Comparative In Vitro Study: Examining 635 nm Laser and 265 nm Ultraviolet Interaction with Blood

Objective: This study represents a viable assessment of the effect of the low-level laser (LLL) of 635 nm and ultraviolet (UV) of 265 nm on biophysical properties of blood. Materials and methods: Blood samples were divided into two main groups: one for irradiation by LLL and the other for irradiation by UV. Each group was divided into three aliquots. First aliquot: whole blood was exposed to radiation. The second aliquot: erythrocytes were exposed to radiation and resuspended in autologous plasma. The third aliquot: plasma was exposed to radiation, and erythrocytes were resuspended in it. The following parameters were measured after irradiation by LLL and UV for all aliquots: whole blood viscosity, microscopic aggregation index, deformation index, and Zeta potential. Results: A decrease in whole blood viscosity due to irradiation by LLL was observed. To the contrary, an increase in whole blood viscosity due to irradiation by UV was detected. A significant reduction in erythrocytes' aggregation was observed as a result of LLL and UV radiation. Erythrocytes' deformability was strongly affected by UV radiation, while there was no significant effect from LLL. Another noticeable change observed was an increase in Zeta potential due to UV and a decrease in Zeta potential values, as a result of LLL irradiation. Conclusions: It can be concluded from this study that LLL and UV can be used to change some biological processes, as well as cellular properties.

Erythrocyte sedimentation rate of human blood exposed to low-level laser

This study is designed to investigate in vitro low-level laser (LLL) effects on rheological parameter, erythrocyte sedimentation rate (ESR), of human blood. The interaction mechanism between LLL radiation and blood is unclear. Therefore, research addresses the effects of LLL irradiation on human blood and this is essential to understanding how laser radiation interacts with biological cells and tissues. The blood samples were collected through venipuncture into EDTA-containing tubes as an anticoagulant. Each sample was divided into two equal aliquots to be used as a non-irradiated sample (control) and an irradiated sample. The aliquot was subjected to doses of 36, 54, 72 and 90 J/cm(2) with wavelengths of 405, 589 and 780 nm, with a radiation source at a fixed power density of 30 mW/cm(2). The ESR and red blood cell count and volume are measured after laser irradiation and compared with the non-irradiated samples. The maximum reduction in ESR is observed with radiation dose 72 J/cm(2) delivered with a 405-nm wavelength laser beam. Moreover, no hemolysis is observed under these irradiation conditions. In a separate protocol, ESR of separated RBCs re-suspended in irradiated plasma (7.6 ± 2.3 mm/h) is found to be significantly lower (by 51 %) than their counterpart re-suspended in non-irradiated plasma (15.0 ± 3.7 mm/h). These results indicate that ESR reduction is mainly due to the effects of LLL on the plasma composition that ultimately affect whole blood ESR.

In Vitro Mean Red Blood Cell Volume Change Induced by Diode Pump Solid State Low-Level Laser of 405 nm

OBJECTIVE

This study was conducted to investigate the effects of low-level laser (LLL) doses on human red blood cell volume. The effects of exposure to a diode pump solid state (DPSS) (λ = 405 nm) laser were observed.

BACKGROUND DATA

The response of human blood to LLL irradiation gives important information about the mechanism of interaction of laser light with living organisms. Materials and methods Blood samples were collected into ethylenediaminetetraacetic acid (EDTA)-containing tubes, and each sample was divided into two equal aliquots, one to serve as control and the other for irradiation. The aliquot was subjected to laser irradiation for 20, 30, 40, or 50 min at a fixed power density of 0.03 W/cm(2). Mean cell volume (MCV) and red blood cell (RBC) counts were measured immediately after irradiation using a computerized hemtoanalyzer.

RESULTS

Significant decrease in RBC volume (p < 0.05, p < 0.0001, p < 0.0001, and p < 0.05, respectively) was induced with variation in laser doses.The highest response was observed with an exposure time of 40 min. This result was reproduced in RBCs suspended in a buffered NaCl solution. In contrast to this finding, laser-induced RBC volume change was completely abolished by suspending RBCs in a solution containing a higher concentration of EDTA.

CONCLUSIONS

It was suggested that LLL can reduce RBC volume possibly because of the increased free intracellular Ca(+2) concentrations, which activate Ca(+2)-dependent K(+) channels with consequent K(+) ion efflux and cell shrinkage.