Figure 9

Cerebellar and cortical dysmyelination in Gnpat ^−/− mice in the absence of microglia activation. (A-L) Immunohistochemistry was performed to investigate myelin (MBP), axonal loss (SMI31), microgliosis (F4/80) and oxidative stress (4-HNE and 3-nitrotyrosine). Gnpat ^−/− mice displayed a decreased amount of myelin in the cerebellar folia at three months (B), compared with the control littermates (A). Cortical demyelination was observed in a subset of three-month-old Gnpat knockout mice (G-H). Axonal loss was very mild at three weeks (C-D) and five months (E-F) and also a few axonal swellings were detectable with SMI31 (red) at five months (F, arrow and inset). Microgliosis (F4/80, green) was absent (F). 3-Nitrotyrosine (3-NT) and 4-HNE positive Purkinje cells were seen in three-week-old Gnpat ^−/− mice (J, L), in comparison with the control mice (I, K). Scale bars: A-F and I-L: 100 μm; G-H: 50 μm. (M) Quantification of mRNA levels of the pro-inflammatory markers TNFα, TLR2 and C1q by qRT-PCR. Expression levels were not elevated in four- to five-month-old Gnpat knockout mice. Values represent means ± SEM of four independent samples. Expression levels were normalized to β-actin expression. 4-HNE, 4-hydroxynonenal; TLR2, toll-like receptor 2; SEM, standard error of the mean.