Resazurin detection of energy metabolism changes in serum-starved PC12 cells and of neuroprotective agent effect.

Resazurin is a dye, which becomes fluorescent when reduced by oxidoreductases within viable cells. Measurement of resazurin fluorescence is therefore an indicator of the cell's energy metabolism. Resazurin was used here to detect metabolic changes in PC12 cells following serum starvation. Serum withdrawal is a cytotoxic environmental change resulting in cell death in cultured cell lines as well as in primary cells of various tissue origins, including nerve cells. In particular, PC12 cells have been widely employed as a neuronal cell model and a large number of studies generated. Many molecular and morphological changes occur in PC12 cells after serum withdrawal, and apoptotic cell death is the final consequence. We show that resazurin can detect the metabolic impairment in serum-deprived PC12 cells and can measure the neuroprotective properties of PACAP 1-38, as early as day 1 after serum withdrawal. Resazurin constitutes an advantageous tool to discriminate between healthy and metabolically impaired cells, since fluorescence produced by the reduced dye can be measured in living cells without a lysis step. The experiment is fast, inexpensive, uses a small amount of cells and can easily be automated.