Using fourier transform infrared spectroscopy to evaluate biological effects induced by photodynamic therapy
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2016
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Lasers in Surgery and Medicine
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Background and Objective: Vibrational spectroscopic
methods associated with multivariate statistical techniques have been succeeded in discriminating skin lesions
from normal tissues. However, there is no study exploring
the potential of these techniques to assess the alterations
promoted by photodynamic effect in tissue. The present
study aims to demonstrate the ability of Fourier Transform
Infrared (FTIR) spectroscopy on Attenuated total reflection (ATR) sampling mode associated with principal
component-linear discriminant analysis (PC-LDA) to
evaluate the biochemical changes caused by photodynamic
therapy (PDT) in skin neoplastic tissue.
Materials and Methods: Cutaneous neoplastic lesions,
precursors of squamous cell carcinoma (SCC), were
chemically induced in Swiss mice and submitted to a
single session of 5-aminolevulinic acid (ALA)-mediated
PDT. Tissue sections with 5mm thickness were obtained
from formalin-fixed paraffin-embedded (FFPE) and processed prior to the histopathological analysis and spectroscopic measurements. Spectra were collected in
mid-infrared region using a FTIR spectrometer on ATR
sampling mode. Principal Component-Linear Discriminant Analysis (PC-LDA) was applied on preprocessed
second derivatives spectra. Biochemical changes were
assessed using PCA-loadings and accuracy of classification
was obtained from PC-LDA .
Results: Sub-bands of Amide I (1,624 and 1,650 cm1
) and
Amide II (1,517 cm1
) indicated a protein overexpression
in non-treated and post-PDT neoplastic tissue compared
with healthy skin, as well as a decrease in collagen fibers
(1,204, 1,236, 1,282, and 1,338 cm1
) and glycogen (1,028,
1,082, and 1,151 cm1
) content. Photosensitized neoplastic
tissue revealed shifted peak position and decreased
b-sheet secondary structure of proteins (1,624 cm1
)
amount in comparison to non-treated neoplastic lesions.
PC-LDA score plots discriminated non-treated neoplastic
skin spectra from post-PDT cutaneous lesions with
accuracy of 92.8%, whereas non-treated neoplastic skin
was discriminated from healthy tissue with 93.5% accuracy and post-PDT cutaneous lesions was discriminated
from healthy tissue with 89.7% accuracy.
Conclusion: PC-LDA was able to discriminate ATR-FTIR
spectra of non-treated and post-PDT neoplastic lesions, as well as from healthy skin. Thus, the method can be used for
early diagnosis of premalignant skin lesions, as well as to
evaluate the response to photodynamic treatment.
Como referenciar
LIMA, CASSIO A.; GOULART, VIVIANE P.; CORREA, LUCIANA; ZEZELL, DENISE M. Using fourier transform infrared spectroscopy to evaluate biological effects induced by photodynamic therapy. Lasers in Surgery and Medicine, v. 48, p. 538-545, 2016. DOI: 10.1002/lsm.22473. Disponível em: http://repositorio.ipen.br/handle/123456789/26486. Acesso em: 13 Mar 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.