Duties after experiment: euthanasia

Duties after experiment: euthanasia of animals, preservation of samples
Gábor Erős MD
Objectives:
The goal of the class is to summarize the guidelines and rules which regulate the euthanasia of
laboratory animals and to overview the techniques of extermination. Moreover, a summary is
given concerning the preservation of tissue samples obtained in an experiment.
Methodology:
This class is a seminar, no animals are used!
It is an important question how to euthanize animals in accordance with the ethical principles.
Animals shall be exterminated after experiment, if they were exposed to pain or deprivation
and their survival is not necessary for the research.
Extermination must be performed according to the following criteria:
• Suffering must be avoided
• Euthanasia shall not bias the results of the experiment
• The chosen method shall be reliable
• The chosen method shall be economically advantageous
• The chosen method shall be easy to perform
Certain methods of euthanasia can be performed by experienced persons only!
Two groups of methods can be distinguished: pharmacological (chemical) and mechanical
(physical) methods.
Pharmacological (chemical) methods:
• Overdose of narcotic gases (e.g. halothane)
• Inhalation of CO2
• Overdose of anesthetics (e.g. barbiturate)
Mechanical (physical) methods:
• Decapitation (in case of small animals)
• Cervical dislocation
• Exsanguinations
How to choose method:
• In rodents the overdose of anesthetics is the most accepted method
• Inhalation of CO2 shall be applied in animals under body weight of 500 g
• Cervical dislocation can be chosen for rodents under body weight of 100 g
• Extermination of large animals: overdose of anesthetics, exsanguinations under
anesthesia
IMPORTANT:
• Prior to application of mechanical methods it is suggested to administer sedative
and/or anesthetic drug (if possible)
• Euthanasia shall not be performed in the presence of other laboratory animals, because
it may negatively influence their physiologic parameters
Taking and preservation of tissue samples:
In the end of the experiment tissue samples shall be removed as soon as possible. Considering
the planned examination use of sterile or RN-ase free devices and techniques may be
necessary. Preservation and storage of the samples depends on the planned examination:
• If enzyme activity is to be measured, samples shall be stored under -70 °C
• If PCR is planned the fragility of mRNA shall be considered and appropriate RNA
preserving agents shall be used
• Samples are fixated in solution of formaldehyde for routine histology in most cases
• In case of immunohistochemistry it shall be considered which fixation method is
compatible with the chosen antibody
Assessment:
This class is a theoretical overview and recapitulation of duties after an experiment. The
mentioned techniques are demonstrated for the students during other lessons (experiments on
rodents and large animals). The students do not have to euthanize animals during this training.
Knowledge of the students is assessed in the final written exam.