Metachromatic staining and electron dense reaction of glycosaminoglycans by means of Cuprolinic Blue

The distribution of proteoglycans and their association with collagen fibrils were studied in human and rabbit sclera following fixation of tissue in glutaraldehyde containing Cuprolinic Blue, a specific stain for proteoglycans when used in the presence of critical concentrations of electrolytes. Proteoglycans were visualized by electron microscopy as fine filaments, approximately 54 nm in length and 5 nm in diameter, associated with the d band in the gap zone of the periodic collagen banding pattern. Filaments were present in three orientations: (1) radiating from the d band to associate with corresponding sites on adjacent collagen fibrils; (2) encircling the collagen fibril at the d band position; and (3) lying along the fibril axis, often linking consecutive d bands. No difference was apparent between the proteoglycan-collagen organization in human and rabbit sclera. A similar arrangement of proteoglycan filaments in association with the d band was also evident throughout all levels of the sclera in spite of considerable variations in fibril diameter from inner to outer stroma. Furthermore, the specific relationship of proteoglycans with the collagen fibrils in sclera closely resembled that previously described in tendon and in articular cartilage, lending support to the view that the association of proteoglycans with collagen may be consistent in a majority of connective tissues, irrespective of their diverse functional specializations.

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Distribution of proteoglycans in the human trabecular meshwork: histochemical electron microscopic findings with cuprolinic blue

Korean Journal of Ophthalmology ◽

10.3341/kjo.1999.13.1.1 ◽

1999 ◽

Vol 13 (1) ◽

pp. 1

Author(s):

M K Ko ◽

D S Kim ◽

J C Shin

Keyword(s):

Trabecular Meshwork ◽

Electron Microscopic ◽

Cuprolinic Blue ◽

Microscopic Findings

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Compartmentation and characterization of different proteoglycans in bovine arterial wall.

Journal of Histochemistry & Cytochemistry ◽

10.1177/34.10.2427568 ◽

1986 ◽

Vol 34 (10) ◽

pp. 1293-1299 ◽

Cited By ~ 29

Author(s):

W Völker ◽

A Schmidt ◽

E Buddecke

Keyword(s):

Extracellular Matrix ◽

Arterial Wall ◽

Dermatan Sulfate ◽

Topographical Distribution ◽

Arterial Tissue ◽

Cuprolinic Blue ◽

Length Width ◽

Matrix Components ◽

The Individual

Proteoglycans stained specifically with cuprolinic blue have been visualized in electron micrographs of bovine arterial tissue. Three differently sized proteoglycan-cuprolinic blue precipitates, designated as types I, II, and III, could be detected in the extracellular matrix. The precipitates could be distinguished by their length, width, area, topographical distribution, and their characteristic association with other matrix components. By taking into account the available biochemical data and the individual susceptibilities of the precipitates towards specific glycosaminoglycan-degrading enzymes, each type of proteoglycan-cuprolinic blue precipitate could be attributed to a proteoglycan population containing dermatan sulfate, chondroitin sulfate, or heparan sulfate as its main glycosaminoglycan component.

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