Study of planarian stem cell proliferation by means of flow cytometry.

The stem cells in freshwater flatworms (planarian) are called neoblasts. Neoblasts are capable of proliferation and differentiation into every cell type, including the gametes. For the investigation of the mechanisms of stem cells proliferation and differentiation the proper evaluation of changes in the cell cycle of neoblasts in different physiological conditions of planarian is necessary. In the present study the possibility of qualitative and quantitative characteristics of the neoblasts population were investigated using flow cytometry. In the cell suspension prepared from planarian tissue proliferating neoblasts have been observed in heterogenic cell population. Quantitative estimation of the cell cycle related changes of planarian stem cells system have been performed in various physiological conditions (intact and regenerating animals) and under the influence of physical (ionizing radiation) and chemical (melatonin and colchicine) factors. The modified protocol for planarian stem cells isolation proved to be effective and reproducible and can be recommended for flow cytometry analyses of human and animal proliferating cells.