hypericum and Fibrosarcoma

Histomorphological changes in murine fibrosarcoma after photodynamic therapy (PDT) based on the natural photosensitizer hypericin were evaluated. C3H/DiSn mice were inoculated with fibrosarcoma G5:1:13 cells. When the tumour reached a volume of 40-80 mm(3) the mice were intraperitoneally injected with hypericin, either in a single dose (5 mg/kg; 1 or 6 h before laser irradiation) or two fractionated doses (2.5 mg/kg; 6 and 1 h before irradiation with laser light; 532 nm, 70 mW/cm(2), 168 J/cm(2)). All groups of PDT-treated animals with single and fractionated hypericin dosing presented primary vascular reactions including vascular dilatation, congestion, thrombosis and oedema. Two hours after PDT there were necrotic changes with small, rather focal appearance. One day after therapy the necrotic areas were enhanced, often affecting a complete superficial layer of tumour tissue. Necrotic areas were accompanied with inflammation and haemorrhages.

Topics: Animals; Anthracenes; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Disease Models, Animal; Fibrosarcoma; Humans; Hypericum; Injections, Intraperitoneal; Male; Mice; Mice, Inbred C3H; Perylene; Photochemotherapy; Photosensitizing Agents; Phytotherapy; Plant Extracts; Radiation Dosage

The in vivo antitumour activity of the natural photosensitizer hypericin was evaluated. C3H/DiSn mice were inoculated with fibrosarcoma G5:1:13 cells. When the tumour reached a volume of 40-80mm3 the mice were intraperitoneally injected with hypericin, either in a single dose (5mg/kg; 1 or 6h before laser irradiation) or two fractionated doses (2.5 mg/kg; 6 and 1 h before irradiation with laser light; 532 nm, 70mW/cm2, 168 J/cm2). All tumours in control groups treated with hypericin alone as well as those irradiated with laser light alone had similar growth rates and none of these tumours regressed spontaneously. Complete remission of tumour in photodynamic therapy (PDT)-treated groups was similar (14-17% single dose vs. 33% fractionated dose), but the fractionated schedule of hypericin dosing was found to be more efficient than the single dose, measured by survival assay (p < 0.05). Our experimental model showed that fractionated administration of hypericin can produce a better therapeutic response than single administration.

Topics: Animals; Anthracenes; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Drug Administration Schedule; Fibrosarcoma; Hypericum; Injections, Intraperitoneal; Light; Male; Mice; Mice, Inbred Strains; Perylene; Photochemotherapy; Photosensitizing Agents; Phytotherapy