Limits...
Central nervous system remyelination in culture--a tool for multiple sclerosis research.

Zhang H, Jarjour AA, Boyd A, Williams A - Exp. Neurol. (2011)

Bottom Line: Multiple sclerosis is a demyelinating disease of the central nervous system which only affects humans.This makes it difficult to study at a molecular level, and to develop and test potential therapies that may change the course of the disease.We report the development and characterisation of an ex vivo slice culture system using mouse brain and spinal cord, allowing investigation of myelination, demyelination and remyelination, which can be used as an initial reliable screen to select the most promising remyelination strategies.

View Article: PubMed Central - PubMed

Affiliation: MS Centre, Centre for Regenerative Medicine, University of Edinburgh, Queen's Medical Research Centre, 47 Little France Crescent, Edinburgh EH16 4TJ, Scotland, UK.

Show MeSH

Related in: MedlinePlus

Return of myelin sheaths represents true remyelination. A) Electron micrograph of myelinated axons from cerebellum at 10 DIV. Scale bar — 1 μm. B) Electron micrograph of remyelinated axons from cerebellum at 25 DIV, after LPC treatment on day 10. Note the thinner myelin per axon, especially in relation to their axon diameter. Scale bar — 1 μm. C) Electron micrograph showing a node of Ranvier present in cerebellar cultures that were allowed to remyelinate. Thus, compact myelin forms with mature paranodal structures. Scale bar — 1 μm. D) Quantification of G ratios showing larger G ratios (thinner myelin) for remyelinated axons (dark grey) than that of myelinated axons (pale grey), per axon diameter. These regression lines are significantly different using the maximum likelihood ratio test, p < 0.01 (counted from 6 cerebellar slices per group). E–F) Frequency distribution graphs of internode length in myelinated (E) and remyelinated (F) axons in the cerebellum (pale grey) and spinal cord (dark grey). There is a left shift for remyelinated axons showing that these have shorter internodes. (N = 4 experiments, a minimum of 80 internodes counted per group.) Comparisons of myelination and remyelination frequency-distribution data for both cerebellum and spinal cord is significant with p < 0.01 (Kolmogorov–Smirnov Test).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3117145&req=5

f0020: Return of myelin sheaths represents true remyelination. A) Electron micrograph of myelinated axons from cerebellum at 10 DIV. Scale bar — 1 μm. B) Electron micrograph of remyelinated axons from cerebellum at 25 DIV, after LPC treatment on day 10. Note the thinner myelin per axon, especially in relation to their axon diameter. Scale bar — 1 μm. C) Electron micrograph showing a node of Ranvier present in cerebellar cultures that were allowed to remyelinate. Thus, compact myelin forms with mature paranodal structures. Scale bar — 1 μm. D) Quantification of G ratios showing larger G ratios (thinner myelin) for remyelinated axons (dark grey) than that of myelinated axons (pale grey), per axon diameter. These regression lines are significantly different using the maximum likelihood ratio test, p < 0.01 (counted from 6 cerebellar slices per group). E–F) Frequency distribution graphs of internode length in myelinated (E) and remyelinated (F) axons in the cerebellum (pale grey) and spinal cord (dark grey). There is a left shift for remyelinated axons showing that these have shorter internodes. (N = 4 experiments, a minimum of 80 internodes counted per group.) Comparisons of myelination and remyelination frequency-distribution data for both cerebellum and spinal cord is significant with p < 0.01 (Kolmogorov–Smirnov Test).

Mentions: We considered the possibility that the apparent return of myelin sheaths in our slice system represents myelination of previously unmyelinated nerve fibres. Remyelinated myelin sheaths are thinner and have shorter internodal lengths compared to myelin sheaths formed in development (Perier and Gregoire, 1965; Prineas and Connell, 1979). To investigate whether the return of myelin sheaths after LPC treatment represents genuinely remyelinated fibres, we performed electron microscopy on cerebellar slices, to measure G-ratios (Figs. 4A–C). Myelinated fibres were measured after 10 DIV and “remyelinated” fibres at 25 DIV, with demyelination on day 10. The G ratio represents the ratio of the diameter of the axon to the diameter of the myelinated fibre and allows comparison of myelin thickness for different axon sizes. There was a marked difference between the groups, with “remyelinated” fibres having higher G ratios and thus thinner myelin sheaths. The curves of best fit through the points are shown in Fig. 4D, and these are statistically significantly different using the maximum likelihood ratio test (p < 0.05).


Central nervous system remyelination in culture--a tool for multiple sclerosis research.

Zhang H, Jarjour AA, Boyd A, Williams A - Exp. Neurol. (2011)

Return of myelin sheaths represents true remyelination. A) Electron micrograph of myelinated axons from cerebellum at 10 DIV. Scale bar — 1 μm. B) Electron micrograph of remyelinated axons from cerebellum at 25 DIV, after LPC treatment on day 10. Note the thinner myelin per axon, especially in relation to their axon diameter. Scale bar — 1 μm. C) Electron micrograph showing a node of Ranvier present in cerebellar cultures that were allowed to remyelinate. Thus, compact myelin forms with mature paranodal structures. Scale bar — 1 μm. D) Quantification of G ratios showing larger G ratios (thinner myelin) for remyelinated axons (dark grey) than that of myelinated axons (pale grey), per axon diameter. These regression lines are significantly different using the maximum likelihood ratio test, p < 0.01 (counted from 6 cerebellar slices per group). E–F) Frequency distribution graphs of internode length in myelinated (E) and remyelinated (F) axons in the cerebellum (pale grey) and spinal cord (dark grey). There is a left shift for remyelinated axons showing that these have shorter internodes. (N = 4 experiments, a minimum of 80 internodes counted per group.) Comparisons of myelination and remyelination frequency-distribution data for both cerebellum and spinal cord is significant with p < 0.01 (Kolmogorov–Smirnov Test).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117145&req=5

f0020: Return of myelin sheaths represents true remyelination. A) Electron micrograph of myelinated axons from cerebellum at 10 DIV. Scale bar — 1 μm. B) Electron micrograph of remyelinated axons from cerebellum at 25 DIV, after LPC treatment on day 10. Note the thinner myelin per axon, especially in relation to their axon diameter. Scale bar — 1 μm. C) Electron micrograph showing a node of Ranvier present in cerebellar cultures that were allowed to remyelinate. Thus, compact myelin forms with mature paranodal structures. Scale bar — 1 μm. D) Quantification of G ratios showing larger G ratios (thinner myelin) for remyelinated axons (dark grey) than that of myelinated axons (pale grey), per axon diameter. These regression lines are significantly different using the maximum likelihood ratio test, p < 0.01 (counted from 6 cerebellar slices per group). E–F) Frequency distribution graphs of internode length in myelinated (E) and remyelinated (F) axons in the cerebellum (pale grey) and spinal cord (dark grey). There is a left shift for remyelinated axons showing that these have shorter internodes. (N = 4 experiments, a minimum of 80 internodes counted per group.) Comparisons of myelination and remyelination frequency-distribution data for both cerebellum and spinal cord is significant with p < 0.01 (Kolmogorov–Smirnov Test).
Mentions: We considered the possibility that the apparent return of myelin sheaths in our slice system represents myelination of previously unmyelinated nerve fibres. Remyelinated myelin sheaths are thinner and have shorter internodal lengths compared to myelin sheaths formed in development (Perier and Gregoire, 1965; Prineas and Connell, 1979). To investigate whether the return of myelin sheaths after LPC treatment represents genuinely remyelinated fibres, we performed electron microscopy on cerebellar slices, to measure G-ratios (Figs. 4A–C). Myelinated fibres were measured after 10 DIV and “remyelinated” fibres at 25 DIV, with demyelination on day 10. The G ratio represents the ratio of the diameter of the axon to the diameter of the myelinated fibre and allows comparison of myelin thickness for different axon sizes. There was a marked difference between the groups, with “remyelinated” fibres having higher G ratios and thus thinner myelin sheaths. The curves of best fit through the points are shown in Fig. 4D, and these are statistically significantly different using the maximum likelihood ratio test (p < 0.05).

Bottom Line: Multiple sclerosis is a demyelinating disease of the central nervous system which only affects humans.This makes it difficult to study at a molecular level, and to develop and test potential therapies that may change the course of the disease.We report the development and characterisation of an ex vivo slice culture system using mouse brain and spinal cord, allowing investigation of myelination, demyelination and remyelination, which can be used as an initial reliable screen to select the most promising remyelination strategies.

View Article: PubMed Central - PubMed

Affiliation: MS Centre, Centre for Regenerative Medicine, University of Edinburgh, Queen's Medical Research Centre, 47 Little France Crescent, Edinburgh EH16 4TJ, Scotland, UK.

Show MeSH
Related in: MedlinePlus