A rapid fluorometric assay for the determination of keratinocyte proliferation in vitro

In the present study we describe a simple technique for the determination of keratinocyte proliferation in vitro, based on the hydrolysis of a fluorogenic substrate by cell esterases. Normal and transformed human keratinocytes were grown in microtiter plates and were incubated with 4-methylumbelliferyl heptanoate after 3, 5, and 7 days. The fluorescence was quantified using an automatic fluorescence detection unit. The fluorescence showed a strong correlation with the cell number at various growth phases. In addition, the method reliably detected the growth inhibitory effect of recombinant interferon gamma on human keratinocytes. The fluorometric assay is a simple, fast and reliable method to assess cell number in keratinocyte cultures.