Robust rat pulmonary radioprotection by a lipophilic Mn N-alkylpyridylporphyrin, MnTnHex-2-PyP(5+).

Journal Article (Journal Article)

With the goal to enhance the distribution of cationic Mn porphyrins within mitochondria, the lipophilic Mn(III)meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP(5+) has been synthesized and tested in several different model of diseases, where it shows remarkable efficacy at as low as 50 µg/kg single or multiple doses. Yet, in a rat lung radioprotection study, at higher 0.6-1 mg/kg doses, due to its high accumulation and micellar character, it became toxic. To avoid the toxicity, herein the pulmonary radioprotection of MnTnHex-2-PyP(5+) was assessed at 50 µg/kg. Fischer rats were irradiated to their right hemithorax (28 Gy) and treated with 0.05 mg/kg/day of MnTnHex-2-PyP(5+) for 2 weeks by subcutaneously-implanted osmotic pumps, starting at 2 h post-radiation. The body weights and breathing frequencies were followed for 10 weeks post-radiation, when the histopathology and immunohistochemistry were assessed. Impact of MnTnHex-2-PyP(5+) on macrophage recruitment (ED-1), DNA oxidative damage (8-OHdG), TGF-β1, VEGF(A) and HIF-1α were measured. MnTnHex-2-PyP(5+) significantly decreased radiation-induced lung histopathological (H&E staining) and functional damage (breathing frequencies), suppressed oxidative stress directly (8-OHdG), or indirectly, affecting TGF-β1, VEGF (A) and HIF-1α pathways. The magnitude of the therapeutic effects is similar to the effects demonstrated under same experimental conditions with 120-fold higher dose of ~5000-fold less lipophilic Mn(III)meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+).

Full Text

Duke Authors

Cited Authors

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

Published Date

  • 2014

Published In

Volume / Issue

  • 2 /

Start / End Page

  • 400 - 410

PubMed ID

  • 24624330

Pubmed Central ID

  • PMC3949096

International Standard Serial Number (ISSN)

  • 2213-2317

Digital Object Identifier (DOI)

  • 10.1016/j.redox.2013.12.017


  • eng

Conference Location

  • Netherlands