Preliminary feasibility study on DTI to assess the early brain injury in germinal matrix-intraventricular hemorrhage rats

Abstract

Abstract To evaluate the feasibility and efficacy of diffusion tensor imaging (DTI) for detecting early brain microstructure alterations in germinal matrix-intraventricular hemorrhage (GMH-IVH) rat model. This study used a postnatal day 5 (PND 5) rat model of GMH-IVH. T2-weighted imaging and DTI were performed during acute (6 h and 24 h) and subacute (3d and 7d) phases after GMH-IVH. Four DTI parameters including fractional anisotropy (FA), mean diffusion (MD), axial diffusion (AD) and radial diffusion (RD) were collected in 9 specific brain regions to assess the brain microstructure alterations. Early and long-term neurological function tests were evaluated. Transcriptome sequencing analysis was also performed to investigate possible underlying mechanisms. Regional abnormalities after GMH-IVH were observed in T2-weighted images that showed significant hypointense in striatum region which close to the germinal matrix. DTI parameters also observed changes in striatum region in GMH-IVH. Alterations in other regions of brain including hippocampus, thalamus, external capsule and motor cortex also noted, which were associated with the abnormalities observed in behavioral experiments. Long-term behavioral tests show that compared to sham group, rats in GMH-IVH group caused abnormal motor function. In addition, at 24 h after GMH-IVH, transcriptome analysis results showed that the highly expressed differential genes encode hemoglobin components and down-regulate neurodevelopment-related pathways. DTI imaging allows the early assessment of neurological alteration in GMH-IVH rat pups, and providing great value in evaluating long-term behavioral deficits.