines. Advance until the tip is fully within the peritoneal cavity before delivering the volume (max ≈ 0.5 mL per 100 g body weight).
- Subcutaneous (SC) – lift a fold of loose skin over the dorsal thoracic region, insert the needle bevel‑up at a 10‑15° angle, and inject (max ≈ 0.2 mL per 100 g).
- Intramuscular (IM) – locate the hind‑limb quadriceps or the lumbar paraspinal muscles, insert the needle perpendicular to the muscle surface, and deliver the dose (max ≈ 0.1 mL per 100 g).
- Intravenous (IV) – access the lateral tail vein using a 30‑gauge needle, apply gentle pressure to visualize the vein, insert the needle bevel‑down, and inject the calculated volume (typically ≤ 0.1 mL).
Calculate dosage based on body weight. Weigh the rat, convert the required dose (mg kg⁻¹) to milligrams, then to volume using the solution concentration. Verify the final volume does not exceed the recommended limits for the chosen route.
After injection, withdraw the needle smoothly, apply gentle pressure with a sterile gauze to prevent bleeding, and release the animal back to its cage. Observe for at least 10 minutes for signs of distress, abnormal behavior, or injection site reactions. Record all details—date, time, dose, route, needle size, and any observations—in the animal log.
Maintain compliance with institutional animal care guidelines, ensure all personnel are trained in handling and injection techniques, and keep a clean work area to minimize contamination risk.