Reduced Antigenicity of Type I Collagen and Proteoglycans in Sclerotic Dentin
P. Suppa1,
A. Ruggeri, Jr.1,
F.R. Tay2,
C. Prati3,
M. Biasotto4,
M. Falconi1,
D.H. Pashley2, and
L. Breschi4,*
1 Department of SAU & FAL, University of Bologna, Italy;
2 Department of Dental Science, University of Bologna, Italy;
3 Department of Oral Biology, School of Dentistry Medical College of Georgia, Augusta, GA, USA; and
4 Department of MUN, UCO of Dental Sciences, University of Trieste, Via Stuparich, 1, I-34129 Trieste, Italy
View larger version (92K):
[in a new window]
|
Figure 1. Field emission in-lens scanning electron micrographs (FEISEM) of sclerotic dentin after double-immunolabeling with monoclonal antibodies for type I collagen and proteoglycans. The images were obtained by a combination of secondary electron and back-scattered electron signals. (A) Low-magnification view of the surface of sclerotic dentin reveals partially patent tubular orifices surrounded by thick collars of peritubular fibrillar structures. Intertubular dentin is highly porous and is heterogeneously covered with the large (30 nm) gold particles used for labeling of antigenically intact collagen fibrils. Gold nanoparticles (15 nm) for labeling chondroitin sulfate cannot be discerned at this magnification. (B) A higher-magnification view of the sclerotic intertubular dentin, showing the labeling patterns for type I collagen (arrows) and chondroitin sulfate (open arrows). Only a few nanoparticles specific for chondroitin sulfate can be visualized at this level of magnification.
|
|
View larger version (82K):
[in a new window]
|
Figure 2. High-magnification views taken from the peritubular regions of sclerotic dentin after immunolabeling. (A) Labeling for collagen fibrils (black arrows) is sparse in this region. A few clusters of 15-nm nanoparticles (open arrowheads) that were bound to the anti-chondroitin sulfate monoclonal antibodies can also be identified. (B) Another specimen showing sparse labeling for antigenically intact type I collagen. Labeling for proteoglycans cannot be observed.
|
|
View larger version (85K):
[in a new window]
|
Figure 3. Very-high-magnification views of representative sclerotic intertubular dentin specimens after immunolabeling. (A) A specimen exhibiting moderately intense labeling for type I collagen and proteoglycans. Labeling of type I collagen is represented by the identification of larger (30 nm), discrete gold nanoparticles along the surfaces of the collagen fibrils (arrows). Labeling of proteoglycans is represented by smaller (15 nm) gold nanoparticles that appear either as discrete particles or in clusters of 2-3 particles (pointers). Collagen banding is infrequently seen on the collagen fibrils in sclerotic dentin and, when present, appears as very vague surface elevations (open arrowheads). The collagen fibrils appear collapsed and swollen, and exhibit extensive branching (asterisk) when compared with those observed in normal hard dentin (see Fig. 4 ). (B) A collapsed and swollen collagen network from another specimen of sclerotic dentin that exhibits less intense immunolabeling of both type I collagen and proteoglycans. A banded collagen fibril can be seen in the foreground (open arrowheads).
|
|
View larger version (89K):
[in a new window]
|
Figure 4. FEISEM micrographs of the collagen fibrillar network in normal hard dentin after immunolabeling. (A) Low magnification. (B) High magnification. Collagen fibrils appear unmodified, with surface cross-banding features (arrow) and gold nanoparticles (pointers) along the fibrils. Gold nanoparticles specific for proteoglycans appear as clusters of smaller electron-lucent particles around the collagen fibrils (open arrowheads). These clusters can be seen only at high magnification.
|
|
Copyright © 2006 Institutional Access Guidelines
