How should tylosin be injected into a rat? - briefly
Prepare a sterile tylosin solution at the calculated dose (e.g., 10–20 mg/kg) and inject it intraperitoneally with a 25‑27 G needle, limiting the volume to ≤0.2 ml per 100 g of body weight. Restrain the rat gently, disinfect the injection site, and withdraw the needle smoothly to minimize tissue damage.
How should tylosin be injected into a rat? - in detail
To administer tylosin to a laboratory rat, follow a controlled protocol that ensures accurate dosing, sterility, and animal welfare.
Prepare the drug solution. Dissolve tylosin powder in sterile physiological saline or a suitable carrier, achieving a concentration that permits injection volumes not exceeding 0.2 mL per 100 g body weight. Filter the solution through a 0.22 µm membrane to remove particulates. Store the preparation on ice and use within 30 minutes.
Determine the dose. Typical therapeutic regimens range from 10 to 30 mg/kg body weight, administered once daily. Calculate the required mass of tylosin for each animal, then convert to the corresponding volume based on the prepared concentration.
Select the injection site. The preferred route is intraperitoneal (IP) because it provides rapid systemic absorption and is technically straightforward in rats. Alternative routes—subcutaneous (SC) or intravenous (IV) via the lateral tail vein—may be employed for specific experimental designs.
Perform the injection:
- Restrain the rat gently using a restraining device or by hand, minimizing stress.
- Locate the lower right abdominal quadrant, avoiding the midline and major organs.
- Clean the skin with 70 % isopropyl alcohol; allow it to dry.
- Attach a sterile 1‑mL syringe with a 27‑gauge needle.
- Insert the needle at a 30‑45° angle, bevel up, penetrating the peritoneal cavity to a depth of 2–3 mm.
- Aspirate gently to confirm lack of blood or urine; if fluid is withdrawn, reposition the needle.
- Depress the plunger steadily to deliver the calculated volume.
- Withdraw the needle smoothly, apply gentle pressure with sterile gauze to the puncture site.
Observe the animal for at least 15 minutes after injection. Monitor for signs of distress, respiratory difficulty, or abnormal behavior. Record the injection details—date, time, dose, volume, route, and any adverse observations—in the study log.
Dispose of used needles and syringes in a designated sharps container. Clean the work area with an appropriate disinfectant before proceeding to the next animal.