Nerve Growth Factor Distribution Research Articles

Impact of Cell Type and Density on Nerve Growth Factor Distribution and Bioactivity in 3-Dimensional Collagen Gel Cultures

Impact of Cell Type and Density on Nerve Growth Factor Distribution and Bioactivity in 3-Dimensional Collagen Gel Cultures

Impact of Cell Type and Density on Nerve Growth Factor Distribution and Bioactivity in 3-Dimensional Collagen Gel Cultures

Impact of Cell Type and Density on Nerve Growth Factor Distribution and Bioactivity in 3-Dimensional Collagen Gel Cultures

Impact of Cell Type and Density on Nerve Growth Factor Distribution and Bioactivity in 3-Dimensional Collagen Gel Cultures

Local delivery of protein agents is potentially important in many tissue engineering systems. In this report, we evaluate an experimental system for measuring the rate of nerve growth factor (NGF) transport and biological activity within a 3-dimensional, tissue-like environment. Fetal brain cells or PC12 cells were suspended throughout collagen gel cultures; controlled-release matrices were used to control the spatial and temporal pattern of NGF release. Experimentally measured concentration profiles were compared to profiles predicted by a mathematical model encompassing diffusion and first-order elimination. Our results suggest that NGF moves through gels by diffusion while being eliminated at a rate that depends on cell density. Since diffusion and elimination also govern protein transport in brain tissue, the collagen gel serves as a model system that replicates the main features of transport in the brain and, therefore, can be used to identify new strategies that enhance NGF distribution in the central nervous system. As an example of the utility of this biophysical model, we demonstrate that implantation of multiple controlled-release matrices can broaden NGF distribution in gel cultures; this broadening was accompanied by a significant increase in cellular biological activity. This approach may be useful in customizing NGF distribution throughout degenerating or damaged central nervous system tissue while minimizing toxicity to surrounding healthy tissue.

Age- and sex-related differences in the nerve growth factor distribution in the rat brain

Levels of the nerve growth factor (NGF) have been measured in various brain regions of young and aged male and female rats of Wistar strain by means of a highly sensitive two-site enzyme immunoassay system for β-NGF. Among the ten regions examined, the amount of NGF per wet weight of tissue was found to be highest in the hippocampus, irrespective of the sex and age. The NGF concentration in the hippocampus of female rats at 3 months of age was comparable to that of same age males. Further, there was no significant difference in the NGF levels of the hippocampus between young and aged males. However, the NGF level was significantly lower in aged females as compared to that in 3- or 4-month-old females, and hence the marked male-female difference was found in the NGF levels in aged Wistar rats.