Single cilia in human epidermis are susceptible to challenge.

Single cilia were found in melanocytes and basal keratinocytes in normal epidermis and in epidermis subjected to various types of exposure. Quantitative electron microscopy showed that about 31% of the melanocytes and 71% of the keratinocytes from normal skin possessed a ciliary apparatus, but there was a wide individual variation. A statistically significant decrease in the number of ciliated keratinocytes followed exposure to nickel, sodium lauryl sulphate, UVA and UVB irradiation. There was no statistically significant difference between controls and skin subjected to various exposures regarding the number of ciliated melanocytes. We have earlier reported that single cilia are frequently seen on epithelial cells capable of mitotic activity in human oral and vaginal epithelia. The present study showed that single cilia react to external exposures. The cilium might be a sensitive, easily damaged organelle, or the decrease in ciliated cells might reflect a change in normal mitotic activity as a result of exposure.