THE COMPARATIVE CHARACTERISTIC OF MORPHOLOGY AND PROLIFERATIVE ACTIVITYOF COELOMIC FLUID AND COELOMIC EPITHELIUM CELLS IN STARFISH ASTERIAS AMURENSISAND STARFISH A. RUBENS.

Identification and characterization of cells responsible for the restoration of tissues in adult organisms is one of the main problems in regenerative biology. In this study, the comparative histological analysis of cellular suspensions in coelomic fluid (CF) and coelomic epithelium (CE) of two close species of Asteroidea has been done. Particular attention was paid to characteristics of small epithelial cells (SECs, diameter 4 mm) with high nuclear-cytoplasmic ratio more 0.9 and without visible signs of differentiation. Cells of this type constitute a significant proportion in CE in Asterias rubens, show proliferative activity and are probably the progenitor cells for the coelomocytes. Small cells with parameters identical to those of A. rubens SECs have been found both in CF and CE of A. amurensis. We have found subpopulation of weakly attached CE cells highly enriched with SECs-1. These cells were able to migrate from CE. Analysis of adhesion ability of CF and CE cells has revelaled the same patterns for these two closely releated starfish. Two-week primary cultures have demonstrated the speciality of A. amurensis CE cells consisting in the formation of «crystals», the potential centers of spiculogenesis that have not been revealed in A. rubens. Both small cells and larger cells with nuclear-cytoplasmic ration lower than 0.7 demonstrated proliferative activity in vivo and in vitro. Moreover, more high mitotic activity of coelomocytes has been found in A. amurensis. The hypotheses of coelomocytes origin are discussed.