Effect of low-intensity laser on gene and protein expression of different phenotypes of macrophages

Abstract

The interactions between tissue and macrophages that invade after an injury happens are crucial to the evolution of its repair. On the other hand, low intensity laser (LLLT) has been extensively used in the treatment of tissue damage in different clinical and experimental contexts; however, little is known about its effects on macrophages. The objectives of this project are to evaluate the effects of LLLT (2 dosimetric parameters) on gene expression and protein synthesis of 12 products (important in tissue repair) of activated/polarized macrophages (for phenotypes M1, M2a and M2C). Macrophage cultures will be activated/polarized for 24 hours, washed and irradiated with red laser (660 nm) and infrared (780 nm) in the same dosimetric parameters (70 mW, 17,5 J/cm2, 0,8J). Following incubation periods of 4 and 24 hours, PCR array analysis will be performed for gene expression of chemokines (cxcl2 (MIP-2a), ccl 2 (Mcp-1), ccl 3 (Mip-1a), ccl4 (Mip-1b)); cytokines (IL-1², IFN³, IL-6, TNF±, IL-13); and growth factors (TGF²1, IGF1 and Vegfa). Culture supernatant of the different experimental groups (after 24 hours of irradiation) will be used to assess protein production. In each experimental situation, non-irradiated and non-activated cells will serve as control. Three independent experiments will be conducted within each aforementioned methodology. All results will be analyzed statistically.