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In vivo quantification of the structural changes of collagens in a melanoma microenvironment with second and third harmonic generation microscopy.

Wu PC, Hsieh TY, Tsai ZU, Liu TM - Sci Rep (2015)

Bottom Line: The corresponding GLCM traces showed oscillation features and the sum of squared fluctuation VarGLCM increased with the tumor sizes.In addition, the THG intensities of the extracellular matrices increased, indicating an enhanced optical inhomogeneity.We believe these indices have the potential to help the diagnosis of skin cancers in clinical practice.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei 10617, Taiwan.

ABSTRACT
Using in vivo second harmonic generation (SHG) and third harmonic generation (THG) microscopies, we tracked the course of collagen remodeling over time in the same melanoma microenvironment within an individual mouse. The corresponding structural and morphological changes were quantitatively analyzed without labeling using an orientation index (OI), the gray level co-occurrence matrix (GLCM) method, and the intensity ratio of THG to SHG (RTHG/SHG). In the early stage of melanoma development, we found that collagen fibers adjacent to a melanoma have increased OI values and SHG intensities. In the late stages, these collagen networks have more directionality and less homogeneity. The corresponding GLCM traces showed oscillation features and the sum of squared fluctuation VarGLCM increased with the tumor sizes. In addition, the THG intensities of the extracellular matrices increased, indicating an enhanced optical inhomogeneity. Multiplying OI, VarGLCM, and RTHG/SHG together, the combinational collagen remodeling (CR) index at 4 weeks post melanoma implantation showed a 400-times higher value than normal ones. These results validate that our quantitative indices of SHG and THG microscopies are sensitive enough to diagnose the collagen remodeling in vivo. We believe these indices have the potential to help the diagnosis of skin cancers in clinical practice.

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Related in: MedlinePlus

In vivo SHG (green) and THG (magenta) imaging of the collagen remodeling and the appearance of the mouse ear (a) before melanoma implantation and (b) 2 weeks, (c) 3 weeks, and (d) 4 weeks post melanoma implantation.(a) serve as the control group.
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f6: In vivo SHG (green) and THG (magenta) imaging of the collagen remodeling and the appearance of the mouse ear (a) before melanoma implantation and (b) 2 weeks, (c) 3 weeks, and (d) 4 weeks post melanoma implantation.(a) serve as the control group.

Mentions: At a few days after the implantation of the melanoma cells, we can easily recognize strong TPF and THG contrasts in vivo, which were not present before implantation (Fig. 5). The co-localized TPF and THG signals reveal the distribution of the melanin and thus the location of the melanoma cells. Following this intrinsic feature, we can track the position of the melanoma at different stages without a label. At seven days after the implantation, the size of the tumor was so large that it can be observed with plain eyesight (Fig. 6, pictures). The black nodule grew from a 0.5 cm spot during the second week and finally reached a size of 2.0 cm. In the later stages of the melanoma development, invasion and collagen remodeling in the regions of the sebaceous glands, could be clearly observed with the SHG modality (Fig. 6). All of the vessel networks disappeared, and the “cable-like” collagens appeared with a high directionality (Fig. 6d).


In vivo quantification of the structural changes of collagens in a melanoma microenvironment with second and third harmonic generation microscopy.

Wu PC, Hsieh TY, Tsai ZU, Liu TM - Sci Rep (2015)

In vivo SHG (green) and THG (magenta) imaging of the collagen remodeling and the appearance of the mouse ear (a) before melanoma implantation and (b) 2 weeks, (c) 3 weeks, and (d) 4 weeks post melanoma implantation.(a) serve as the control group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352861&req=5

f6: In vivo SHG (green) and THG (magenta) imaging of the collagen remodeling and the appearance of the mouse ear (a) before melanoma implantation and (b) 2 weeks, (c) 3 weeks, and (d) 4 weeks post melanoma implantation.(a) serve as the control group.
Mentions: At a few days after the implantation of the melanoma cells, we can easily recognize strong TPF and THG contrasts in vivo, which were not present before implantation (Fig. 5). The co-localized TPF and THG signals reveal the distribution of the melanin and thus the location of the melanoma cells. Following this intrinsic feature, we can track the position of the melanoma at different stages without a label. At seven days after the implantation, the size of the tumor was so large that it can be observed with plain eyesight (Fig. 6, pictures). The black nodule grew from a 0.5 cm spot during the second week and finally reached a size of 2.0 cm. In the later stages of the melanoma development, invasion and collagen remodeling in the regions of the sebaceous glands, could be clearly observed with the SHG modality (Fig. 6). All of the vessel networks disappeared, and the “cable-like” collagens appeared with a high directionality (Fig. 6d).

Bottom Line: The corresponding GLCM traces showed oscillation features and the sum of squared fluctuation VarGLCM increased with the tumor sizes.In addition, the THG intensities of the extracellular matrices increased, indicating an enhanced optical inhomogeneity.We believe these indices have the potential to help the diagnosis of skin cancers in clinical practice.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei 10617, Taiwan.

ABSTRACT
Using in vivo second harmonic generation (SHG) and third harmonic generation (THG) microscopies, we tracked the course of collagen remodeling over time in the same melanoma microenvironment within an individual mouse. The corresponding structural and morphological changes were quantitatively analyzed without labeling using an orientation index (OI), the gray level co-occurrence matrix (GLCM) method, and the intensity ratio of THG to SHG (RTHG/SHG). In the early stage of melanoma development, we found that collagen fibers adjacent to a melanoma have increased OI values and SHG intensities. In the late stages, these collagen networks have more directionality and less homogeneity. The corresponding GLCM traces showed oscillation features and the sum of squared fluctuation VarGLCM increased with the tumor sizes. In addition, the THG intensities of the extracellular matrices increased, indicating an enhanced optical inhomogeneity. Multiplying OI, VarGLCM, and RTHG/SHG together, the combinational collagen remodeling (CR) index at 4 weeks post melanoma implantation showed a 400-times higher value than normal ones. These results validate that our quantitative indices of SHG and THG microscopies are sensitive enough to diagnose the collagen remodeling in vivo. We believe these indices have the potential to help the diagnosis of skin cancers in clinical practice.

Show MeSH
Related in: MedlinePlus