The in vivo modulatory effects of Cornus mas extract on photodynamic therapy in experimental tumors

Abstract

Background: Photodynamic therapy (PDT) is a treatment of cancer due to its ability to induce cell death, oxidative stress and acute inflammatory reaction in targeted sites. To optimize the effect of PDT the addition of some compounds with supplementary cytotoxic effect on tumor cells was tried.

Methods: The study was performed on 35 Wistar male albino rats with Walker 256 carcinosarcoma. The animals were randomly assigned in seven groups (n = 5) and treated as follows: group 1 - control; group 2 - Cornus mas (CM) extract 15 mg/kg b.w., administered for 7 days; group 3 - CM extract administered for 7 days followed by irradiation (CM + IR); group 4 - one dose of tetra-p-sulfonato-phenyl-porphyrin (TSPP) 10 mg/kg b.w.; group 5 - TSPP + IR; group 6 - CM extract administered daily for 7 days before TSPP and IR (CM + TSPP + IR); group 7 - TSPP + IR followed by CM administered for 7 days (TSPP + IR + CM).

Results: The results showed that MDA and GSSG levels increased after PDT in parallel with the increasing of COX-2 expression and DNA damage. Apoptotic and necrotic index enhanced in TSPP + IR, effect improved by CM association before PDT. CM + TSPP + IR regimen also induced more intense inflammatory reactions, increased COX-2 expression, determined DNA damage, apoptosis and necrosis, compared to the TSPP + IR + CM group. Both combined therapeutic regimens reduced MDA levels in tumor tissue, especially CM + TSPP + IR and increased the antioxidant defense and iNOS expression.

Conclusions: Our results demonstrated that CM associated before PDT had beneficial effects in PDT and may represent a promising option in PDT strategies.

Keywords: Apoptosis; Cornus mas; Inflammation; Oxidative stress; Photodynamic therapy; Walker carcinosarcoma.