Radachlorin as a photosensitizer

Abstract

Radachlorin is a chlorine-derivative photosensitizer used currently in photodynamic therapy (PDT). We studied photodynamic effect of Radachlorin on neurons and surrounding glial cells. The crayfish abdominal stretch receptor and abdominal nerve cord of were used as models. Radachlorin absorption spectrum contained maximums at 420 and 654 nm and fluorescence maximum at 664 nm. In the crayfish stretch receptor Radachlorin localized predominantly to the glial envelope and penetrated only slightly into the neuron. Radachlorin accumulated rapidly in the nerve cord tissue within 30 min. Its elimination in the dye-free solution occurred slower: 11% loss during 2h. Radachlorin-PDT inactivated the neuron, induced necrosis of neurons and glial cells and glial apoptosis at concentrations as low as 10^-10-10^-9 M. rapidly accumulates in the nervous tissue, mainly in glial cells. High photodynamic efficacy, the adsorption spectrum with the red maximum within the “transparency window," rapid accumulation and elimination characterize Radachlorin as a promising photosensitizer for photodynamic therapy.