Results and discussion

With the help of qPCR the expression levels of genes for MMP-1, MMP-2, MMP-12 and FOS-like antigen 1 (FOSL1) were analysed. The detection was done on HaCaT cell lines before and after low-intensity laser irradiation.

The authors observed that the expression of genes for MMP-1, MMP-2, and MMP-12 2 hours after low-intensity laser irradiation was significantly decreased compared with the control sample. At 6 hours after exposure, the expression of genes for MMP-1, -2, and -12 increased. At 24 hours after the procedure the authors detected the multidirection of gene expression (Figures 1–3).

Figure 1. Changes of MMP-1 gene expression on HaCaT cell line after low-intensity laser irradiation, 1270 nm. κ — control; 1m-2 — laser irradiation exposure time for 1 minute and 2 hours cultivation; 1m-6 — laser irradiation exposure time for 1 minute and 6 hours cultivation; 1m-24 — laser irradiation exposure time for 1 minute and 24 hours cultivation; 5m-2 — laser irradiation exposure time for 5 minutes and 2 hours; 5m-24 — laser irradiation exposure time for 5 minutes and 24 hours cultivation

Figure 1. Changes of MMP-1 gene expression on HaCaT cell line after low-intensity laser irradiation, 1270 nm. κ — control; 1m-2 — laser irradiation exposure time for 1 minute and 2 hours cultivation; 1m-6 — laser irradiation exposure time for 1 minute and 6 hours cultivation; 1m-24 — laser irradiation exposure time for 1 minute and 24 hours cultivation; 5m-2 — laser irradiation exposure time for 5 minutes and 2 hours; 5m-24 — laser irradiation exposure time for 5 minutes and 24 hours cultivation

Figure 2. Changes of MMP-2 gene expression on HaCaT cell line after low-intensity laser irradiation resurfacing with wavelengths 1270 nm. κ — control; 1m-2 — laser irradiation exposure time for 1 minute and 2 hours cultivation; 1m-6 — laser irradiation exposure time for 1 minute and 6 hours cultivation; 1m-24 — laser irradiation exposure time for 1 minute and 24 hours cultivation; 5m-2 — laser irradiation exposure time for 5 minute and 2 hours; 5m-24 — laser irradiation exposure time for 5 minute and 24 hours cultivation

Figure 2. Changes of MMP-2 gene expression on HaCaT cell line after low-intensity laser irradiation resurfacing with wavelengths 1270 nm. κ — control; 1m-2 — laser irradiation exposure time for 1 minute and 2 hours cultivation; 1m-6 — laser irradiation exposure time for 1 minute and 6 hours cultivation; 1m-24 — laser irradiation exposure time for 1 minute and 24 hours cultivation; 5m-2 — laser irradiation exposure time for 5 minute and 2 hours; 5m-24 — laser irradiation exposure time for 5 minute and 24 hours cultivation

Figure 3. Changes of MMP-12 gene expression on HaCaT cell line after low-intensity laser radiation resurfacing with wavelengths 1270 nm. κ — control; 1m-2 — laser irradiation exposure time for 1 minute and 2 hours cultivation; 1m-6 — laser irradiation exposure time for 1 minute and 6 hours cultivation; 1m-24 — laser irradiation exposure time for 1 minute and 24 hours cultivation; 5m-2 — laser irradiation exposure time for 5 minute and 2 hours; 5m-24 — laser irradiation exposure time for 5 minute and 24 hours cultivation

Figure 3. Changes of MMP-12 gene expression on HaCaT cell line after low-intensity laser radiation resurfacing with wavelengths 1270 nm. κ — control; 1m-2 — laser irradiation exposure time for 1 minute and 2 hours cultivation; 1m-6 — laser irradiation exposure time for 1 minute and 6 hours cultivation; 1m-24 — laser irradiation exposure time for 1 minute and 24 hours cultivation; 5m-2 — laser irradiation exposure time for 5 minute and 2 hours; 5m-24 — laser irradiation exposure time for 5 minute and 24 hours cultivation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

At 2 hours after low-intensity laser irradiation the expression of genes for MMP-1, -2, and -12 was significantly decreased compared with the control sample.

There is no correlation between the duration of exposure time (1 or 5 minutes) and effect of laser irradiation on keratinocytes. The comparison was carried out after 2 hours of cultivation. In both cases the expression level of genes for MMP-1, -2, and -12 was decreased. Therefore, findings show that there is no significant correlation between changes in gene expression and exposure time. As the decrease of expression levels start almost after exposure, and it is a rapid response to laser irradiation, it is possible to assume that the most objective data results occur after 2 hours of cell cultivation.

It is possible the prolongation of the cultivation period after laser exposure cannot illustrate cell response to radiation objectively owing to the fact that cultivated cells are taken from the human immune system.

The increase of MMP expression can be explained by the fact that MMPs are triggers for MAP-kinase pathways, oxidant and nitrate stress, caspase cell death, excitotoxicity, and neuroinflammation15, 16.

The change of gene expression in keratinocytes before and after low-intensity laser irradiation correlates with the effect of laser therapy in clinical practice. Intravenous blood irradiation is a government-certified physiotherapeutic method for treatment of psoriasis in Russia. The authors observed the effect of intravenous blood irradiation with the same laser radiation properties in patients with psoriasis vulgaris. At 2–3 days after the procedure the stimulation of the pathological process of the skin was shown. The main symptoms were oedema of the plaques and the appearance of new papules. Nevertheless, after three or four procedures the authors observed the regression of the plaques and remission expanded from 6 months to 18 months.

Conclusions

The results of this study can illustrate the effectiveness of laser radiation with a wavelength of 1270 nm in the treatment of psoriasis.