RESUMO
OBJECTIVES: Ionising radiation has deleterious effects on human cells. N-acetylcysteine (NAC) and cysteine, the active metabolite of NAC, are well-known radioprotective agents. Recently, a serine-magnesium sulfate combination was proposed as an antidote for organophosphate toxicity. This study aimed to investigate the use of a serine-magnesium sulfate mixture in the prevention of γ-radiation-induced DNA damage in human lymphocytes as compared to NAC and cysteine. METHODS: This study was carried out at the Iran University of Medical Sciences, Tehran, Iran, between April and September 2016. Citrated blood samples of 7 mL each were taken from 22 healthy subjects. Each sample was divided into 1 mL aliquots, with the first aliquot acting as the control while the second was exposed to 2 Gy of γ-radiation at a dose rate of 102.7 cGy/minute. The remaining aliquots were separately incubated with 600 µM concentrations each of serine, magnesium sulfate, serine-magnesium sulfate, NAC and cysteine before being exposed to 2 Gy of γ-radiation. Lymphocytes were isolated using a separation medium and methyl-thiazole-tetrazolium and comet assays were used to evaluate cell viability and DNA damage, respectively. RESULTS: The serine-magnesium sulfate mixture significantly increased lymphocyte viability and reduced DNA damage in comparison to serine, magnesium sulfate, NAC or cysteine alone (P <0.01 each). CONCLUSION: The findings of the present study support the use of a serine-magnesium sulfate mixture as a new, non-toxic, potent and efficient radioprotective agent.