Study of Cell Metabolic Activities Using Fluorescence Microscopy

In the present study, cultured normal rat microvessel endothelial cells are first used to explore the feasibility of studying the cell metabolic activities by detecting autofluorescence intensities. A mercury lamp is used to induce autofluorescence emissions in cells. Under an excitation wavelength of 360nm, the emissions peak at 470 nm corresponds with the autofluorescence signature of NAD(P)H, the concentration of which has been linked to the metabolic rate of the cell. A relation between the emission intensity and the NAD(P)H concentration is established. Based upon the results and observations of the endothelial cells, a protocol is developed for studying the autofluorescence of other cultured cells. It has been long known that cancer cells divide much more rapidly than normal cells depending on the degree of the tumor malignancy. The differences in metabolic rates of normal and cancerous breast cells are explored as they relate to autofluorescence emissions at different wavelengths and intensities. The comparison results can be used as a guideline to determine whether cells are cancerous. At a tissue level, laser excitation is probably needed to obtain measurable autofluorescence signals. The potential of autofluorescence measurement as a breast cancer diagnostic tool is discussed.