[Ultrastructural study on intracerebral small blood vessels and fluorescent granular perithelial (FGP) cells in...

In order to clarify the sequential changes of the morphology of vascular cells and FGP cells under cerebral ischemia, 32 male Wistar rats were employed. The FGP cells in the present paper are distributed along cerebral microvessels, and markedly potent in the uptake capacity for endo- and exogenous substances under the physiological and pathological conditions. Under the anesthesia of pentobarbital, experimental animals suffered from cerebral ischemia were produced by (1) occlusion of bilateral vertebral arteries, (2) unilateral ligation of common carotid artery accompanied with occlusion of vertebral arteries and (3) temporary clipping of bilateral common carotid arteries accompanied with occlusion of vertebral arteries. On 1 to 14 days after the treatments mentioned above, the cerebral cortices of animals were examined with the electron microscope with paying special attention to morphological changes of FGP cells. From the observation, it is confirmed that: (1) after occlusion of vertebral arteries (first group of experimental animals), the FGP cells become edematous without any severe damage of cerebral neurons through 2 weeks.: (2) In case of the unilateral ligation of common carotid artery (second group of experimental animals), the FGP cells and neurons tend to degenerate at the ligated side on 14 days, but at the opposite side, the considerable vacuolation and swelling of the FGP cells are evident, without accompanying with any degeneration of neurons and FGP cells, and: (3) In the reflow experiment (third group of experimental animals), the neurons are not affective and the FGP cells show some degenerative changes on 7 days, but most of them recovered on 14 days. From these observations, it may be concluded that the morphological changes of FGP cells run parallel with the change of microenvironment surrounding neurons, and the FGP cells, in addition to astrocytes, are reliable morphological markers of cerebral edema.