Radioresistant Sf9 insect cells display efficient antioxidant defence against high dose γ-radiation

Abstract

Purpose: To investigate the effect of gamma radiation-induced alterations in antioxidant defence of radioresistant Sf9 insect cells.

Materials and methods: Sf9 cells were irradiated at doses ranging from 0.5–200 Gy. Lipid peroxidation and protein carbonylation levels were observed at 4 h post-exposure along with reduced glutathione/oxidized glutathione (GSH/GSSG) profile as well as specific activities of redox active enzymes superoxide dismutase (SOD), catalase, ascorbate peroxidase (APOx), and glutathione reductase (GR). Human brain malignant glioma (BMG-1) cells were used for comparing radiation response of mammalian cells.

Results: Sf9 cells displayed significantly less radiation-induced reactive oxygen/nitrogen species (ROS/RNS) generation, protein carbonylation and growth inhibition as compared to mammalian cells. Sf9 cells have higher basal APOx (∼4-fold), catalase (∼1.7-fold), SOD (∼1.3-fold) activity and GSH level (∼2.2-fold) compared to mammalian cells. A radiation dose-dependent increase in SOD, Catalase and APOx activity was found in Sf9 cells at least up to 100 Gy dose, while maximum activity in mammalian cells was achieved by 10 Gy.

Conclusion: The present study suggests that Lepidopteran insect cells carry a stronger antioxidant system that protects against radiation-induced macromolecular damage, growth inhibition and cell death.

Keywords::

• Radioresistance
• oxidative stress
• antioxidant enzymes
• lepidoptera
• Spodoptera frugiperda
• Sf9 cells

Acknowledgements

Financial support by Defense Research and Development Organization (DRDO, New Delhi, India) under Project INM-301, INM-311.1.5 as well as International Atomic Energy Agency (IAEA, Vienna, Austria) under research contract No. 15557.RB is gratefully acknowledged.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.