MORPHOLOGICAL MODIFICATIONS OF THE CHOROID-PLEXUS IN A RODENT MODEL OF ACUTE VENTRICULITIS INDUCED BY GRAM-NEGATIVE LIQUORAL SEPSIS - POSSIBLE IMPLICATIONS IN THE PATHOPHYSIOLOGY OF HYPERSECRETORY HYDROCEPHALUS

Gram-negative bacterial infections of the central nervous system are g enerally associated with high morbidity and mortality rates. In patien ts with ventriculitis induced by gram-negative liquoral sepsis, a redu ction in cerebrospinal fluid formation has been reported, suggesting t hat gram-negative ventriculitis is able per se to alter the normal fun ctioning of the choroid plexus. The aim of the present study was to an alyse, for the first time in the rat, the effects of acute ventriculit is on the ultrastructure of the choroid plexus. A simple and inexpensi ve experimental model of acute ventriculitis was developed: we injecte d into the cisterna magna of rats 10(3) CFU of live Escherichia coli, inducing septic ventriculitis without major neurological deficits. His tological examinations of rodent choroid plexus 24 h after the injecti on revealed patches of altered epithelium, with swollen and vacuolated ependymal cells associated with leukocyte infiltration. Electron micr oscopy demonstrated a reduced number of microvilli and flattening of t he epithelial surface. These results (a) indicate that gramnegative se ptic ventriculitis is able to induce visible ultrastructural alteratio ns of the choroid plexus which (b) are consistent with a picture of ma rked reduction of the functioning epithelial choroid plexus surface, a nd (c) highlight the potential usefulness of our rodent acute ventricu litis model for developing treatment modalities.