Revealing the Cellular Metabolic State through NADH Autofluorescence Lifetime in Parkinson's Disease

Abstract

Cellular metabolic imaging of the relative amounts of reduced NADH and the microenvironment of this metabolic electron carrier can be used to noninvasively monitor changes in cell metabolism in various diseases. Moreover, mitochondrial dysfunction, which is directly related to the cellular metabolic state, is considered to be central in developing Parkinson's disease (PD). We applied 2-photon fluorescence lifetime imaging microscopy to determine the fluorescence lifetime as well as the amounts of reduced NADH in PC12 cells (a cell line derived from pheochromocytoma of rat adrenal medulla) treated with Neuronal Growth Factor (NGF) to differentiate into neuronal cells. The neuronal cells were further treated with MPTP to induce PD syndromes and the change in fluorescence lifetime and the amounts of reduced NADH after the treatment were measured. Our preliminary results show a significant increase in the fluorescence lifetime of free as well as bound NADH in the PD induced cells. Moreover, the relative amounts of the ratio of free NADH over bound NADH does not show any significant difference among the control and PD cells. These results may lead to further understanding of the role of cellular metabolism in PD progression.