Effect of low‐power laser irradiation on cell growth and procollagen synthesis of cultured fibroblasts

Abstract

Background and Objectives In dentistry, low‐power lasers have been used in the treatment of dentin hypersensitivity, gingivitis, periodontitis, and different forms of oral ulcers. This in vitro study focuses on the biostimulation of NIH‐3T3 fibroblasts by a low‐power Ga–As‐pulsed laser. Study Design/Materials and Methods We have studied cell growth and procollagen synthesis of cultured fibroblasts submitted to low‐power laser irradiation with energy densities varying from 3 to 5 J/cm² over a period of 1–6 days. The light source was a 120 mW Ga–As diode laser (λ = 904 nm). Growth curves and procollagen immunoprecipitation were obtained. Results Irradiation of 3 and 4 J/cm² increased the cell numbers about threefold to sixfold comparing to control cultures. However, this effect was restricted to a small range of energy densities since 5 J/cm² had no effect on cell growth. The energy density of 3 J/cm² remarkably increased cell growth, with no effect on procollagen synthesis, as demonstrated by the immunoprecipitation analysis. Conclusions Our results showed that a particular laser irradiation stimulates fibroblast proliferation, without impairing procollagen synthesis. Lasers Surg. Med. 31:263–267, 2002.