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Laboratory Animal Science (Subject) / Application methods (Lesson)
- name animal identification methods Identification methods• Ear punching, ear tags (mice, rats, pigs)• Tattooing into ear, tail or feet (mice, rats, rabbits, dogs, cats)• Dyes or coloring markings (Hair colour lotion, Edding pencil; is temporary andneeds to be renewed!)• Cutting and shaving the fur (needs to be renewed!)• implantable microchip (radio frequency) devices (mice, rats, dogs, cats)• Rings (chicken)
- requirements of injection solutions Requirements of injection solutions: germ- and pyrogen free (steril) isotonic (280-300 mosmol/kg) body-warm temperature pH-neutral (~ pH 7.4) Hyper- or hypotonic solutions or solutions with unphysiological pH-valuecan result in considerable pain and tissue damage, therefore they haveto be administered strict intravenous! – Do not inject suspensions or emulsions intravenously (risk of venousembolism)– Avoid introducing air during i.v. injecting (risk of air embolism)– Use only steril and sharp hypodermic needles and steril syringes– Multiple injections: first puncture should be as distal as possible– Desinfection of injection site using 70% alcohol
- name adminstration routes intravenous (i.v.)intraperitoneal (i.p.; note: false application; substances areabsorbed into portal vein first pass metabolism)intramuscular (painful)subcutaneous (s.c.)intracardiac (under anesthesia) intradermalintracerebroventricular (under anastehesia using stereotacticdevice)
- osmotic pumps pros and cons continous and longterm delivery of test substances subcutaneous or intraperitoneal routes no restrain, no repeated injections but implantation under anesthesia
- oral administration options (pro/con) Note:– Species specific differences in morphology, content and transit time of GIT→ enteral resorption and thus onset of effect are variable– Substances are absorbed into hephepatic portal vein first passmetabolism– Lipids are absorbed into lymphatic system (thoracic or mesenteric ductcannulation) • Administration means:1. Feed/drinking water:– stress-free– peroral for solid or liquid compounds– Effect losses due to autoclaving/light– Consider water solubility of compound if using drinking waterProblems: Feed avoidance amount or dose of given compound can not be determined 2. Administration by syringe into lower oesophagus/stomach• should be done before regular feeding• restrain the animal by the scruff (mouse, rat)• stiff, bulb-tipped steel neddles for rats/mice• flexible plastic tubes for dogs and cats Note: the needle should slide easily down the esophagusif properly placed. max. Volume depends on size of the animal 3. Administration of pills4. Oral gavage needles/gastric tubes5. Rectal administration
- methods for parenteral admnistration with skin damage:– injections and infusions– implantation of osmotic minipumps without skin damage:– aerogene administration (inhalation)– percutan administration (ointments)
- Possible vehicle solutions Depends on solubility characteristics of the compound• Water soluble:– 0.9 % saline– 5% glucose• Non-water soluble:– Propylene glycol– Dimethylsulfoxide (DMSO)
- Distinguish between blood plasma and blood serum Plasma: addition of anticoagulants (Heparin/EDTA/Na-EDTA) stabilizes blood --> centrifuge-> optain 2 phases: upper phase plasma lower phase blood cells Serum: no anticoagulants--> coagulation takes place-->centrifuge --> phase separation : upper phase serum, lower phase fibrin and blood cells
- what can be physiological effects of blood collection? • Stress reaction• Hormones• Enzymes• Blood glucose levels• Erythrocyte count• Leukocyte count• Hemoglobin• Hematocrit
- How much blood can be withdrawn? Blood volume / withdrawal intervalTotal blood volume:– ca. 7-8 ml/100 g BW (~7-8%)– ~ 70 – 80 µl/g BW ■ Mouse with 25 g ~ 1,7 to 2.0 ml Volumes: Single blood sampling: max. 10% of total blood volume ■ Mouse with 25 g max. 200 µl Repeated blood sampling: max.1% of total blood volume/day Rat with 250 g = 200 µl Mouse with 25 g max. 20 µl
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