Handling and injection of experimental animals

1. Handling and injection of experimental animals Lab 2

2. Objectives • After completing this laboratory exercise you should be able to know: • How to handle guinea pigs, rats and mice correctly and without fear or excitation. • How to mark groups of animals and individuals of each group correctly. • How to inject animals via various routs. • Knows about the source of immunogen and determine their efficiency in eliciting immune response.

3. Handling of animals • The general rule to handle experimental animal is to hold it firmly but gently with utmost care to avoid undue harm to the animal or yourself. • Mice are handled by the tip of the tail and let it walk on the bench, the mouse will not bite unless it is excited. • To handle a rat, wear thick cloth gloves hold white rats in your hand, hold firmly but gently avoiding undue excitation or disturbance of the animal. • Hold a rabbit using both hands by gripping its dorsal fur and skin gently and carry the animal between your arms and chest.

4. Marking of animals • Temporary marking (for short term experiments) and this type can be made by: • A card with information fastened to the out side of the cage that house individual animals such as rabbit, or group of animals such as mice or rats. • Mark by India ink or dyes such as crystal violet, safranin or malachite green on the fur of the animal. • Mark using hair clipping. • Permanent marking (for long term experiment) and this type can be made by: • Branding (burning the skin of animals with heated iron). • Ear punching by simple punching device (perforator) to punches the ear of the animals. (punches on the left hand mean multiple of 10,while punches on the right ear mean numbers from 1-9).

5. Marking of animals

6. Injection into animals • Materials can be injected into animals through several routes that include: • Intradermal (ID) injection the material within the skin. • Subcutaneous (SI) injection the material under the skin. • Intravenous (IV) injection the material in the vien. • Intraperitoneal (IP) injection the material in the peritoneal or abdomenal cavities. • Intramuscular (IM) injection the material in the muscles. • Materials to be injected should be in the form of sterile solution or suspension. Sterile syringes and suitable needle size should be used. • Skin of the animals must be wiped with 70% alcohol before injection to avoid any microbial contamination. • After filling syringes with inoculums it is extremely important to get rid of any air bubbles before injection to avoid air embolism.

7. Injection into animals • The table below shows needle size used to inject rabbit via various route (Note the smaller the gauge size of the needle the larger of the needle).

8. Immunisation of animals • Immunisationis the injection of a particular immunogen (antigen) into an animal or human to elicit a specific humoral and/or cellular immune response. Immunogens could be in two forms: • Soluble e.g. soluble protein (Ova albumin), Bovine serum albumin “ASA” and Bovine gamma globulin “BGG”) • Particles e.g. whole bacterial cells killed by heat or formalin or erythrocyte suspension.

9. Immunisation of animals • It is a common practice to mix soluble immunogen with adjuvant to enhance the antibody response in immunized animal. • Adjuvant is a mineral oil (water-in-oil emulsion) and the most common used adjuvant is Freund’s adjuvant which exists in two forms: • Complete Freund’s adjuvant (CFA) it is Freund’s adjuvant with Mycobacterium antigens. • Incomplete Freund’s adjuvant (IFA) it is Freund’s adjuvant without Mycobacterium antigens.

10. Immunisation of animals • Adjuvant is used if only small amount of soluble immunogen is available or if the material is weekly immunogen. • Adjuvant appears to work by: • Slowing the absorption of the immunogen in the tissues of the immunized animal. • Delaying the release of immunogen to the tissues and at the same time prolonging it’s elimination from the tissues. • Adjuvant-immunogen mixture are given IM, IP, SC, and ID but not IV, only native soluble immunigen can be given IV.