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Comparative sensitivity of human and rat neural cultures to chemical-induced inhibition of neurite outgrowth
Citation:
HARRILL, J., T. M. FREUDENRICH, B. ROBINETTE, AND W. R. MUNDY. Comparative sensitivity of human and rat neural cultures to chemical-induced inhibition of neurite outgrowth. TOXICOLOGY AND APPLIED PHARMACOLOGY. Academic Press Incorporated, Orlando, FL, 256(3):268-280, (2011).
Impact/Purpose:
In vitro test methods can provide a rapid approach for the screening of large numbers of chemicals for their potential to produce toxicity (hazard identification). Such screening could facilitate prioritization of resources needed for in vivo toxicity testing towards those chemicals most likely to result in adverse health effects. Cell cultures derived from nervous system tissue can be used in automated, high content screening assays to examine the chemical effects on neurite outgrowth. However, it is not clear which neuronal cell culture is the most appropriate model for screening. This study compared human and rat primary neurons as models for neurite outgrowth. The sensitivities of these models to chemicals known to affect neurite length and complexity were assessed using a high content screening system for cells grown in 96-well microplates.
Description:
There is a need for rapid, efficient and cost effective alternatives to traditional in vivo developmental neurotoxicity testing. In vitro cell culture models can recapitulate many of the key cellular processes of nervous system development, including neurite outgrowth, and may be used as screening tools to identify potential developmental neurotoxicants. The present study compared primary rat cortical cultures and human embryonic stem-cell derived neural cultures in terms of: 1) reproducibility of high-content image analysis based neurite outgrowth measurements, 2) dynamic range of neurite outgrowth measurements and 3) sensitivity to chemicals which have been shown to inhibit neurite outgrowth. There was a large increase in neurite outgrowth between 2 and 24 h in both rat and human cultures. Image analysis data collected across multiple cultures demonstrated that neurite outgrowth measurements in rat cortical cultures were more reproducible and had higher dynamic range as compared to human neural cultures. Human neural cultures were more sensitive than rat cortical cultures to chemicals previously shown to inhibit neurite outgrowth. Parallel analysis of morphological (neurite count, neurite length) and cell health (neurons per field) measurements were used to detect selective effects on neurite outgrowth. All chemicals which inhibited neurite outgrowth in rat cortical cultures did so at concentrations which did not concurrently affect the number ofneurons per field, indicating selective effects on neurite outgrowth. In contrast, more than half the chemicals which inhibited neurite outgrowth in human neural cultures did so at concentrations which concurrently decreased the number of neurons per field, indicating that effects on neurite outgrowth were secondary to cytotoxicity. Overall, these data demonstrate that the culture models performed differently in terms of reproducibility, dynamic range and sensitivity to neurite outgrowth inhibitors. While human neural cultures were more sensitive to neurite outgrowth inhibitors, they also had a lower dynamic range for detecting chemical-induced neurite outgrowth inhibition and greater variability from culture-to-culture as compared to rat primary cortical cultures.
