Electrochemotherapy with Bleomycin Supported by NIRF Imaging with Indocyanine Green (ICG)-In Vitro and In Vivo Case Study

Electrochemotherapy (ECT) with bleomycin has been effectively used in recent years to treat various skin tumors. Microsecond electric pulses significantly improve bleomycin (BLM) delivery and its anticancer potential. Up to now, we can determine electric field distribution in the targeted tissue, however, the distribution of the injected drug is still not well known. In this study, we propose the combination of indocyanine green (ICG) with bleomycin as a practical approach for ECT, enabling drug distribution control and detection. Normal skeletal muscle (L6) and fibrosarcoma (WEHI-164) cells were used for the viability evaluation by MTT assay after 24 and 72 h. Cells were exposed to the ESOPE protocol alone and in combination with drugs. Additionally, visualization of the uptake of ICG and ICG + BLM supported by electroporation was performed by confocal microscopy. The mast cell tumor (MCTs) was diagnosed in the feline case. The mixture of ICG + BLM was injected into the tumor, and ECT was performed under near-infrared fluorescence imaging (NIRF). The obtained results indicate the safety of the used procedure in vitro and in vivo. ICG does not affect ECT protocols in vitro. No significant cell viability decrease was noted only in the case of WEHI-164 cells post-ECT. Moreover, it does not adversely affect the procedure; in the case of in vivo surgery, it helps to control the drug distribution before and after ECT and identify the sentinel lymph node.