Ependymal denudation and secondary astroglial reaction at the aqueduct of a fetus with MMC (39 weeks GA). A. Transverse section through the aqueduct with immunostaining for caveolin. The ependymal cells are strongly reactive. Arrows indicate an area devoid of ependyma. SA = aqueduct of Sylvius. Scale bar = 100 μm. Insert: Detailed magnification of immature ependyma immunoreacting with anti-caveolin. Scale bar = 20 μm. B. Section adjacent to that of previous figure, stained with haematoxylin-eosin. Arrows indicate an area devoid of ependyma. Scale bar = 50 μm. C. Section adjacent to that of previous figure immunostained with anti-GFAP. Immunoreactive cell processes and cells (astrocytes) are confined to the denuded area (white star). Subependymal neuropil of adjacent areas lined by ependymal cells has only few astrocytes (small arrow) and virtually no astrocyte processes (black stars). The large arrow points to the border of the denuded area. Scale bar = 50 μm. Top insert: Detailed magnification of the non-reactive ependymal and subependymal neuropil. Scale bar = 30 μm. Bottom insert: numerous astrocytes (arrow) in the vicinity of the denuded area. Scale bar = 35 μm.