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Radioprotective effect of 2-mercaptopropionylglycine on radiation-induced microsomal lipid peroxidation
Abstract:
Radiation-induced microsomal lipid peroxidation was measured following gamma-irradiation (66-399 Gy) in the presence or absence of 2-mercaptopropionylglycine (MPG) at low and high concentrations (0.03 and 0.1 mg/ml). At high concentrations of MPG, enhancement of lipid peroxidation was observed instead of reduction. Following gamma-irradiation at 266.4 Gy, lipid peroxidation increased with increasing concentrations of MPG. The spontaneous lipid peroxidation also increased with increasing concentrations of MPG. When MPG and EDTA were added together, radioprotection was observed even at high concentrations of MPG after different doses of radiation. An increase in radioprotection with increasing concentrations of MPG in the presence of EDTA at 266.4 Gy was also observed. The exogenous supply of Fe2+ during irradiation was found to eliminate the 'threshold dose' which has to be delivered before MPG shows an 'enhancement effect'. A possible mechanism for the enhancement of radiation-induced lipid peroxidation is proposed.
Insights
High concentrations of 2-mercaptopropionylglycine (MPG) enhanced radiation-induced lipid peroxidation, but MPG with EDTA showed radioprotection. Exogenous Fe2+ eliminated the threshold dose for MPG
Area of Science:
- Biochemistry
- Radiation Biology
- Oxidative Stress
Background:
- Lipid peroxidation is a key mechanism of cellular damage induced by ionizing radiation.
- 2-mercaptopropionylglycine (MPG) is a thiol-based compound investigated for potential radioprotective properties.
Purpose of the Study:
- To investigate the effect of 2-mercaptopropionylglycine (MPG) on radiation-induced lipid peroxidation.
- To explore the role of MPG concentration and the presence of EDTA in modulating radioprotection.
Main Methods:
- Gamma-irradiation of microsomal fractions at varying doses (66-399 Gy).
- Measurement of lipid peroxidation in the presence and absence of different concentrations of MPG (0.03 and 0.1 mg/ml).
- Assessment of radioprotection with combined MPG and EDTA treatment, and the effect of exogenous Fe2+.
Main Results:
- High concentrations of MPG (0.1 mg/ml) enhanced, rather than reduced, radiation-induced and spontaneous lipid peroxidation.
- Radioprotection was observed when MPG was combined with EDTA, even at high MPG concentrations.
- Increasing MPG concentrations correlated with increased radioprotection in the presence of EDTA.
- Exogenous Fe2+ eliminated the threshold dose for MPG's enhancement effect on lipid peroxidation.
Conclusions:
- MPG exhibits a dual role in radiation response, potentially enhancing lipid peroxidation at high concentrations.
- The combination of MPG and EDTA demonstrates significant radioprotective effects, suggesting a mechanism involving iron chelation.
- Understanding these concentration-dependent effects and interactions is crucial for developing effective radioprotective strategies.