Open AccessMORPHOLOGICAL CHANGES OF MYOFIBRIL IN THE CARCINOGENETIC COURSE OF 20‐METHYLCHOLANTHRENE‐INDUCED RHABDOMYOSARCOMA
Author(s) -
Hatakeyama Setsuko
Publication year - 1981
Publication title -
acta patholigica japonica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
ISSN - 0001-6632
DOI - 10.1111/j.1440-1827.1981.tb02015.x
Subject(s) - myofibril , rhabdomyosarcoma , mitosis , skeletal muscle , myocyte , pathology , biology , lesion , anatomy , regeneration (biology) , chemistry , microbiology and biotechnology , sarcoma , endocrinology , medicine
In this study 20‐methylcholanthrene (MC) was embedded in skeletal muscle tissue of mice. The resulting morphological changes were observed by light and electron microscope until the occurrence of rhabdomyosarcoma. The injected region of the muscle tissue in which MC was embedded went through three stages: destruction and degeneration, repair, and appearance of atypical cells. The morphologic figures of the myofibrils seen in the skeletal muscle cell during destruction and degeneration were similar to those observable in diseased human muscle, and were interpreted as nonspecific. The muscle tissue then regenerated in the same manner as seen during experimentally induced muscle tissue regeneration in both humans and animals. Abnormal mitotic figures were found 60 to 70 days after the injection of MC. Immature muscle cells, with tuft‐formed myofibrils present, underwent abnormal mitosis in which one of the nuclei divided. The rhabdomyosarcoma cells produced by this abnormal mitosis began to appear in the lesion 70 days after the initial embedding of MC. The rhabdomyosarcoma cells in the induced tumor formed undifferentiated myofibrils in various degrees of maturation, and were therefore considered to play a part in the abnormal myofibrillar formation.