Comparison of two Mn porphyrin-based mimics of superoxide dismutase in pulmonary radioprotection.

Published

Journal Article

Development of radiation therapy (RT)-induced lung injury is associated with chronic production of reactive oxygen and nitrogen species (ROS/RNS). MnTE-2-PyP5+ is a catalytic Mn porphyrin mimic of SOD, already shown to protect lungs from RT-induced injury by scavenging ROS/RNS. The purpose of this study was to compare MnTE-2-PyP5+ with a newly introduced analogue MnTnHex-2-PyP5+, which is expected to be a more effective radioprotector due to its lipophilic properties. This study shows that Fischer rats which were irradiated to their right hemithorax (28 Gy) have less pulmonary injury as measured using breathing frequencies when treated with daily subcutaneous injections of MnTE-2-PyP5+ (3 and 6 mg/kg) or MnTnHex-2-PyP5+ (0.3, 0.6, or 1.0 mg/kg) for 2 weeks after RT. However, at 16 weeks post-RT, only MnTE-2-PyP5+ at a dose of 6 mg/kg is able to ameliorate oxidative damage, block activation of HIF-1alpha and TGF-beta, and impair upregulation of CA-IX and VEGF. MnTnHex-2-PyP5+ at a dose of 0.3 mg/kg is effective only in reducing RT-induced TGF-beta and CA-IX expression. Significant loss of body weight was observed in animals receiving MnTnHex-2-PyP5+ (0.3 and 0.6 mg/kg). MnTnHex-2-PyP5+ has the ability to dissolve lipid membranes, causing local irritation/necrosis at injection sites if given at doses of 1 mg/kg or higher. In conclusion, both compounds show an ability to ameliorate lung damage as measured using breathing frequencies and histopathologic evaluation. However, MnTE-2-PyP5+ at 6 mg/kg proved to be more effective in reducing expression of key molecular factors known to play an important role in radiation-induced lung injury.

Full Text

Duke Authors

Cited Authors

  • Gauter-Fleckenstein, B; Fleckenstein, K; Owzar, K; Jiang, C; Batinic-Haberle, I; Vujaskovic, Z

Published Date

  • March 15, 2008

Published In

Volume / Issue

  • 44 / 6

Start / End Page

  • 982 - 989

PubMed ID

  • 18082148

Pubmed Central ID

  • 18082148

International Standard Serial Number (ISSN)

  • 0891-5849

Digital Object Identifier (DOI)

  • 10.1016/j.freeradbiomed.2007.10.058

Language

  • eng

Conference Location

  • United States