A mathematical model for assessing changes in neurofilament protein levelsin neurites and cell bodies of differentiating neuroblastoma cells

A mathematical model which allows the calculation of the level of neurofila ment protein in the cell body (x) and in the neurites (y) of differentiatin g SK-N-SH cells is presented. The model considers the changes in cell numbe r (proliferating cells) and the number of cells with neurites (differentiat ing cells). It takes into account the fact that (i) when cells are cultured in differentiating conditions, an increase in cell number is initially obs erved and (ii) in a non-synchronized population of differentiating cells, t he length of neurite extended by individual cells varies within the populat ion. Total neurofilament protein levels in a population of cells were measu red by enzyme-linked immunoabsorbant assay and application of the model to the data allowed values for x and y to be calculated. The validity of the m odel is supported by the fact that the predicted total neurofilament protei n levels are highly correlated with the experimentally derived neurofilamen t protein levels. The model should be of use in temporal studies of cytoske letal proteins involved in neuronal growth/differentiation and also in stud ies in which the system is a target of toxic insult. (C) 2000 Academic Pres s.