新生大鼠生发基质出血后白质损伤的动态演变:一项基于扩散张量成像的纵向研究OA

Objective:To investigate the spatiotemporal progression of white matter injury following germinal matrix hemorrhage(GMH)using multimodal magnetic resonance imaging(MRI),and to explore the neuroinflammatory response and motor function outcomes.Materials and Methods:A total of 38 postnatal day 5 Sprague-Dawley rats were randomly assigned to either a GMH group(induced by collagenase injection)or a sham-operated control group.Longitudinal MRI scans,including T2-weighted imaging(T2WI),susceptibility-weighted imaging(SWI),and diffusion tensor imaging(DTI),were performed at 12 hours,and 1,3,5,and 30 days post-surgery.Quantitative analysis of DTI parameters,fractional anisotropy(FA),mean diffusivity(MD),axial diffusivity(AD),and radial diffusivity(RD),was conducted in 7 regions of interest(ROI):the striatum,hippocampus,internal capsule,external capsule,corpus callosum,motor cortex,and somatosensory cortex.Acute neuroinflammation was assessed via Western blot(WB),quantitative real-time polymerase chain reaction(qRT-PCR),and immunohistochemistry(IHC).Long-term motor function was evaluated using the pole test.Results:DTI analysis revealed significantly decreased FA values accompanied by increased MD and RD values in multiple brain regions in the GMH group,indicating compromised white matter integrity.FA values in the striatum declined significantly from 1 day post-GMH onward(P＜0.001),and this decrease was sustained through 30 days(P=0.004),along with elevated MD and RD values(P＜0.05).In the hippocampus,FA values began to decline at 3 days post-GMH compared with controls(P＜0.05)and remained lower until 30 days(P＜0.05),with concurrent elevations in MD,AD,and RD(P＜0.05).By 30 days post-GMH,FA values in all seven ROIs on the injured side were significantly lower than those on the contralateral side(P＜0.05),indicating clear lateralization of white matter injury.Molecular analyses showed a significant upregulation of pro-inflammatory cytokines(IL-6,IL-1β,TNF-α;P＜0.001)and marked activation of both microglia and astrocytes during the acute phase post-GMH.Behavioral testing showed a significantly prolonged descent time in the pole test for the GMH group(P＜0.05),demonstrating a correlation between white matter structural damage and motor dysfunction.Conclusions:DTI sensitively captures dynamic microstructural alterations in white matter following GMH.These structural alterations are significantly associated with neuro inflammatory responses and long-term motor deficits.Our findings provide crucial imaging evidence for understanding the underlying mechanisms of GMH pathology.