Animal application

Animal application

The three key stages of applying the DLW technique to animals in the lab and in the field are explained below:

We normally provide the premixed dose with recommendation on dose volume depending on your study.

Dosing subjects is performed by injection or by oral dosing. There are four alternative routes for injection: intravenous (IV), intra-muscular (IM), intra-peritoneal (IP) and sub-cutaneous (SC).

Intravenous dosing is a skilled procedure and requires training from a vet before you attempt it yourself. It is probably unfeasible in animals weighing less than 100g, and difficult in larger animals without some form of restraint or sedation. (see advice re making IV injections isotonic below)

Intra-muscular injections have been used in many studies, but these may reduce the activity of the animal post injection due to muscle damage at the injection site.

Intra-peritoneal injection is commonly used. IP injections should be made using a steep angle of entry off the midline of the body to avoid damage to internal organs. The gut recoils from the needle and the risk of puncturing it is small.

Subcutaneous injections can be used on pregnant animals or birds/reptiles carrying eggs. SC injections can be made either dorsally or ventrally. The needle is held at a shallow angle relative to the skin surface and gently pushed underneath. These are the least difficult injections to make, although they have an increased risk of leakage at the site of injection.

Once you have made entry with the needle you should depress the plunger slowly to deliver the dose, and leave the needle in place for 1-2 seconds before rapidly withdrawing it. It is unusual to get leakage with IM or IP injections. It is not generally necessary to shave or swab the skin surface injections.

Injected doses of isotopes may need to be made isotonic. In small animals (< 2kg) dosed intra-peritoneally or subcutaneously we have not routinely done this. In larger animals (>2kg), dosed by intravenous injection, the injection solutions can be made isotonic by the addition of sodium chloride. This affects the weight and volume of the administered dose, and these effects need to be accounted for when the dose is calculated.