title: Evaluation of Chlorella as a Decorporation Agent to Enhance the Elimination of Radioactive Strontium from Body.
abstract: BACKGROUND
  Release of radionuclides, such as 137Cs and 90Sr, into the atmosphere and the ocean presents an important problem because internal exposure to 137Cs and 90Sr could be very harmful to humans. Chlorella has been reported to be effective in enhancing the excretion of heavy metals; thus, we hypothesized that Chlorella could also enhance the elimination of 137Cs or 90Sr from the body. We evaluated the potential of Chlorella as a decorporation agent in vitro and in vivo, using 85Sr instead of 90Sr.
  
  
  METHODS
  In vitro experiments of adsorption of 137Cs and 85Sr to Chlorella were performed under wide pH conditions. The maximum sorption capacity of Chlorella to strontium was estimated using the Langmuir model. A 85Sr solution was orally administrated to mice pretreated with Chlorella. At 48 h after 85Sr administration, the biodistribution of radioactivity was determined.
  
  
  RESULTS
  In the in vitro experiments, although 85Sr barely adsorbed to Chlorella at low pH, the 85Sr adsorption ratio to Chlorella increased with increasing pH. The maximum sorption capacity of Chlorella to strontium was 9.06 mg / g. 137Cs barely adsorbed to Chlorella under any pH conditions. In the biodistribution experiments, bone accumulation of radioactivity after 85Sr administration was significantly decreased in the Chlorella pretreatment group compared with the non-treatment control group.
  
  
  CONCLUSIONS
  In conclusion, these results indicated that Chlorella could inhibit the absorption of 90Sr into the blood and enhance the elimination of 90Sr from the body through adsorption in intestine. Further studies are required to elucidate the mechanism and the components of Chlorella needed for adsorption to strontium and could promote the development of more effective decorporation agents.
authors.affiliation: Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan.|Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Ogawa
authors.affiliation: Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Tadahisa
authors.initials: T
authors.lastname: Fukuda
authors.affiliation: DAESANG Corporation, Seoul, Korea.
authors.forename: Jaegab
authors.initials: J
authors.lastname: Han
authors.affiliation: Advanced Science Research Center, Kanazawa University, Kanazawa, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kitamura
authors.affiliation: Advanced Science Research Center, Kanazawa University, Kanazawa, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shiba
authors.affiliation: Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Odani
mesh_terms: D000284:Administration, Oral; D000327:Adsorption; D000818:Animals; D002412:Cations; D002708:Chlorella / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D051379:Mice; D008962:Models, Theoretical; D011848:Radioactive Pollutants / Q000302:isolation & purification*; D013326:Strontium Radioisotopes / Q000302:isolation & purification*; D014018:Tissue Distribution
chemical_list: D002412:Cations; D011848:Radioactive Pollutants; D013326:Strontium Radioisotopes
references.citation: Int J Radiat Biol Relat Stud Phys Chem Med. 1970;18(6):531-7
references.pmid: 4925187
references.citation: J Toxicol Clin Toxicol. 1992;30(2):215-22
references.pmid: 1588671
references.citation: Biol Pharm Bull. 2013;36(3):485-91
references.pmid: 23318531
references.citation: Curr Med Chem. 2012;19(20):3290-300
references.pmid: 22664247
references.citation: J Environ Radioact. 2012 Sep;111:33-7
references.pmid: 22071363
references.citation: Nature. 2011 Jun 9;474(7350):135-6
references.pmid: 21654773
references.citation: Chem Pharm Bull (Tokyo). 2012;60(10):1258-63
references.pmid: 23036968
references.citation: Bone. 2001 Apr;28(4):446-53
references.pmid: 11336927
references.citation: Nutr Res Pract. 2009 Spring;3(1):15-22
references.pmid: 20016697
references.citation: Fundam Appl Toxicol. 1993 Nov;21(4):425-32
references.pmid: 8253296
references.citation: Nature. 1965 Dec 25;208(5017):1341-2
references.pmid: 5870202
references.citation: J Pharm Biomed Anal. 2008 May 12;47(1):114-25
references.pmid: 18242038
references.citation: Environ Int. 2014 Mar;64:17-27
references.pmid: 24361922
references.citation: J Nucl Med. 2000 Jan;41(1):183-8
references.pmid: 10647622
references.citation: Int Immunopharmacol. 2003 Jun;3(6):889-900
references.pmid: 12781705
references.citation: Chemosphere. 2010 Jul;80(5):519-24
references.pmid: 20466404
references.citation: J Environ Manage. 2001 Jan;61(1):51-9
references.pmid: 11381458
references.citation: Calcif Tissue Int. 1990 Sep;47(3):136-41
references.pmid: 2224588
references.citation: Nature. 1967 Dec 9;216(5119):1005-7
references.pmid: 6072965
references.citation: Sci Total Environ. 2003 Dec 30;317(1-3):235-55
references.pmid: 14630424
references.citation: Ann N Y Acad Sci. 2009 Nov;1181:5-30
references.pmid: 20002040
references.citation: Blood. 1969 Nov;34(5):610-32
references.pmid: 5260601
references.citation: J Nutr. 1999 Sep;129(9):1731-6
references.pmid: 10460212
references.citation: Lancet. 1987 Jul 18;2(8551):160-1
references.pmid: 2885623
references.citation: Health Phys. 2010 Sep;99(3):420-9
references.pmid: 20699707