Juvenile Taiep rats have shorter dendritic trees in the dorsal field of the hippocampus without spatial learning disabilities.

Abstract

Myelin mutant taiep rats show a progressive demyelination in the central nervous system due to an abnormal accumulation of microtubules in the cytoplasm and the processes on their oligodendrocytes. Demyelination is associated with electrophysiological alterations and the mutant had a progressive astrocytosis. The illness is associated with change in cytokine levels and in the expression of different nitric oxide synthase and concomitantly lipoperoxidation in several areas of the brain. However, until now there has been no detailed anatomical analysis of neurons in this mutant. The aim of this study was to analyze the dendritic morphology in the hippocampus using Golgi-Cox staining and spatial memory through Morris water maze test in young adult (3 months old) taiep rats and compare them with normal Sprague-Dawley. Our results showed that taiep rats have altered dendritic tree morphology in pyramidal neurons in the CA1 field of the hippocampus, but not in the CA3 region. These morphological changes did not produce a concomitant deficit in spatial memory acquisition or recall at this early stage of the disease. Our results suggest that impairment of dendritic morphology in the CA1 field of the hippocampus is a landmark of the pathology of this progressive multiple sclerosis model.