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Updated: Jul 22, 2025
Sub-acute Cerebral Microhemorrhages Induced by Lipopolysaccharide Injection in Rats
Published on: October 17, 2018
Mapping acute neuroinflammation in vivo with diffusion-MRI in rats given a systemic lipopolysaccharide challenge
Eugene Kim1, Ines Carreira Figueiredo1, Camilla Simmons1
1Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.
Abstract:
It is becoming increasingly apparent that neuroinflammation plays a critical role in an array of neurological and psychiatric disorders. Recent studies have demonstrated the potential of diffusion MRI (dMRI) to characterize changes in microglial density and morphology associated with neuroinflammation, but these were conducted mostly ex vivo and/or in extreme, non-physiological animal models. Here, we build upon these studies by investigating the utility of well-established dMRI methods to detect neuroinflammation in vivo in a more clinically relevant animal model of sickness behavior. We show that diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) indicate widespread increases in diffusivity in the brains of rats given a systemic lipopolysaccharide challenge (n = 20) vs. vehicle-treated controls (n = 12). These diffusivity changes correlated with histologically measured changes in microglial morphology, confirming the sensitivity of dMRI to neuroinflammatory processes. This study marks a further step towards establishing a noninvasive indicator of neuroinflammation, which would greatly facilitate early diagnosis and treatment monitoring in various neurological and psychiatric diseases.
Insights
Diffusion MRI (dMRI) can detect neuroinflammation in vivo. This noninvasive technique shows changes in brain diffusivity linked to microglial activity, aiding disease diagnosis.
Area of Science:
- Neuroscience
- Medical Imaging
Background:
- Neuroinflammation is implicated in neurological and psychiatric disorders.
- Diffusion MRI (dMRI) shows potential for assessing neuroinflammation, but studies are often ex vivo or use non-physiological models.
Purpose of the Study:
- To investigate the utility of established dMRI methods for detecting neuroinflammation in vivo.
- To utilize a clinically relevant animal model of sickness behavior.
Main Methods:
- Diffusion Tensor Imaging (DTI) and Neurite Orientation Dispersion and Density Imaging (NODDI) were employed.
- Systemic lipopolysaccharide challenge was administered to rats to induce neuroinflammation.
- dMRI findings were correlated with histological assessments of microglial morphology.
Main Results:
- Widespread increases in brain diffusivity were observed in rats with induced neuroinflammation compared to controls.
- Diffusion changes correlated significantly with microglial morphological alterations.
- dMRI demonstrated sensitivity to in vivo neuroinflammatory processes.
Conclusions:
- Established dMRI techniques can detect neuroinflammation noninvasively in a relevant animal model.
- This study supports dMRI as a potential tool for early diagnosis and treatment monitoring of neuroinflammatory diseases.
