Injections and Dosing

The Preclinical Research Unit (PRU) provides technicians who are proficient at a wide variety of injection and dosing techniques. Whenever possible all solutions should be pharmaceutical grade. All parenteral injections can be performed without anesthesia and the recommended volumes listed are specifically for mice.

It is always suggested to contact the ASC prior to attempting administration yourself if you are unskilled at a procedure. Unskilled dosing and injection can cause a wide variety of adverse effects including inefficacy of your model and/or chronic health issues in your animals.

Common Parenteral Injections

Intravenous injections (IV) in rodents are via the tail vein and are most commonly used for dosing compounds that are poorly absorbed by the digestive tract, or for use in bone marrow transplants. The recommended volume for injection is 5.0ml/kg.

Intravenous Catheters are used for continuous infusion via an electronic infusion pump during ultrasound or other imaging procedures. We typically use modified butterfly catheters with 27-30g needles for infusion.

Intraperitoneal injections (IP) are very commonly performed in rodents and allow for the safe injection of larger volumes. Absorption of solutions is typically much slower than for IV injections. While IP injections appear to be a technically simple technique to perform, the PRU trains and monitors the competency of our technicians to ensure the substances are delivered accurately. The recommended volume for injection is 10ml/kg.

Subcutaneous injections (SC) are a rapid and simple method of parenteral substance administration. The rate of absorption is slower than other parenteral routes, but can be used for a wide variety of substances including cells for tumor formation (link coming soon), aqueous or oily fluids, depots of oily materials, and solid pellets (link coming soon). Performing SC injections correctly is critical for avoiding early ulcerations following tumor cell injections. The recommended volume for injection is 5ml/kg. Smaller and larger volumes can be used.

Intramuscular injections (IM) are administered in the thigh muscles of the hind limbs. Due to small muscle mass in rodents, administering smaller volumes over multiple injection sites is recommended to minimize adverse reactions. Irritating substances should be avoided. The recommended volume for injection is 25ul per site with a maximum volume of 50ul per site.

Intradermal injections (ID) are commonly used for vaccine administration. Administering smaller volumes over multiple injection sites is recommended to minimize adverse reactions. An injection volume of 50ul or less per site is recommended.

Other Administration Routes

Oral Gavage (OG) is one of our most commonly requested techniques as it requires moderate skill and consistency. Gavage can be performed for long-term oral dosing, including qd and bid schedules. The recommended volume for dosing via oral gavage is 5ml/kg.

Intra-tumoral injections are performed for local delivery of solutions in tumor modeling. The needle entry site should be away from the tumor to avoid early ulceration of the tumor. The recommended injection volume is 100ul per tumor but is also tumor size dependent.

Neo-natal Facial Vein injections are used for early onset models of pediatric disease and for delivery of adeno-associated virus (AAV) vectors. The temporal facial vein can be injected with volumes up to 50ul from P0-P2.

Retro-orbital injections (RO) allow access to the venous sinus as an alternative to IV injections. RO injections require scientific justification and the use of anesthesia unless otherwise contraindicated.  A maximum of two injections per eye and a maximum volume of 150ul per injection is permitted.

Intra-nasal instillations are an effective, noninvasive way to deliver substances to the upper and lower respiratory tracts. This technique is typically used for the delivery of allergens, drugs, gene therapy, immunotherapy and pathogens and requires anesthesia. Volumes for dosing range from 5-125ul with larger volumes being administered in two doses.

Intratracheal Instillation requires sedation and the use of small volumes to prevent adverse reactions. Instillations can be achieved through a modified intubation procedure or via a surgical approach which allows direct injection of the trachea.

Footpad injections are a combination of an ID and SC injection that is utilized primarily in models of immunization and inflammation. The use of small gauge needles and small volumes (less than 50ul) are recommended for injection of a single hind paw. Footpad injections require scientific justification and veterinary consultation.

Feed Administration can be performed for drug administration, obesity modeling, or for immune-compromised models that require specialized diets for health maintenance. The ASC offers feed administration when it is part of a larger study that requires other monitoring and techniques.

Stereotaxic Brain Administration is covered in more detail here. We can perform direct brain injection of cells, virus and other solutions using a KOPF stereotaxic frame and a Stoelting Quintessential Stereotaxic Injector to inject a wide range of volumes at exact perfusion rates.