November 1997
Volume 38, Issue 12
Free
Articles  |   November 1997
Interendothelial junctions in normal human Schlemm's canal respond to changes in pressure.
Author Affiliations
  • W Ye
    Eye Pathology Laboratory, Boston University School of Medicine, Massachusetts 02118, USA.
  • H Gong
    Eye Pathology Laboratory, Boston University School of Medicine, Massachusetts 02118, USA.
  • A Sit
    Eye Pathology Laboratory, Boston University School of Medicine, Massachusetts 02118, USA.
  • M Johnson
    Eye Pathology Laboratory, Boston University School of Medicine, Massachusetts 02118, USA.
  • T F Freddo
    Eye Pathology Laboratory, Boston University School of Medicine, Massachusetts 02118, USA.
Investigative Ophthalmology & Visual Science November 1997, Vol.38, 2460-2468. doi:
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      W Ye, H Gong, A Sit, M Johnson, T F Freddo; Interendothelial junctions in normal human Schlemm's canal respond to changes in pressure.. Invest. Ophthalmol. Vis. Sci. 1997;38(12):2460-2468.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

PURPOSE: To determine if changes in the structure and complexity of junctions between endothelial cells lining Schlemm's canal (SC) occur in normal human eyes with changes in perfusion pressure. METHODS: Twelve normal human eyes were either perfusion-fixed (at 15 or 45 mm Hg) or immersion-fixed (0 mm Hg) in modified Karnovsky's fluid. 'Outflow facility was measured continually during the perfusion fixation. The intercellular junctions of the endothelial cells of SC were ultrastructurally examined in thin sections, including serial sections and freeze-fracture replicas. Morphometric data on the number of junctional strands per total length of tight junction were documented and categorized by the number of strands (one, two, or three or more). The length of endothelial cell overlap was measured on thin sections. RESULTS: In freeze-fracture replicas, perfusion-fixed eyes demonstrated less complex junctions. At 15 mm Hg, 18.06% of the total junctional length was represented by three or more strands; at 45 mm Hg, this percentage decreased to 8.59%. In immersion-fixed eyes, 24.17% of the total junctional length was represented by three or more strands. These differences were statistically significant (P < 0.0012). In sections, the amount of endothelial cell overlap, and thus the length of paracellular pathway, was reduced in perfusion-fixed versus immersion-fixed eyes (P < 0.02). Extensive serial sectioning demonstrated that giant vacuoles were formed, either by individual endothelial cells or by two or more adjacent endothelial cells. CONCLUSIONS: When compared with specimens fixed at zero pressure, overlap between endothelial cells of SC is reduced significantly when this cell layer is under conditions of flow similar to those encountered in vivo. The tight junctions between cells of the inner wall of SC become less complex with increasing pressure. Our data suggest that the paracellular pathway into SC in the normal eye is sensitive to modulation within a range of physiologically relevant pressures.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×