Neutrophil response to Porphyromonas gingivalis is modulated by low‐level laser application

Objectives Neutrophil response is critical in inflammatory regulation and immune response to bacterial infections. During periodontal disease, pathogenic bacteria lead to exaggerated neutrophil responses. We hypothesized that low‐level laser application (LLLT), therapeutic strategy for dampening inflammatory processes, will regulate neutrophil activity in response to periodontopathogens. Materials and Methods The impact of LLLT on neutrophil responses was measured by light delivered at wavelength of 850 nm. The direct effect of LLLT on P. gingivalis A7436 was determined by flow cytometry using LIVE/DEADTM Cell Vitality kit. The phagocytosis of P. gingivalis A7436 by human neutrophils was measured using flow cytometry. Superoxide generation was measured by cytochrome‐C‐reduction in the presence of N‐formyl‐L‐methionyl‐L‐leucyl‐L‐phenylalanine (fMLP; 1 mM). Cytokine release by neutrophils was measured by multiplex immunoassay. Results The phagocytosis of P. gingivalis by primary human neutrophils was significantly reduced in response to LLLT (p