Non-invasive detection of neurochemical changes prior to overt pathology in a mouse model of spinocerebellar ataxia type 1.

Spinocerebellar ataxia type 1 (SCA1) is a hereditary, progressive and fatal movement disorder that primarily affects the cerebellum. Non-invasive imaging markers to detect early disease in SCA1 will facilitate testing and implementation of potential therapies. We have previously demonstrated the sensitivity of neurochemical levels measured by (1) H magnetic resonance spectroscopy (MRS) to progressive neurodegeneration using a transgenic mouse model of SCA1. In order to investigate very early neurochemical changes related to neurodegeneration, here we utilized a knock-in mouse model, the Sca1(154Q/2Q) line, which displays milder cerebellar pathology than the transgenic model. We measured cerebellar neurochemical profiles of Sca1(154Q/2Q) mice and wild-type littermates using 9.4T MRS at ages 6, 12, 24, and 39 weeks and assessed the cerebellar pathology of a subset of the mice at each time point. The Sca1(154Q/2Q) mice displayed very mild cerebellar pathology even at 39 weeks, however, were distinguished from wild types by MRS starting at 6 weeks. Taurine and total choline levels were significantly lower at all ages and glutamine and total creatine levels were higher starting at 12 weeks in Sca1(154Q/2Q) mice than controls, demonstrating the sensitivity of neurochemical levels to neurodegeneration related changes in the absence of overt pathology. We measured cerebellar neurochemical alterations in a knock-in mouse model of spinocerebellar ataxia type 1, a hereditary movement disorder, using ultra-high field magnetic resonance spectroscopy (MRS). Very early neurochemical alterations were detectable prior to overt pathology in the volume-of-interest for MRS. Alterations were indicative of osmolytic changes and of disturbances in membrane phospholipid and energy metabolism.