Influence of Perineurial Cells and Toll-Like Receptors 2 and 9 on Herpes simplex Type 1 Entry to the Central Nervous System in Rat Encephalitis
Figure 2
HSV-1 infected perineurium and changed GFAP expression in the whiskers area of susceptible DA rats.
Schematic drawings of the peripheral nerve structure in the whiskers area and the localization of the HSV-1 staining (A and B) and immunofluorescence micrographs showing sections of the whiskers area at 3 dpi (C–H). The DA (A, C, E, G) and the PVG (B, D, F, H) sections were stained with HSV-1 marker (green, C–F), neuronal marker Tuj1 (red, C and D), oligodendroglia marker O4 (red, E and F), phago-lysosome marker ED1 (red, G and H) and Schwann cell marker GFAP (green, G and H). (A, C and E) In DA rats increased HSV-1 staining (green) was observed in the perineurial cell layer (arrowheads in C) surrounding nerve fascicles stained with the neuronal marker Tuj1 (red) and oligodendrocyte marker O4 (red) at 3 dpi. HSV-1 staining was also found in the epineurium (large arrow in C) and at increased level in the endoneurium (small arrow in C). (B, D and F) In PVG rats no HSV-1 staining was visualized in the perineurial cell layer at 3 dpi (arrowheads in D), instead HSV-1 was strictly confined to the outer part of the epineurium (large arrow in D). (G and H) Schwann cells stained with GFAP (green) displayed an altered morphology in the nerve fascicles of the DA rats at 3 dpi, a finding not present in PVG rats. Green stars represent HSV-1; arrowheads indicate the perineurial cell layer; large arrows indicate HSV-1 staining in the epineurium; small arrow indicates HSV-1 staining in the endoneurium; n, nerve fascicle. Scale bar: 50 µm.