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Magnetic Resonance Imaging and Spectroscopy Analysis in a Pelizaeus-Merzbacher Disease Rat Model
Maho Ishikawa1, Reika Sawaya1,2, Miki Hirayama2
1Department of Medical Physics and Engineering, Area of Medical Imaging Technology and Science, Division of Health Sciences, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
Abstract:
Pelizaeus−Merzbacher disease (PMD) is an X-linked recessive disorder of the central nervous system. We performed 7 Tesla magnetic resonance imaging of the brain in Tama rats, a rodent PMD model, and control rats, as well as evaluated the diagnostic values. In the white matter of the Tama rats, the T2 values were prolonged, which is similar to that observed in patients with PMD (60.7 ± 1.8 ms vs. 51.6 ± 1.3 ms, p < 0.0001). The apparent diffusion coefficient values in the white matter of the Tama rats were higher than those of the control rats (0.68 ± 0.03 × 10−3 mm2/s vs. 0.64 ± 0.03 × 10−3 mm2/s, p < 0.05). In proton magnetic resonance spectroscopy, the N-acetylaspartate (6.97 ± 0.12 mM vs. 5.98 ± 0.25 mM, p < 0.01) and N-acetylaspartate + N-acetylaspartylglutamate values of the Tama rats were higher (8.22 ± 0.17 mM vs. 7.14 ± 0.35 mM, p < 0.01) than those of the control rats. The glycerophosphocholine + phosphocholine values of the Tama rats were lower than those of the control rats (1.04 ± 0.09 mM vs. 1.45 ± 0.04 mM, p < 0.001). By using Luxol fast blue staining, we confirmed dysmyelination in the Tama rats. These results are similar to those of patients with PMD and other PMD animal models.
Insights
Pelizaeus−Merzbacher disease (PMD) research using Tama rats reveals key brain imaging differences. These findings in the rodent model mirror human PMD, aiding diagnostic value assessment.
Area of Science:
- Neuroscience
- Radiology
- Genetics
Background:
- Pelizaeus−Merzbacher disease (PMD) is a severe X-linked recessive disorder affecting central nervous system myelination.
- Understanding the neurobiological underpinnings of PMD is crucial for developing diagnostic and therapeutic strategies.
Purpose of the Study:
- To investigate the utility of 7 Tesla magnetic resonance imaging (MRI) in characterizing the brain of Tama rats, a genetic model for Pelizaeus−Merzbacher disease.
- To compare MRI findings in Tama rats with those in control rats and known human PMD patient data to evaluate diagnostic potential.
Main Methods:
- High-field (7 Tesla) MRI of the brain was performed on Tama rats (PMD model) and control rats.
- Quantitative MRI parameters including T2 values and apparent diffusion coefficients (ADC) in white matter were analyzed.
- Proton magnetic resonance spectroscopy (MRS) was used to assess levels of key brain metabolites.
- Luxol fast blue staining was employed to confirm myelination status.
Main Results:
- Tama rats exhibited prolonged white matter T2 values and increased ADC values compared to controls, indicative of white matter abnormalities.
- Proton MRS revealed elevated N-acetylaspartate (NAA) and NAA + N-acetylaspartylglutamate (NAAG) levels, and decreased glycerophosphocholine + phosphocholine (GPC+PC) levels in Tama rats.
- Luxol fast blue staining confirmed dysmyelination in the white matter of Tama rats.
- Observed changes in Tama rats closely resemble imaging and biochemical alterations seen in human PMD patients.
Conclusions:
- 7 Tesla MRI and MRS provide valuable insights into the pathophysiology of Pelizaeus−Merzbacher disease in a rodent model.
- The Tama rat model demonstrates significant white matter alterations consistent with PMD, supporting its use for studying the disease.
- These findings highlight the potential of advanced MRI techniques for diagnosing and monitoring PMD.
