Diffuse reflectance spectral detection of stress-induced stomach ulcers in animal models

Transcription

1 Diffuse reflectance spectral detection of stress-induced stomach ulcers in animal models Ekaterina M. Zinchenko, Ilana M. Agranovich, Oksana V. Semyachkina-Glushkovskaya Saratov State University, Russia, Astrakhanskaya Str. 83, Saratov , Russia Ekaterina G. Borisova, Latchezar A. Avramov Institute of Electronics, Bulgarian Academy of Sciences, 72, Tsarigradsko chaussee Blvd., 1784 Sofia, Bulgaria,

2 Diffuse reflectance spectroscopy (DRS) could be a very useful tool for detection of different biological pigments, such as melanin, hemoglobin, and bilirubin. Information obtained using such optical technique could be used for an evaluation of tissue healthy state and for qualitative and quantitative analysis. We used diffuse reflectance spectroscopy technique for detection and comparison of normal and ulcerous stomach mucosa, induced under different types of stress in laboratory animals (rats). The stress types applied on the animals investigated were chemical, social, and alimentary, solely or in combination.

3 Materials and methods Set-up used for DRS investigations -Halogen lamp spectral range of emission nm Y-fiber bundle with 6 fibers for irradiation with light and 1- central fiber as optical fiber probe for diffuse-reflectance signal from the tissue USB4000 microspectrometer (USB4000, OceanOptics Inc.) nm detection range PC for storage and visualization of the spectral data

4 Broad band light illumination in the wavelength region from 400 to 900 nm was applied to obtain reflectance spectra in VIS-NIR spectral range. Fiber optical bundle was used to deliver the illumination and reflected light from the tissue site investigated. All spectra were detected on normal incidence geometry in a distance of 2 mm from the tissue surface. A microspectrometer USB4000 (OceanOptics Inc., Dunedin, USA) was applied to detect the reflectance spectra and to visualize the results. Spectra were stored in ASCII format and compared further to evaluate the differences related to the spectra detected for normal and abnormal tissue sites.

5 Experimental results DRS of ulcers

6 Experimental results hemoglobin influence In the case of ulcerous changes observed, deoxyhemoglobin is more pronounced in the spectra detected and the depth of the minimum observed at the region of nm could be used as an indicator of the pathological changes. In healthy stomach mucosa the minima in the green spectral region, related to hemoglobin absorption are well pronounced at 543 and 575 nm, which is related to the oxy-hemoglobin form in the blood.

7 Experimental results advanced stage ulcer lesions Additional decrease of the signal in the far red-near infrared spectral regions was observed for severe forms of ulcerous mucosa, which could be addressed to an increase of the products of hemoglobin dissociation in the ulcers developed.

8 Experimental results stomach ulcer imaging in different spectral ranges UV-fluorescence VIS-DRS image NIR-DRS image

9 The most significant differences observed were related to the appearance of minima in the DRS signals at the regions of nm and nm, related to the different forms of oxy and deoxyhemoglobin. Hemoglobin in its two forms is the most pronounced chromophore in evaluation of ulcer development the DRS spectral minima in the region of nm come from two minima of the oxyhemoglobin at 543 and 575 nm in healthy mucosa, to one broad minimum at nm of the the deoxyhemoglobin in ulcer lesions.

10 Further investigations are foreseen to develop correlation algorithms between the ulcer stage of development and reflectance spectra of the stomach mucosa detected. Acknowledgments: This work was supported in part by the Ministry of Education and Science of Russian Federation under Grant /K and by National Science Fund of Bulgarian Ministry of Education and Science under grant DFNI-B02/9/2014.

11 Thank you very much for your attention! Contacts: Ekaterina Borisova Institute of Electronics Bulgarian Academy of Sciences 72, Tsarigradsko chaussee Blvd Sofia, Bulgaria Tel: