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[Electron microscopic histochemical study in human trabecular meshwork--Second report: location of glycoconjugate
1Department of Ophthalmology, Shinshu University School of Medicine, Nagano-Ken, Japan.
Insights
Electron microscopy revealed specific glycoconjugate residues in human trabecular meshwork extracellular matrices. This finding enhances understanding of the trabecular meshwork
Area of Science:
- Ophthalmology
- Cell Biology
- Biochemistry
Context:
- The human trabecular meshwork (TM) is crucial for aqueous humor outflow and intraocular pressure regulation.
- Understanding the molecular composition of the TM extracellular matrix (ECM) is vital for glaucoma research.
- Previous studies have identified various ECM components, but lectin localization was not well-defined.
Purpose:
- To investigate the precise localization of fourteen different lectins within the normal human TM using electron microscopy.
- To identify specific glycoconjugate residues present in the TM ECM.
Summary:
- Utilized low-temperature embedding and colloidal gold labeling techniques for high-resolution electron microscopy.
- Localized lectins such as ABA, ConA, DSA, PHA-E1, PHA-L4, WGA, LCA, and RCA120 in different TM regions, including type I, II, and III plaques.
- Demonstrated the presence of specific glycoconjugate residues within the TM extracellular matrix, associated with fibrils, collagens, basal membranes, and microfibrils.
Impact:
- Provides detailed ultrastructural localization of lectins in the human TM.
- Contributes to a deeper understanding of TM ECM composition and its potential role in regulating aqueous humor dynamics.
- Offers insights relevant to the pathogenesis of glaucoma and the development of novel therapeutic strategies.
Abstract:
The location of fourteen lectins in normal human trabecular meshworks were investigated with the electron microscope. The specimens were embedded in Lowicryl K4M at low temperature. Ultrathin sections were stained with biotin labeled lectins and colloidal gold labeled streptoavidin and observed with the electron microscope. ABA, ConA, DSA, PHA-E1, PHA-L4, WGA, LCA, and RCA120 were localized around fine fibrils underneath the endothelium of the trabecular wall of the Schlemm's canal (type I plaque) and collagenous fibers in the corneoscleral meshworks. ABA, ConA, and DSA were localized on the long-spacing collagens, basal membrane, microfibrils of elastic fiber (type II plaque), and fine granular (type III plaque). The present study indicated that extracellular matrices of normal human trabecular meshworks contained specific glycoconjugate residues.