QUANTITATIVE EFFECTS OF PERIPHERAL MONOCYTES AND NERVE GROWTH-FACTOR ON CNS NEURAL MORPHOMETRIC OUTGROWTH PARAMETERS IN-VITRO

Wound healing of the central nervous system (CNS) is a complex process involving interactions between cells from both the vascular and the n eural environments, extracellular matrix proteins, and a cocktail of a gonistic and antagonistic bioactive molecules. Vascular cells, particu larly peripheral monocytes and macrophages, are believed to play an im portant role in organizing and mediating CNS tissue reactions subseque nt to penetrating injuries that compromise the blood-brain barrier. Al though many investigators have studied the effect of macrophages and m icroglia (resident brain macrophages) on neural outgrowth, little is k nown regarding monocyte effects. We have combined tissue culture, vide o microscopy, and digital image processing and analysis to quantify mo rphometric parameters of neurons exposed to monocyte secretory product s in vitro. The experimental system developed is simple in design but provides a quantitative understanding of cellular function and molecul ar mechanisms and has the ability to both study processes of graded co mplexity and relate cellular function to overall systems behavior. We evaluate the efficacy of the experimental model developed by measuring morphometric parameters of human neural cells (hNT cell line) in the presence of nerve growth factor (NGF). Results suggest that monocyte-c onditioned media (MCM) increases neuron outgrowth parameters, such as neuritic output, mean arbor output, neurite branching, and effective c ell diameter. Moreover, we show that the bioactive factor present in M CN is not IL-1 and the activity of the factor with respect to neural o utgrowth is between that of 10 and 100 ng/ml NGF. (C) 1996 Academic Pr ess, Inc.