Synthesis of dental matrix proteins and viability of odontoblast-like cells irradiated with blue LED

Abstract

To evaluate the effect of irradiation with light-emitting diode (LED; 455 nm) on the viability and synthesis of dentin matrix proteins by odontoblast-like cells, MDPC-23 cells were cultivated (10(4) cells/cm(2)) in 24-well culture plates. After 12 h incubation in Dulbecco's modified Eagle's medium (DMEM), the cells were submitted to nutritional restriction by means of reducing the concentration of fetal bovine serum (FBS) for an additional 12 h. Cells were irradiated one single time with one of the following energy densities (EDs): 0.5, 2, 4, 10, or 15 J/cm(2) and irradiance fixed at 20 mW/cm(2). Non-irradiated cells served as control. After 72 h, cells were evaluated with regard to viability (methylthiazol tetrazolium technique (MTT)), mineralization nodule (MN) formation, total protein (TP) production, alkaline phosphatase activity (ALP), and collagen synthesis (Sircol), n = 8. The data were submitted to Kruskal-Wallis and Mann-Whitney tests (p > 0.05). There was no statistical difference between the viability of cells irradiated or not (control), for all the EDs. However, an increase in TP was observed for all the EDs when compared with the control group. A reduced ALP activity was seen in all irradiated groups, except for the ED of 0.5 J/cm(2), which did not differ from the control. There was no difference between the irradiated groups and control regarding collagen synthesis, with the exception of the ED of 10 J/cm(2), which inhibited this cell function. Significant reduction in MN occurred only for the EDs of 0.5 and 2 J/cm(2). The single irradiation with blue LED (455 nm), irradiance of 20 mW/cm(2), and energy densities ranging from 0.5 to 15 J/cm(2) exerted no effective biostimulatory capacity on odontoblast-like cells.

The biological effects of different LED wavelengths in the health field. A review

“…In another study, the blue LED was also applied to verify the viability and synthesis of dentin matrix proteins by odontoblast-like cells. The protocol used consisted in a single application using equipment with an intensity of 20 mW/cm and a dose of light equivalent to 0.5, 2, 4, 10, or 15 J/cm 2 and it was observed that blue LED did not present bio stimulatory capacity on odontoblast-like cells 45 .…”

Photobiomodulation effect of red LED (630 nm) on the free radical levels produced by pulp cells under stress conditions

“…Cell viability was determined using the methyl tetrazolium assay (tetrazoline 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyl bromide), which determines the activity of succinic dehydrogenase (i.e., a measure of cellular (mitochondrial) respiration) and represents the rate of viability. This well-standardized protocol has been previously described in detail [2,18,20,30].…”

“…Different modalities of photobiomodulation have been employed as adjuvant treatments for bone loss, myalgia, skin burns, spinal cord injury, and pulp repair [6][7][8][9][10]. Clinical and laboratory studi es have evaluat ed the eff ect of photobiomodulation on the healing of different tissues, such as the muscle and cartilage [11,12], neuronal cells [13,14], bone [15,16], and the dentin-pulp complex [2,17,18]. Photobiomodulation using light emitting diodes (LED) has been widely assessed in dentistry and is considered a potential adjuvant treatment for stimulating pulpal healing [2,[18][19][20][21][22][23].…”

“…Clinical and laboratory studi es have evaluat ed the eff ect of photobiomodulation on the healing of different tissues, such as the muscle and cartilage [11,12], neuronal cells [13,14], bone [15,16], and the dentin-pulp complex [2,17,18]. Photobiomodulation using light emitting diodes (LED) has been widely assessed in dentistry and is considered a potential adjuvant treatment for stimulating pulpal healing [2,[18][19][20][21][22][23]. LED irradiation with either infrared or red light enhances the proliferation of human and rodent pulp cells [21][22][23] as well as cultured odontoblast-like cells [2].…”