Modeling Impaired Hippocampal Neurogenesis after Radiation Exposure

The birth of neuronal cells from neuronal stem cells is known as neurogenesis, and the granular cell layer of the dentate gyrus of hippocampus is one of the two regions in the brain this process occurs. Cognitive damages following radiation therapy for brain cancers in both children and adults have been linked to impairment of neurogenesis in the hippocampus. Studies followed using mice and rats as model animals have shown impairment in neurogenesis process following exposure to radiation. Obtaining experimental data for radiation-induced changes in neurogenesis in humans is very difficult. Model was developed and applied to mouse data previously; this study aims to apply the model to rat data. The patterns of neurogenesis impairment following radiation exposure can then provide insights for extrapolations with relevance to human physiology. A mathematical model was designed to represent the time, age and dose dependent changes occurring to several cell populations that participate in neurogenesis using nonlinear differential equations (ODE). To model the alterations in hippocampal neurogenesis following radiation exposure, four neuronal stem cell populations were considered: neural stem cells, neuroblasts, immature neurons and glioblasts. Matlab Simulink was used to solve nonlinear ODEs. With this model we were able to successfully produce data matching the experimental data for the dynamics of the rat hippocampal cell population under unirradiated and irradiated conditions. Development of these mathematical models may lead to help optimizing radiation therapy for cancer patients in the future