Photodynamic therapy of rat liver cancer: Protection of the normal liver by indocyanine green

Abstract

The application of photodynamic therapy (PDT) to hepatocellular carcinoma (HCC) has been difficult because hematoporphyrin derivatives (HpD) accumulate not only in cancer cells but also in normal hepatocytes and, hence, laser irradiation causes injuries in both tissues. Protection of the normal liver tissue from laser phototoxicity was demonstrated using indocyanine green (ICG) as a protective agent. In vitro, argon laser irradiation decolored the green tint of ICG much faster in solutions containing HpD than those without, suggesting that ICG captured singlet oxygen from HpD. Degeneration of Change hepatocytes induced by HpD and laser irradiation was prevented by an addition of ICG into the medium. In vivo, laser irradiation of the rat liver surface caused hyperemia when HpD was injected two days before, while the hyperemia was much milder in rats additionally receiving ICG injection 10 minutes before the irradiation. ICG injected into rat HCC accumulated only in the normal liver tissue. Laser irradiation of rat HCC preinjected with both HpD and ICG destroyed only the cancer tissue, while the surrounding liver tissue was preserved. Both in vitro and in vivo results suggest that ICG has a scavenger effect against excited oxygen and it might be used as a protective agent in PDT of HCC.

Novel photodynamic therapy against biliary tract carcinoma using mono‐l‐aspartyl chlorine e6: basic evaluation for its feasibility and efficacy

“…Almost all of them are taken up by hepatocytes and then drained by the bile. Therefore, hepatocytes are strongly affected when PDT is performed in the liver [9]. To determine the density of NPe6 in a tumor transplanted into the liver, the tumor subcutaneous transplantation model in rodents has already been established.…”

Interstitial photodynamic therapy in a rat liver metastasis model

“…The size of the tumour area on day 36 after PDT (Table III) solve the problem of efficient photosensitiser accumulation in the liver. Kita et al (1987) found that indocyanine green after i.v injection, protects photosensitised hepatocytes against illumination with green light. Nishiwaka et al (1989) used intra-arterial administration of the photosensitiser.…”

Photodynamic Therapy of Gastrointestinal Tumors: A Review

“…hence, laser irradiation causes necrosis of both diseased and healthy tissue [53]. How ever, normal healthy liver tissue was shielded from laser phototoxicity using indocyanine green as a protective agent [53]. Another way of making the PDT applicable also to liver could be the intra-arterial administration of the photosensitizer as shown by Nishiwaki et al [54] in a recent experimental study.…”

“…and. hence, laser irradiation causes necrosis of both diseased and healthy tissue [53]. How ever, normal healthy liver tissue was shielded from laser phototoxicity using indocyanine green as a protective agent [53].…”