title: In vitro effects of helium-neon laser irradiation on human blood: blood viscosity and deformability of erythrocytes.
abstract: OBJECTIVE
  The purpose of this study was to investigate the in vitro effects of He-Ne laser irradiation on some rheological factors of human blood, such as blood viscosity, erythrocyte deformability, and sedimentation rate.
  
  
  BACKGROUND
  The intravascular irradiation of low power laser has been applied in pre-clinical and clinical to treat various pathological processes. However, the mechanism is not fully understood so far. Especially the interaction and related mechanism between the laser and blood are unclear. In this work, by measuring the change of the main rheological factors after laser irradiation, the interaction and mechanism were explored.
  
  
  METHODS
  A30-mW He-Ne laser was used for irradiation with a 4-5-mm-diameter beam spot on blood samples, with a fluence rate of about 150 mW/cm.(2) The irradiation time was 60 min, so the total dose of irradiation was 540 J/cm.(2) The pathological samples of blood were obtained from patients (volunteers), and each sample was divided into two tubes for irradiation and control. The blood viscosity, erythrocyte deformability, and sedimentation rate were measured after laser irradiation and compared with un-irradiated control. The blood samples with poor erythrocyte deformability were prepared by adding Ca(2+) to the normal erythrocytes of a healthy person for investigating the laser effect on erythrocyte deformability further.
  
  
  RESULTS
  Laser irradiation reduced the erythrocyte sedimentation rate of blood samples, which had a hyper-sedimentation rate originally. The blood viscosity of samples in hyper-values was lowered by laser irradiation in all shear rates measured (10-110 S(-1)), with a relative variation of approximately 10%. The deformability of erythrocytes from pathological samples and Ca(2+)-treated samples was improved after laser irradiation.
  
  
  CONCLUSIONS
  The positive effects of laser irradiation on improving the rheological properties of blood were demonstrated in vitro.
authors.affiliation: Department of Physics, State Key Laboratory of Applied Surface Physics, Fudan University, Shanghai, China.
authors.forename: Xian-Qiang
authors.initials: XQ
authors.lastname: Mi
authors.forename: Ji-Yao
authors.initials: JY
authors.lastname: Chen
authors.forename: Zi-Jun
authors.initials: ZJ
authors.lastname: Liang
authors.forename: Lu-Wei
authors.initials: LW
authors.lastname: Zhou
mesh_terms: D001799:Blood Sedimentation; D001809:Blood Viscosity / Q000528:radiation effects*; D004907:Erythrocyte Deformability / Q000528:radiation effects*; D006371:Helium; D006400:Hematocrit; D018056:Hemorheology / Q000528:radiation effects*; D006801:Humans; D007834:Lasers; D009356:Neon
chemical_list: D006371:Helium; D009356:Neon