FIG. 7.

Dark HRP signals are preferentially seen in areas of protruded and detached pericytes. (A–F) are representative TEM micrographs of horseradish peroxidase (HRP) distribution in non-migrated and migrated-pericyte locations in loud sound-exposed animals. (A) Electron micrographs of non-migrated pericytes are well sheathed within basement membrane and closely associated with a nearby endothelial cell. No detectable HRP signal is seen in the area after 30 min of HRP injection. (B) Dark HRP signals (black arrows) are seen in the vicinity of a detached pericyte soma (indicated by the pink square area in (B)). These are better seen under high magnification (C) from panel (B) (black arrows). (D) The cytoplasm of the endothelial cell is flattened and its luminal surface smooth in a non-migrated pericyte region. A dense basement membrane is situated between endothelial cell and pericyte (white arrow). (E) The luminal surface of the endothelial cell is undulated with microvillous protrusions (indicated by a purple box # in (E)) in a protruded pericyte region. (F) Multiple vesicles are seen at the sites of endothelial cells with loosely attached pericytes. These features are best seen in the high magnification images (#) from panel (E) and (*) from panel (F). Vesicles inside the endothelial cell and pericyte are indicated by the black arrows in the box * and box #. The luminal surface of the endothelial cell protrusion are indicated by the black arrowheads in the box #. EC: endothelial cells, PC: pericyte, BM: basement membrane, HRP: Horseradish peroxidase, RBC: red blood cell, WBC: white blood cell.