Chapter 9 



AUTOLYSIS 



W, 



hen cells die they sooner or later lose their respiratory and 

 general metabolic functions, cease to move and reproduce, become 

 more acid in reaction and alter their permeability characteristics in 

 relation to macromolecules and ions. Hence their protoplasm swells 

 because of increased water intake and their mitochondria and later 

 their nuclei become water-logged. Granular bodies appear, cyto- 

 plasm and nucleus coagulate, and later lyse and disintegrate into 

 debris (Cameron, 1952) . Most, if not all, of these disturbances have 

 long been held to be the outcome of unrestricted enzymic action, 

 even when bacterial contamination is prevented. The term auto- 

 lysis refers to that phase of tissue and cell death in which cellular 

 enzymes play the chief role in breakdown, but there is nothing 

 unique in the set of changes, for they are encountered in all varieties 

 of necrosis. 



MORPHOLOGICAL CHANGES DURING AUTOLYSIS 



If a piece of liver, say from a mouse, is allowed to autolyse in 

 a sterile container under conditions closely approximating those 

 that hold when the animal dies, little happens until about six hours 

 have elapsed (Berenborn et al., 1955) . Some nuclei then show 

 pyknosis with disintegration of their membrane but the cytoplasm 

 is still apparently unaffected. Soon afterwards mitochondria begin 

 to swell and vacuolation of cytoplasm commences (Holle et al., 

 1955) . At twenty-four hours karyolysis is pronounced in areas 

 deeply placed in the tissue while hyperchromatic nuclei are numer* 

 ous everywhere. Most cells show reduced amounts of chromatin, 

 nuclear membranes are indistinct and scattered cells are breaking 

 up into granular clumps. By forty-eight to seventy-two hours most 

 of the cells are completely necrotic. 



Similar changes take place after natural death but they are soon 

 complicated by bacterial growth and putrefaction. 



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