How to inject furosemide into a rat? - briefly
Prepare a sterile furosemide solution at the required concentration, draw the calculated dose into a 27‑30 G needle, and administer it intraperitoneally with a swift, smooth insertion to minimize tissue trauma. Observe the rat for diuresis and any adverse signs for at least 30 minutes after injection.
How to inject furosemide into a rat? - in detail
Administering furosemide to a laboratory rat requires precise preparation, dosage calculation, and sterile technique.
First, determine the animal’s body weight. Typical dosing ranges from 1 mg kg⁻¹ to 5 mg kg⁻¹, depending on experimental goals. Multiply the chosen dose by the rat’s weight (kg) to obtain the required amount of drug. Dissolve the calculated mass of furosemide in sterile physiological saline (0.9 % NaCl) to achieve a concentration that allows injection volumes of 0.1–0.2 mL per 100 g body weight. Filter the solution through a 0.22 µm membrane to ensure sterility.
Prepare the injection equipment: 1 mL syringes with 27‑30 G needles for intraperitoneal (IP) delivery, or 30‑33 G needles for subcutaneous (SC) administration. For intravenous (IV) injection, use a catheterized tail vein and a 30‑G needle.
Aseptic handling steps:
- Wear gloves, lab coat, and eye protection.
- Disinfect the injection site with 70 % ethanol and allow it to dry.
- Load the calculated volume into the syringe, expel any air bubbles, and verify the final volume.
Injection technique:
- Restrain the rat gently, using a restraining device or manual grip that minimizes stress.
- For IP injection, insert the needle at a 30‑45° angle into the lower right quadrant of the abdomen, avoiding the intestines. Aspirate lightly to confirm no blood return, then deliver the solution steadily.
- For SC injection, lift a fold of skin on the dorsal flank, insert the needle at a 45° angle, and deposit the fluid.
- For IV injection, locate the tail vein, warm the tail to dilate the vessel, insert the needle bevel up, and inject the solution slowly.
After administration, observe the rat for at least 10 minutes. Monitor for signs of distress, changes in respiration, or abnormal motor activity. Record the injection time, dose, route, and any immediate reactions in the experimental log.
Clean all equipment with appropriate disinfectants and dispose of sharps according to institutional safety protocols.