Photodynamic effect of argon and diode laser on cholesteatoma cell cultures after intravital staining with absorption enhancers

The Viability and Growth of HaCaT Cells After Exposure to Bioactive Glass S53P4-Containing Cell Culture Media

HYPOTHESIS

Bioactive glass (BG) S53P4 reduces the viability of epidermal keratinocyte-derived immortalized cell line, HaCaT in sufficient concentrations in vitro.

BACKGROUND

Although used in mastoid obliteration surgery, there is no data available on whether BG S53P4 granules have an inhibitory or excitatory effect on keratinocytes, found in normal skin and ear cholesteatoma in vivo.

METHODS

HaCaT cell cultures were incubated with a direct BG S53P4 granule contact. Microscopic evaluation of the cultures was performed and interleukin-6 (IL-6) and -8 (IL-8) concentrations were measured from the medium samples. In addition, BG granules were incubated in two cell culture media for 6 days and the pure media were used in confluent HaCaT cultures preceding cell viability assay. Finally, a scratch assay test was performed to reveal the possible BG effect on HaCaT cultures.

RESULTS

Eight to ten cell thick layers of dead HaCaT cells were noticed after a 2-day BG granule contact. With a BG concentration of 2.5%, IL-6 and IL-8 concentrations were smaller compared with the control group without BG after 2 days' incubation. Overall, HaCaT cell viability decreased when BG was incubated in keratinocyte growth medium, but did not change in Dulbecco's modified Eagle's medium. In a scratch assay test, cell regrowth in the scratch area was notable in cultures without BG.

CONCLUSIONS

BG S53P4 seems to have an inhibitory effect on HaCaT cell growth. Although further studies are needed, this observation seems advantageous for cholesteatoma treatment.

Mathematical models of laser-induced tissue thermal damage

Laser sources are under increasing study for in vivo tumour ablation. Photo-thermal ablation in tissues varies tremendously in governing physical phenomena, depending on wavelength, owing to wide variation in the optical properties of tissues, specifically the dominant chromophore and degree and type of scattering. Once converted into local tissue heating, however, the governing thermodynamic principles remain the same. Observed irreversible thermal alterations range from substantial structural disruption due to steam evolution in high temperature short-term activations to low temperature rise, longer-term initiation of the complex protein cascades that result in apoptosis and/or necroptosis. The usual mathematical model in hyperthermia studies, the thermal isoeffect dose, arising from the relative reaction rate formulation, is not an effective description of the higher temperature effects because multiple processes occur in parallel. The Arrhenius formulation based on the theory of absolute reaction rates is much more useful and descriptive in laser heating since the multiple thermodynamically independent processes may be studied separately.