Abstract
Repeated injections of thiophene induce vasogenic cerbellar degeneration and local calcium deposits in the cerebellar granule cell layer in rats. Using light and electron microscopy, we investigated the formation of cerebellar calcification between 1 hour and 40 days after thiophene administration. Alizarin red S staining was used on microslicer sections to demonstrate early pathological calcium deposition.
In the cerebellum of rats that developed truncal ataxia and/or seizure,
1) pathological calcium deposits appeared in the granule cell layer and the deep cerebellar nucleus from the early stage,
2) the calcium deposits were lamellated like the annual growth rings of trees in the granule cell layer but had disappeared in the deep cerebellar nucleus at 40 days after thiophene administration, and
3) ultrastructurally, needle-like crystal deposits of calcium were found in the postsynaptic endings of the cerebellar glomeruli, perikarya of granule cells, axoplasm of myelinated fibers and presynaptic endings of deep cerebellar nuclei. It is suggested that the cerebellar calcification induced by thiophene is initiated in granule cells through an excitotoxic mechanism and/or disorder of calcium metabolism.
