title: A Comparative Study on the Life-Saving Radioprotective Effects of Vitamins A, E, C and Over-the-Counter Multivitamins.
abstract: BACKGROUND
  Oral intake of vitamins which present antioxidant characteristics can protect living organisms against oxidative damage caused by exposure to ionizing radiation. It was previously reported that administration of high levels of vitamin C can lead to increased DNA damage through production of hydroxyl radicals from hydrogen peroxide by the Fenton reaction. However, our early experiments did not confirm this hypothesis. The main goal of this study was to determine if high doses of Vit C can show life-saving radioprotective effects.
  
  
  METHODS
  Phase I: Seventy two male Balb/c mice weighing 20-25g were randomly divided into six groups of 12 animals each. Group I; Vit E for five days, Groups II and III; Vit C and Vit A. Group 4; all three vitamins. Group V; an over-the-counter multivitamin. Group VI; none of the above. Phase II: 120 male BALB/c mice weighing 20-25g were randomly divided into 12 groups of 10 each. Group I; Vit A for five days. Groups II-IV; Vit C 200 mg/kg, 400 mg/kg, 800 mg/kg, respectively. Group V-VII; Vit E at daily doses of 200 iu/kg, 400 iu/kg, 800 iu/kg, respectively. Group VIII and IX; all three vitamins at low and high doses, respectively. Group X; an over-the-counter multivitamin. Group XI; controls group and Group XII; received pure olive oil. All animals (Phases I and II) were exposed to a lethal dose of gamma rays and the survival rates of the animals were monitored and recorded continuously for 16 days after exposure.
  
  
  RESULTS
  Phase I: 14 days after irradiation the survival rate for control group was 33.33%, while the survival rates for the 1st to 5th groups were 45.45%, 81.81%, 50%, 57.14%, and 9.09% , respectively. Phase II: The survival rates in the control group and the group that only received pure olive oil, were 50% and 60%, respectively. Survival rate in the animals received Vit C at daily doses of 200 mg/kg, 400 mg/kg, 800 mg/kg, were 90%, 90% and 90%, respectively. Log rank (Mantel-Cox) test showed statistically significant differences between the survival rates in control irradiated mice (no vitamins) and mice received Vit C at daily doses of 200 mg/kg (P=0.042), 400 mg/kg (P=0.042) and 800 mg/kg (P=0.042).
  
  
  CONCLUSIONS
  Altogether, findings of this study showed that even high doses of Vit C can show life-saving radioprotective effects. The significant radioprotective effect of Vit C at doses used in this study, opens new horizons in developing non-toxic, cost effective, easily available radioprotectors in life-threatening situations such as exposure to lethal doses of ionizing radiation.  The radioprotective effect of Vit A and Vit E seem to be less efficient compared to that of Vit C.
authors.affiliation: Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran ; Professor of Medical Physics, Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: S M J
authors.initials: SM
authors.lastname: Mortazavi
authors.affiliation: Master Student of Medical Physics, Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Rahimi
authors.affiliation: Head of Radiotherapy Physics Department, Assistant Professor of Medical Physics, Namazi Teaching Hospital, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: M A
authors.initials: MA
authors.lastname: Mosleh-Shirazi
authors.affiliation: Radiologic Technology Student, Radiology Department, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Arjomandi
authors.affiliation: Ph.D Student of Epidemiology, Epidemiology Department, School of Public Health, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Soleimani
authors.affiliation: Center of comparative and experimental medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: O
authors.initials: O
authors.lastname: Koohi Hossein-Abadi
authors.affiliation: Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Haghani
authors.affiliation: Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Alavi
keywords: Ascorbic Acid; Radiation; Radioprotective Effects; Survival; Vitamin C