HISTOCHEMICAL STUDY 



OF THE CONNECTIVE-TISSUE CHANGES 



OBSERVED IN THE COURSE 



OF DEVELOPMENT OF INDUCED SARCOMAS 



IN RATS 



JU. M. VASILIEV 



Institute of expérimental and clinical oncology, Moscow 



The changes in the subcutaneous connective tissue of rats after implan- i 

 tation of pellets containing carcinogenic hydrocarbons were studied. 

 Sections and spreads of the connective tissue surrounding thèse pellets 

 were prepared. More than 20 varions morphological and histochemical 

 methods were used, among them reactions for nucleic acids, for proteins, 

 for lipides, for différent enzymes, supravital staining with neutral red 

 and supravital fluorescent-microscopic examination, method for démonstra- 

 tion of labile components of intercellular substance developed by author, 

 etc. 



It was shown, that carcinogenic hydrocarbons cause several types of 

 early pathological changes in the connective tissue: a) distortion of the 

 process of fibroblast's differentiation which is manifested by the changes 

 intheshape and in histochemical characteristics of thèse cells; b) accumu- 

 lation of lipides in the cytoplasm of connective tissue cells; c) distortion 

 of the process of collagen synthesis, and, especially, dissociation of 

 the formation of chromotropic muco polysaccharide (probably, hyaluronic 

 acid), of PAS-positive glycoprotein and of other collagen-fibre components. 



Thèse changes were observed only in experiments with active carci- ■ 

 nogenic hydrocarbons (9, 10-dimetnyl-l, 2-benzanthracene and 20-methyl- I 

 cholanthrene); they were not seen in control experiments with pellets con- 

 taining only the pure solvent (paraffin) or inactive and weakly active 

 hydrocarbons (anthracene or 1, 2-benzanthracene). Possible mechanisms 

 of development of the observed connective-tissue changes and their rôle 

 in the gènes is of induced sarcomas will be discussed. 



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