Effect of low power lasers on prokaryotic and eukaryotic cells under different stress condition: a review of the literature

Assessment of DNA mutagenicity induced by He-Ne laser using Salmonella typhimurium strains

Helium-neon (He-Ne) laser mutagenesis is widely used in microbiology and plant breeding. In this study, two frameshift mutant representative strains of Salmonella typhimurium TA97a and TA98 and two base pair substitution types TA100 and TA102 were employed as model microorganisms to assess DNA mutagenicity induced by He-Ne laser (3 J·cm^-2·s^-1, 632.8 nm) for 10, 20, and 30 min. The results revealed that the optimal laser application was 6 h in the mid-logarithmic growth stage. Low-power He-Ne laser for short treatment inhibited cell growth, and continued treatment stimulated the metabolism. The effects of the laser on TA98 and TA100 were the most prominent. Sequencing results from 1500 TA98 revertants showed that there were 88 insertion and deletion (InDel) types in the hisD3052 gene, of which the InDels unique to laser were 21 more than that of the control. Sequencing results from 760 TA100 revertants indicated that laser treatment created Pro (CCC) in the product of the hisG46 gene more likely to be replaced by His (CAC) or Ser (TCC) than by Leu (CTC). Two unique non-classical base substitutions, CCC → TAC and CCC → CAA, also appeared in the laser group. These findings will provide a theoretical basis for further exploration of laser mutagenesis breeding. KEY POINTS: • Salmonella typhimurium served as model organism for laser mutagenesis study. • Laser promoted the occurrence of InDels in the hisD3052 gene of TA98. • Laser promoted the occurrence of base substitution in the hisG46 gene of TA100.

Laser Needle Knife's Effects on Rabbits Cervical Spondylopathy of Vertebral Artery, Fibrinogen, and Blood Viscosity

Objective

To determine the effect of laser needle-knife on vertebroarterial morphology, fibrinogen and blood viscosity in a rabbit model of cervical spondylotic arteriopathy (CSA) and the mechanism of action involved.

Methods

A number of 40 healthy common grade rabbits were divided into four groups: normal control, model, acupuncture, and laser needle knife group. The normal control group does not establish a CSA rabbit model, and the other groups all establish a CSA rabbit model, but they are treated in different ways. CSA model rabbits were treated with acupuncture and moxibustion at “fengchi” and “cervical Jiaji” points, rabbits in the laser needle knife group were treated with “Jiaji” points, and the acupuncture points were punctured with the laser needle knife. The location of the acupuncture points is determined according to the acupoint map of the experimental map. The right vertebroarterial morphology before and after the treatment was analyzed by scanning electron microscope, and FIB concentration and blood viscosity were determined using the coagulation method.

Results

After the treatment, the capillary and micropore hyperplasia in the laser needle knife group were more evident than that in the model group. Acupuncture and laser needle knife therapy can reduce whole blood viscosity (1/s, 5/s), and that the distinction between the two treatments is not statistically evident.

Conclusion

Acupuncture and laser needle knife can regulate the coagulation and fibrinolysis system in CSA, stimulate capillary and micropore hyperplasia, reduce blood viscosity, and improve blood circulation, which may be one of the therapeutic mechanisms behind the laser needle knife treatment of CSA.