Kinetics of optical properties of sensitized by ICG adipose tissue in vitro selectively irradiated by infrared laser

Transcription

1 Saratov Fall Meeting SFM 14 Kinetics of optical properties of sensitized by ICG adipose tissue in vitro selectively irradiated by infrared laser I.Yu. Yanina 1,2, V.A. Doubrovsky, 1 V.V. Tuchin 2,3,4 1 Saratov State Medical University (SSMU), Russia 2 Saratov State University (SSU), Russia 3 Institute of Precise Mechanics and Control RAS, Russia 4 University of Oulu, Finland Saratov, 2014

2 Outline Motivation Objectives Experimental setup Materials and methods Experimental results Discussion / Conclusion Acknowledgements

3 Motivation Recently we have shown that if the adipose tissue, stained with brilliant green (BG) or indocyanine green (ICG), is exposed to radiation of an appropriate light source (LED lamp or NIR laser), the photodynamic and/or selective photothermal effects can give rise to controllable lipolysis of fat cells and their gradual destruction following the scenario of apoptosis and/or necrosis. The following facts in support of our hypothesis that photodynamic action leads to fat cell lipolysis could be: 1.via increase of cell membrane permeability intercellular content flow out of cells and fill up the intracellular areas; 2.this leads to refractive indices matching of intercellular and intracellular spaces; 3.as a result optical transmittance T becomes more homogeneous within the tissue area under photodynamic action.

4 Motivation It is shown experimentally and statistically that a wavelength selective irradiation of tissue leads to aftereffect, namely the increase the homogeneity of fat cells optical images in time. At the same time, it is found that the mean value of tissue transmittance in its image area slightly depends upon the observation time.

5 Objectives The aim of the work is to investigate optical properties of sensitized by ICG adipose tissue in vitro selectively irradiated by infrared laser and to obtain interpretation of the results.

6 Experimental setup

7 Materials and methods The sample of adipose tissue. Slice thickness is µm Tissue Staining 1% ethanol-water solution of Indocyanine Green (1 mg/ml) Light Source Diode laser (LS-2-N , 808 nm).

8 Experimental results Optical images of the sample of adipose tissue stained by ICG after exposure to infrared laser radiation (808 nm) for different times of observation: a) immediately after exposure, t = 0 min, b) t = 10 min, c) t = 16 min, d) t = 26 min, e) t = 30 min, f) t = 37 min. Microscope objective Fat tissue temperature - 41 С.

9 Experimental results T Optical transmittance averaged over the area of the sample (1) and triple value of standard deviation 3σ T (2,3) are presented as functions of observation time t for the adipose tissue sample stained by ICG with 150 µm in width after IR laser photo action.

10 Experimental results The optical transmission of the samples averaged over their area as the functions of observation time: 1 - distilled water (the cuvette width µm); 2 - native adipose tissue; 3 irradiated adipose tissue; 4-1%- ethanol - water ICG solution without irradiation; 5-1%- ethanol - water ICG solution with IR irradiation (the cuvette width 100 µm); 6-1%- ethanol - water ICG solution with IR irradiation, excluding the impact of visible light (the cuvette width µm).

11 Discussion / Conclusion Increasing the degree of homogeneity of the image is interpreted as a result of immersion of tissue optical inhomogeneities by cell content leaking through the pores in cell membranes formed due to photochemical effect. On the other hand, besides it is shown that for the experimental conditions accepted no tissue clearing takes place. The interpretation of the effect observed: was found that the increase in the degree of optical homogeneity of tissue and, hence, its optical clearing is compensated by the decrease in the transmittance of the sensitizer, which results manifests in a weak dependence of the mean value of tissue sample optical clearing within the image area with time of observation.

12 Acknowledgments This study was supported in part by FiDiPro, TEKES Program (40111/11), Finland; Russian Presidential grant NSh