Hereditary hydrocephalus internus in a laboratory strain of golden hamsters (Mesocricetus auratus)

Abstract

Golden hamsters of one common laboratory strain had a high incidence of hydrocephalus internus. When a severity score of hydrocephalus was used, a major autosomal recessive locus could be identified. However, when a binary score (hydrocephalus, no hydrocephalus) was used, no such major locus could be detected and results of test matings were not consistent with Mendelian inheritance. Golden hamsters with severe forms of hydrocephalus had a dorsally compressed and ventrally intact hippocampus. Implications for the behavior and well-being of affected hamsters are unknown but researchers using this strain should be aware of the likely presence of hydrocephalus.

Cotton rats (Sigmodon hispidus) with a high prevalence of hydrocephalus without clinical symptoms

“…No cotton rats were diagnosed as having severe hydrocephalus, unlike the report of Gebhardt-Henrich et al 9 The size of the telencephalon in cotton rats with moderate hydrocephalus was larger than that of the same sex and age group (Fig. 2A).…”

“…The brains were cut coronally in a plane passing through the hippocampus and the arcuate hypothalamic nucleus, and hydrocephalus was diagnosed if a minimum of one lateral ventricle was visible to the naked eye. The severity of hydrocephalus was evaluated according to a previous study on hamsters, 9 and the brains were diagnosed as being normal, mild hydrocephalus (if only the temporal region of the lateral ventricle was dilated), moderate hydrocephalus (if the parietal and temporal regions of the lateral ventricle were dilated), or severe hydrocephalus (if edematous dilatation of the brain was apparent).…”

“…8 Gebhardt-Henrich et al reported that about half of their stock colonies of golden hamsters (Mesocricetus auratus) also develop mild to severe hydrocephalus without obvious symptoms. 9 Although several laboratory models of hydrocephalus are present, a complete animal model that mimics human idiopathic NPH has not yet been established, and the accumulation of the candidates and their pathophysiological knowledge is still insufficient.…”