[Serial observation of human epidermal cell culture]

The primary and secondary cultures of human epidermal cells were observed serially with SEM and TEM. The cells interdigitated each other with numerous microvilli and creases on their surface. Mitoses could be seen in vigorous proliferating cells. However some cells showed degeneration and desquamation changes with less microvilli and relatively smooth surface. Once the cells became confluent, they began to stratify into basal, intermediate and upper layers or zones. The basal layer cells contained abundant organelles, free ribosomes and monofilaments with many desmosomes between the adjacent cells. The upper layer cells underwent terminal differentiation with fewer microvilli, sparse organelles even showed disorganization. As the culture time prolonged more cell showed this changes. The results here suggested that it is better to graft the confluent epidermal cell layer about three weeks after seeding as their proliferation is in good condition, and the basal cell layer should be applied onto the wound in favor of cell growth.