Effects of Helium - Neon Laser Irradiation on Proliferation and collagen Synthesis by Human Dermal Fibroblasts Cultured in a Monolayer and Collagen Lattice

Suhr, Ki Beom; Yoon, So Young; Lee, Woo Jae; Lee, Jeung Hoon; Park, Jang Kyu

Abstract

BACKGROUND: Recently it has been suggested that lasers can modulate the biological functions of cells in vitro. It has also been reported that a helium-neon(He-Ne) laser can stimulate wound healing in the absence of thermal effects. However, the results of more recent studies on the influence of He-Ne laser irradiation on the proliferation and collagen synthesis of human dermal fibroblasts have been inconclusive. And most experiments have not been performed in a three-dimensional collagen lattice that is the physiologic model for an in vitro experiment.
OBJECTIVE
In this study we have investigated the nature of the influence of He-Ne laser irradiation on the proliferatior and collagen synthesis of human dermal fibroblasts cultured in a monolayer and collagen lattice.
METHODS
We used a 10mW He-Ne laser emitting a beam of wavelength 632,8nm. The human dermal fibroblasts were subjected to laser treatment at various energy densities, and the treatment schedule included one daily exposure on three consecutive days. DNA replication was assessed by H-thymidine incorporation, and the collagen production was monitored by the synthesis of H-hydroxyproline following incubation of the culture with H-proline.
RESULTS
The results were as follows : In the control group, the proliferation and collagen synthesis of fibroblasts sultured in a collagen lattice on day 4 and 7 were significantly reduced compared with conventional manolayer cultures. Although the proliferation of human dermal fibroblasts was not remarkable in all experimental irradiation energy except 4 J/cm in a monolayer culture, a statistically significant stimulating effect on fibroblasts proliferation in collagen lattice were noted on days 4 and 7 with an energy density of 1.5J/cm. And we also found that a great er increase of collagen synthesis of human dermal fibroblasts occurred in a monolayer culture on days 4 and 7 in all irradiated energy densities than those in a collagen lattice culture. But statistically significant enhancement of collagen synthesis was showed only at the energy density of 1 J/cm in a collagen lattice culture on days 4.
CONCLUSION
These data indicated that the influence of He-Ne laser irradiation on the proliferation and collagen synthesis of human dermal fibroblasts cultured in a collagen lattice was remark ably different from those in a monolayer culture. In the clinical application of the He-Ne laser, the control of the amount of irradiation of the He Ne laser may regulate the proliferative activity and collagen synthesis of human dermal fibroblasts in wound healing.