Intracellular formation of collagen microfibrils in granulation tissue.
It is important to determine the biosynthesis process of collagen fibers to elucidate the mechanism by which granulation tissue is induced after injury. The purpose of this study is to investigate whether collagen microfibrils can be formed not only outside but also inside a cell. Fibroblast-like cells in granulation tissue resulting from incision and ligation were examined. The cells possessed vesicles containing collagen microfibrils. The vesicles were present in connection with Golgi apparatus or the rough endoplasmic reticulum. Furthermore, the vesicles were exhibited to be secretory granules with the secretory granule marker Rab3A. The fibroblast-like cells were also indicated to be myofibroblasts, using conventional transmission electron microscopy and immunoelectron microscopy for the myofibroblast marker alpha smooth muscle actin. In conclusion, it was demonstrated that collagen microfibrils could be formed in the cell in the case of collagen fiber overproduction.
Ina
Keisuke
K
Division of Morphological Analysis, Department of Anatomy, Biology and Medicine, Faculty of Medicine, Oita University, 1-1, Idaigaoka, Hasama-machi, Oita-gun, Oita, Japan. kina@med.oita-u.ac.jp
Kitamura
Hirokazu
H
Tatsukawa
Shuji
S
Miyazaki
Takashi
T
Abe
Hirokazu
H
Fujikura
Yoshihisa
Y
D000199:Actins / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D022162:Cytoplasmic Vesicles / Q000378:metabolism / Q000648:ultrastructure; D018870:Endoplasmic Reticulum, Rough / Q000378:metabolism / Q000648:ultrastructure; D024022:Fibrillar Collagens / Q000378:metabolism* / Q000648:ultrastructure*; D005347:Fibroblasts / Q000378:metabolism / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure; D006097:Granulation Tissue / Q000378:metabolism / Q000648:ultrastructure*; D008297:Male; D046529:Microscopy, Electron, Transmission; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000648:ultrastructure; D011347:Procollagen / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D022142:Secretory Vesicles / Q000378:metabolism / Q000648:ultrastructure; D020826:rab3A GTP-Binding Protein / Q000378:metabolism
D000199:Actins; D024022:Fibrillar Collagens; D011347:Procollagen; D020826:rab3A GTP-Binding Protein