[Dedifferentiation and regeneration of damaged cells and tissues]

Dedifferentiation is an important event in developmental biology and morphology but frequently neglected by the biologists. In the past, attention was given predominantly to its relationship with tumorigenesis. In our series of researches, we found important and inherent relations between dedifferentiation and regeneration of damaged cells and tissues in the emergence of large numbers of Schwann cells that digested their own myelin sheath components and senescent organelles by autophagic mechanism during regeneration of the peripheral nerves following injuries, when some apocytosomes (apo+cyto+sis), by means of apocytosis (apo+cyto+sis), budded from the cells containing such primitive organelles as free ribosomes and polyribosomes and retaining a very small quantity of active mitochondria and Golgi apparatus, all characterizing an immature state of the cells after dedifferentiation. Many autophagic bodies were found enwrapped by membranes L02 cells (a liver cell line) after vincristine-induced damage, with numerous apocytosomes dissociated following budding around the cells. The cells survived the treatment presented immature appearance, a phenomenon we termed as dedifferentiation, after which the metabolic burden of the cells was relieved, the senescent and damaged organelles were cleared, and the cells resumed their viability and proliferated vigorously to repair and reconstruct the damaged tissues. As most researchers have currently give their full attention to the important role of stem cells in the regeneration of damaged cells and tissues, we, after long-term observations and experiments, propose that mature cells also take part in the regeneration and reconstruction process after dedifferentiation.