The hippocampal fimbria of cuprizone-treated animals as a structure for studying neuroprotection in multiple sclerosis

Abstract

Objective and designIt has been demonstrated that changes in the normal-appearing white matter (NAWM) in multiple sclerosis precede the appearance of classical lesions. The understanding of NAWM biology in an established disease model might help to clarify why some of them progress to active demyelinating lesions.Material or subjectsC57BL6 male mice (19–21 g) were used in this study.TreatmentDemyelination was induced by feeding mice a diet containing 0.2% cuprizone for up to 5 weeks.MethodsRoutine stainings (luxol fast blue, and hematoxylin and eosin) and immunohistochemistry were performed to assess myelin status and the inflammatory infiltrate.ResultsWe demonstrated that, in the toxic demyelination cuprizone model, the corpus callosum is severely demyelinated after a 5-week cuprizone challenge (acute demyelination) whereas the fimbria of the hippocampus appear normal in routine myelin stainings. Microgliosis but not astrogliosis is evident after acute demyelination in the fimbria. Interestingly, both regions, the fimbria and the corpus callosum, demonstrated early oligodendrocyte apoptosis as well as intense microglia accumulation and activation. However, only the corpus callosum progresses to actively demyelination lesions whereas the fimbria does not.ConclusionsThe applied model appears suitable for elucidating pathways which promote progression of affected tissue to an active lesion.

Anatomical Distribution of Cuprizone-Induced Lesions in C57BL6 Mice

“…The hippocampal white matter area Bfimbria region,^however, appeared to be resistant to the cuprizone intoxication. Comparable results were previously reported by our group (Kipp et al 2011;Norkute et al 2009). Furthermore, the partial (i.e., lateral part) vulnerability of the caudo-putamen has been reported previously by independent groups (Pott et al 2009;Xiao et al 2008).…”

“…We started our analysis of anatomical lesions with staging of anti-Iba1-stained sections, rather than evaluating the degree of myelin loss in, for example, anti-PLP-processed slices. The reason for following this strategy was results from other studies, which indicated that microgliosis is a sensitive indicator for brain pathology, especially in humans and rodents (Kipp et al 2011;van der Valk and Amor 2009). Applying this order of looking at events in the cuprizone model, we were able to demonstrate that the lateral olfactory tract is vulnerable (i.e., displays significant microgliosis), whereas pathology is less obvious in the anti-PLP-stained section (compare Fig.…”

“…Demyelination was induced by feeding 10-week-old (19-21 g), male mice with ground standard rodent chow cont a i n i n g 0 . 2 5 % c u p r i z o n e ( b i s -c y c l o h e x a n o n e oxaldihydrazone, Sigma-Aldrich Inc., Germany) for the indicated period, as published previously Kipp et al 2011). Control mice were fed ground standard chow.…”

CXCL10 Triggers Early Microglial Activation in the Cuprizone Model

“…The procedures were approved by the Review Board for the Care of Animal Subjects of the district government (Nordrhein-Westfalen, Germany) and performed according to international guidelines on the use of laboratory mice. Demyelination was induced by feeding 8-wk-old (19-21 g) mice a diet containing 0.2% cuprizone (bis-cyclohexanone oxaldihydrazone; SigmaAldrich) in ground standard rodent chow for the indicated period (31,33). Control mice were fed standard rodent chow.…”

“…Evaluation of apoptosis on H&E stains was performed using welldefined morphological criteria, such as condensed and fragmented cell nuclei (33,39). Myelination of the CC was evaluated by two independent and blinded researchers in two different regions (area 225 and 265, according to the mouse brain atlas by Sidman et al) on a scale from 0 (complete demyelination) to 10 (normal myelination).…”