Choroid plexus and ageing in rats: a morphometric and ultrastructural study

Choroid plexuses (CP) are intraventricular structures involved in the produ ction of cerebrospinal fluid (CSF) and in the synthesis and transport of nu merous CSF components. Age-related modifications of the CP structure are st ill ill defined. We performed an ultrastructural and morphometric study of ageing CP in nine Sprague-Dawley rats 6, 18 and 30 months of age. Epithelia l cells of CP villi were cubic in shape at 6 months, more dome-like at 18 m onths, and significantly flattened at 30 months of age. Epithelial basement membranes were thin and regular at 6 months, significantly thicker at 18 m onths and thicker and irregular at 30 months. Intravillous stroma increased nonhomogeneously with age. The ageing of CP in rats is characterized morph ologically by epithelial atrophy, irregular fibrosis of the stroma and a th ickening of epithelial basement membranes. These modifications suggest an a lteration of secretory and filtrating functions in ageing CP.