Effect of low-level laser radiation on some rheological factors in human blood: An in vitro study

Objective: The purpose of this study was to investigate the in vitro effect s of low-level laser radiation (LLLR) on some rheological factors of the hu man blood, such as complete blood count (CBC) parameters and blood sediment ation rate (BSR). We were mainly concerned with the alterations caused by L LLR action on blood cells (erythrocytes and leukocytes) of fresh blood obta ined from apparently healthy adult patients. We used low doses ranging betw een 0.80 J.cm(-3) and 4.40 J.cm(-3), at the very low-power densities of the laser radiation, so as not to damage the cell structure and not to alter i n an undesired manner their functions. Methods: Blood samples were taken fr om 22 volunteers. Where health problems existed, they were indicated for ea ch case. The parameters mentioned above were measured before (control sampl es) and after irradiation. A He-Ne laser, operating in continuous wave, as a radiation source (632.8 nm, 1 mW, intensity of 8.10(-2) W.sr(-1), mean po wer density incident on blood samples around 30 mW.cm(-2), beam spot diamet er 2 mm) was used. The measurements were performed immediately after irradi ation. Only the erythrocyte complex was irradiated. EDTA anticoagulant was used. Results: The measurements using a computerized hemoanalyzer type SERO NO showed significant differences between control and irradiated blood samp les concerning the following parameters: RBC (in 22% of cases), HGB (47.3%) , HCT (84.2%), RDW (11%), PLT (5.26%), MPV (33.3%), WBC (5.26 %), MONO (26. 3 %), and GRAN (63.15 %). In the case of BSR (44 %), the significant differ ences were noticed especially in the cases of patients suffering from some acute or chronic diseases. Nonsignificant differences were noticed in the c ases of MCV, MCH, MCHC, RDW, and LYMPH. Conclusions: This study has shown t hat LLLR, even though used at low doses and low power densities, produced s ome changes of the rheological factors of the blood, as follows: a revitali zing and regenerating effect on mitosis stimulation and a nondamaging and b iostimulating effect on the cell membrane (by keeping unmodified MCV, MCH, and MCHC). In 3 cases out of 22, hemolysis (complete or partially) occurred , but we are not yet sure whether this was caused by laser exposure or by c ertain environmental physical factors.