Aqueduct stenosis induced by a single injection of antivitamin.

Hydrocephalus with aqueduct stenosis was a consistent feature in mice which received a single intraperitoneal injection of 6-aminonicotinamide (6-AN) on day 5 postnatal. Chronological investigation revealed that 6-AN-treated mice had aqueductal obstruction with edematously swollen ependymal cells and spongy changes in the periaqueductal gray matter in the early stage (on days 5 and 7 postinjection). However, these cytoplasmic edema of the ependymal and glial cells totally subsided by day 30 postinjection, leaving an obliterated aqueduct with a few remnants of ependymal cells without reactive gliosis. This abnormality of aqueductal lesions in the chronic stage was similar to those of human congenital hydrocephalus. These findings raise the possibility that some form of human congenital hydrocephalus may result from ependymal cell degeneration due to exposure to certain noxious substances in the perinatal period.