It is considered that laser irradiation regulates signaling pathways that are involved in proliferation of trabecular cells. Such key regulators of the trabecular cells are members of the TGF-β family. The aim of the study was to evaluate the effect of different modes of laser irradiation after TGF-β2 treatment of different cell lines. In this study we used diode laser “Iridex diodе laser 810” (IRIDEX, СA, USA) in the regime (mode) of microimpulse and continuous modes at two different levels of power (22 impulses of 200 milliseconds each or continuous work for 22 seconds at 2,000 and 1,000 milliwats each) that are widely used in ophthalmology practice, such as laser microsurgery of eyes.

We exposed several cell lines to laser irradiation: BALB 3T3 (pseudonormal murine fibroblasts), L929 (transformed murine fibroblasts) and normal human fibroblasts obtained from human jaw-mouth cavity. Cell vitality was evaluated for the next 7 days after exposure to laser beams of different mode. The cell viability test and counting of cells (alive/dead ratio) was performed with the use of MikMed-12 light/luminescent microscope (trypan blue-staining test). To affirm the validity of the trypan blue staining test we performed a MTT test to evaluate the metabolic activity of the treated cell lines. An evaluation of modulation of the effect of laser towards the changes in the functional state we performed a detailed sample analysis of the connective tissue to measure the level of TGF-β2. Statistical processing of the obtained results was performed by using Student’s T-test, mean values, standard deviation and variation coefficient. Each experiment was repeated at least 3 times. The difference between the two variables was considered as reliable when the standard deviation “P” was less than 0.05.

It was found that laser irradiation did not affect proliferation activity and vitality of normal cells of the connective tissue. The above mentioned way of laser treatment of the transformed fibroblasts (L929) in culture of a dose of <0.1 Jole/cm2 dose no significant changes in stimulation of cell proliferation was observed, whereas combination of such dose of laser irradiation and TGF β2 treatment inhibited proliferation activity more in transformed murine fibroblasts (L929), comparing to pseudonormal murine fibroblasts (BALB 3T3). The effect of “Iridex 810” laser irradiation correlated with our previous results obtained after laser irradiation of mesenchymal cell lines by the He-Ne laser “Polaron” (LHN-102, Polaron, Lviv, USSR) in scan mode (λ=633 nm). The means of cell growth of pseudonormal murine fibroblasts (BALB 3T3) where greater then those of transformed murine fibroblasts (L929). Such difference can be due to the different level of transformation of the treated cell lines.

The above proposed model describes how cells of the trabecular tissue communicate with each other after exposure to scleroticectomy. These processes take place during laser trabeculoplasty might be of great importance for further improvement of glaucoma treatment. Results obtained from this study also might contribute to better understanding of the processes involved in cancerogenesis after laser irradiation. As a conclusion it can be stated, that laser treatment can be considered as a safe and reliable way of tissue treatment. We observed a low susceptibility of the pseudonormal fibroblasts of the connective tissue comparing to malignant transformed cells. Further studies in this expanding field that might shed light towards explaining the action of lasers of different mode and its anticancer effect in chemotherapy. Further studies are in progress.

Ключові слова: diode laser, 810 nm wave length, fibroblasts, TGF β, cytomorphological characteristics, МТТ test

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