THE USE OF INBRED STRAINS OF ANIMALS 

 IN EXPERIMENTAL GERONTOLOGY 



O. MUHLBOCK 

 The Netherlands Cancer Institute, Amsterdam, Holland 



Introduction 



In gerontology, as in other fields, animal experiments offer 

 the advantage that certain factors can be kept constant, 

 whereas other factors can be altered as required. Another 

 advantage lies in the fact that animal experiments can be 

 repeated as often as necessary until unmistakable results 

 have been obtained. The difficulty lies in the interpretation 

 of results obtained in animals and in the correlation with 

 symptoms observed in human subjects. It can be presumed 

 that animals do not differ from man in the basic principles of 

 the process of ageing, so that valid conclusions can be reached. 

 The choice of the experimental animal is dependent on the 

 problem to be investigated. For purely practical and econo- 

 mic reasons, however, small rodents such as mice and rats are 

 usually employed for gerontological investigations. 



As in other fields of scientific experimental investigation, 

 it has been apparent from the outset that the genetic constitu- 

 tion of the animal is of paramount importance in the study of 

 senile changes. As in all other biological investigations, 

 moreover, considerable individual variations in the response 

 to environmental influences must be taken into account. In 

 view of these two facts the availability of inbred strains is of 

 great importance. 



Development and Maintenance of Inbred Strains 



Inbred strains are usually obtained by brother-to-sister 

 matings until all individuals are genetically identical and 



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