Relative variation to received dose of some erythrocytic and leukocytic indices of human blood as a result of low-level laser radiation: an in vitro study.

OBJECTIVE: This study investigated the in vitro effects of low-level laser radiation (LLLR) on selected rheologic constants of the human blood. The variations of CBC parameters to the received dose were determined, as well as of blood viscosity (an erythrocyte aggregation index), as a research method for some structural alteration of blood proteins. This was also confirmed by the electrophoretic study of plasma proteins from the irradiated blood. METHODS: Fresh blood samples (whole blood) from 16 adult regular blood donors were irradiated with a He-Ne laser (lambda = 632.8 nm; power output = 6 mW; mean irradiance on blood samples approximately 180 mW.cm-2; beam spot diameter approximately 2 mm), operating in continuous wave. Doses ranged between 0 (control sample) and 9.346 J.cm-3.EDTA (for CBC and viscosity measurements) or citrate (for electrophoresis) anticoagulant was used. Measurements were performed before (control samples) and after irradiation. In most of the cases, the measurements were made immediately after irradiation. In some cases, the measurements were made after 24 or 48 h after irradiation, respectively, to conclude whether the modifications caused from irradiation occur in time, or immediately after irradiation. RESULTS: Following irradiation, marked variations of some erythrocyte and leukocyte indices and changes of the erythrocyte aggregation (viscosity), as a function of received dose, were observed. Significant differences between control and irradiated blood samples were found for the following rheologic factors: RBC (in 22.2% of cases); HGB (26.8%); HCT (82.4%); MONO and GRAN (36.7%); viscosity (82.5%). From the plasma proteins: albumin (22.2%); alpha 1 globulin and gamma globulin (18.5%); fibrinogen (70.4%). In most of the cases, remarkable effects (maxima) were noticed around 1.2 J.cm-3 dose value. We consider this dose value as optimal, one that can lead to beneficial effects. The cell membrane integrity was not affected from irradiation, for doses between 0 and 9.346 J.cm-3, and will probably not even be affected at higher doses (see MCV and MCHC behavior). CONCLUSIONS: The effect of LLLR on red blood cells confirms the nonresonant mechanism of this biostimulating effect, by the changes occurring in the cell membrane (in our case, blood cells), by revitalizing of red blood cell functional capacities and by several biochemical effects at the membrane's level. These are to be studied thoroughly in future studies. The physical-biochemical and biological effects caused by LLLR on blood can influence the physical-chemical parameters needed for the long-term storage of blood products. These effects can also lead to a quicker revitalization of the erythrocyte membrane (which was subjected to the action of some physical and biochemical factors during the preservation process), to perform its oxyphoric function in transfusion procedures.

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 effects of low-level laser radiation (LLLR) on some rheological factors of the human blood, such as complete blood count (CBC) parameters and blood sedimentation rate (BSR). We were mainly concerned with the alterations caused by LLLR action on blood cells (erythrocytes and leukocytes) of fresh blood obtained from apparently healthy adult patients. We used low doses ranging between 0.80 J x cm(-3) and 4.40 J x cm(-3), at the very low-power densities of the laser radiation, so as not to damage the cell structure and not to alter in an undesired manner their functions. METHODS: Blood samples were taken from 22 volunteers. Where health problems existed, they were indicated for each case. The parameters mentioned above were measured before (control samples) and after irradiation. A He-Ne laser, operating in continuous wave, as a radiation source (632.8 nm, 1 mW, intensity of 8 x 10(-2) W x sr(-1), mean power density incident on blood samples around 30 mW x cm(-2), beam spot diameter 2 mm) was used. The measurements were performed immediately after irradiation. Only the erythrocyte complex was irradiated. EDTA anticoagulant was used. RESULTS: The measurements using a computerized hemoanalyzer type SERONO showed significant differences between control and irradiated blood samples 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 differences were noticed especially in the cases of patients suffering from some acute or chronic diseases. Nonsignificant differences were noticed in the cases of MCV, MCH, MCHC, RDW, and LYMPH. CONCLUSIONS: This study has shown that LLLR, even though used at low doses and low power densities, produced some changes of the rheological factors of the blood, as follows: a revitalizing and regenerating effect on mitosis stimulation and a nondamaging and biostimulating 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 certain environmental physical factors.