Cerebellar gylcosaminoglycans as a functions of age in Fisher-344 and King (Sprague-Dawley) cesarian-derived, barrier-raised rats

The concentration and distribution of the glycosaminoglycans (GAG) in the cerebellum of two strains of cesarean-derived, barrier-raised rats were compared as a function of growth and senescence. The GAG in the cerebellum were the same as those found in the cerebral cortex: hyaluronic acid, chondroitin 4(6)-sulfate, heparan sulfate and a non-uronic acid containing glycoconjugate degraded by endo-B-D-galactosidase which was labelled "keratan sulfate." The concentration of the GAG in the cerebellum was half that in the cortex, although the relative distribution of the individual GAG components was the same as in the cerebral cortex. The concentration of the GAG in the cerebellum, relative to the DNA concentration, was one-tenth that in the cerebral cortex. As in the cerebral cortex, chondroitin 4(6)-sulfate was remarkably constant throughout the lifespan studied. In both strains of rats the concentration of "keratan sulfate" showed a peak between 2 and 3 months of age, and then gradually declined. These growth related peaks of keratan sulfate appeared to be associated with the increase of myelinated fibers and/or the proliferation of the Purkinje cell dendrites. The gradual reduction of the "keratan sulfate": chondroltin 4(6)-sulfate ratio may alter the movement of water and other molecules accounting for the reduction in extracellular space observed by others.