In vivosilymarin’s antioxidant and anti-apoptotic effects on photodynamic therapy’s responsiveness

Abstract

Several studies have shown that some anti-oxidant natural compounds in combination with photodynamic therapy (PDT) can enhance the effectiveness of treatment. The aim of this study is to evaluate the effect of silymarin (SIL) in combination with 5,10,15,20-tetra-sulphonato-phenyl-porphyrin (TSPP) based photodynamic therapy, on experimental tumors. 30 Wistar rats with Walker carcinosarcoma, were divided into 6 groups: group 0 (control) — control, untreated group; group 1 (TSPP) — one dose of TSPP; group 2 (SIL) — silymarin; group 3 (PDT) — TSPP and irradiation 24 h after; group 4 (SIL[Formula: see text]PDT) — silymarin, TSPP and irradiation 24 h after; group 5 (SIL[Formula: see text]IR) and group 6 (IR) — irradiation and in addition, group 5 received SIL. Silymarin administered before photodynamic therapy decreased the lipid peroxidation ([Formula: see text] < 0.05) and modulated the antioxidant defense in tumor treated with PDT and silymarin suggesting that silymarin administration along with photodynamic therapy has an anti-oxidant effect. The caspase — 8 level and -3 activity increased in PDT and PDT [Formula: see text] SIL groups compared to the control; between the two groups there was a significant difference in term of apoptosis in favor to PDT. In conclusion, silymarin administration inhibited the reactive oxygen species generation and reduced the tumoral cells’ apoptosis, suggesting that natural compound administered before photodynamic therapy did not improve the therapy’s effect.