A dynamic balance between neuronal death and clearance after acute brain injury.

After acute brain injury, microglial phagocytosis is overwhelmed by the number of dying cells. Under these conditions, the assumptions on which assays for neuroprotective and neurotoxic effects are based are no longer valid. Thus longitudinal assays of healthy cells, such as assessment of the fluorescence emission of transgenically-expressed proteins, provide more accurate estimates of cell death than do single-time-point anatomical or biochemical assays. More accurate estimates of death rates will increase the translatability of preclinical studies of neuroprotection and neurotoxicity.