Abstract: BACKGROUND: Oligodendrocyte precursor cells are seed cells for the treatment of white matter injury. The establishment of an efficient and stable in vitro culture method is an important prerequisite for clinical transformation.

OBJECTIVE: To investigate the morphological changes of oligodendrocyte precursor cells during passage.

METHODS: Four batches of human oligodendrocyte progenitor cells were subcultured from the second generation (P2) to the seventh generation (P7) in vitro. Five pictures of 200-fold field were taken under an optical microscope before each passage. According to the cell morphology, oligodendrocyte precursor cells were divided into three types: bipolar cells (oligodendrocyte precursor cells), multipolar cells (late oligodendrocyte precursor cells) and supra-polar bifurcated cells (immature oligodendrocyte cells). The proportion of oligodendrocyte progenitor cells to the total number of cells was calculated, so as to compare the difference of cell morphology among different generations. 
RESULTS AND CONCLUSION: In the process of passage from P2 to P7, oligodendrocyte progenitor cells included three types: bipolar cells, multipolar cells and supra-polar bifurcated cells. Among them, bipolar cells and multipolar cells were the main part, and a small number of supra-polar bifurcated cells could be seen in the rest. There were no significant differences in the proportion of bipolar cells, multipolar cells and supra-polar bifurcated cells among P2-P7 (P > 0.05). The cell morphology classification and counting method can be used to preliminarily evaluate that oligodendrocyte progenitor cells have no change in morphology during culture.

Key words: oligodendrocyte progenitor cells, pre-oligodendrocytes, immature oligodendrocytes, cell passage, morphology, neural stem cells, oligodendrocytes, experiment