Expression of Angiogenic Molecules in Cochlear Vasculature

Abstract

Objectives:

(1) Three-dimensionally (3D) visualize the cochlear vessels and blood-labyrinth barrier. (2) Analyze the expression of angiogenic molecules in cochlear vessels.

Methods:

Postnatal day 5 and 8-week old mice were used. After obtaining the cochlea, bony shell was removed. Whole mount immunostaining was done with endothelial cell marker PECAM-1 and VE-cadherin. NG2 and demins were used for pericyte marker. aSMA was used as vascular smooth muscle cell and S100 was used as fibrocyte marker. 3D reconstruction was done to visualize the blood-labyrinth barrier components. VEGFR2, VEGFR3, Sox17, angiopoietin-2, Dll4 were used for angiogenic markers. Claudin-5 was used to visualize the tight junction.

Results:

We could visualize the cochlear vasculature in overall, from precapillar arteriole, stria vascularis, and postcapillary venule. The relationship between components of blood-labyrinth barrier also could be visualized from basal turn to apical turn of the cochlea. Cochlear vessels well expressed VEGFR3, VEGFR2, Sox17 in the endothelial cell showing that cochlea is in active state, not static. Claudin-5 was robustly expressed suggesting its important role in blood-labyrinth barrier. aSMA was well expressed demonstrating its need for vessel contraction.

Conclusions:

A vessel is not merely a conduit for blood flow. It is newly made and is also regressed. It permits or limits many molecules on crossing over to the tissue. The cochlear vessel is an active vessel. We suggest that visualizing the cochlear vessel and checking the expression of angiogenic molecules could help understand the pathophysiology in hearing loss models.