The analysis of the shaking injury for hippocampus areas of infant rat brain by diffusion weighted imaging

Abstract

We participate in the project to establish the technique to detect an injury by shaking for brain in childhood resulted in a nerve disease at the early stage. The aim of our research as the development of method of detecting the injury with the diffusion weighted image by MRI using laboratory animals, evaluating the level of injury by using Fractional anisotropy (FA) and Trace index (TI) obtained from those images. In this presentation, we show the fluctuation of FA and TI values in the image of hippocampus of the brain of infant rat. Diffusion weighted images of hippocampus areas of postnatal 4th to 13th day rat were acquired. The FA value at molecular cell layer (Mol) is higher than that at pyramidal cell layer (Py) and dentate gyrus (DG), and the TI value at DG is lower than others. These results were similar to previous data of adult mouse though a significant conclusion was not obtained. However variations of FA value at Mol and Py that made a peak on the 10th day, and both were significantly different from at DG (two-way ANOVA: DG-Mol P=0.036, DG-Py P=0.028). But TI value at all areas had not show a peak in each day age. These results possibly are related to the expansion of the nerve fiber and the restructuring of the synapse that occur in the infant age rat brain. [J Physiol Sci. 2008;58 Suppl:S151]