The problem of determination of cause of laboratory animal’s death: A critical review of definitions of “fatal” and “incidental” lesions

The determination of the cause of a laboratory animal’s death in gerontological experiments has become extraordinarily urgent in connection with the appearance of ideas on the programmed death of organisms. Unfortunately, the past approach to diagnosis of fatal and incidental changes based only on data of autopsy and histopathology (according to the human pathology model) is not correct for laboratory rodents. Nevertheless, the exact determination of death causes is principally possible in the future under conditions of adequate experimental design (including a large set of clinical, physiological, biochemical, and morphological examinations). However, it seems that even in this case causes of some experimental animal’s death will remain unclear.