Effects of Low-Level Laser Therapy on M1-Related Cytokine Expression in Monocytes via Histone Modification

Abstract EN

Low-level laser therapy (LLLT) has been used in the treatment of radiotherapy-induced oral mucositis and allergic rhinitis.

However, the effects of LLLT on human monocyte polarization into M1 macrophages are unknown.

To evaluate the effects of LLLT on M1-related cytokine and chemokine production and elucidate the mechanism, the human monocyte cell line THP-1 was treated with different doses of LLLT.

The expression of M1-related cytokines and chemokines (CCL2, CXCL10, and TNF-α) was determined by ELISA and real-time PCR.

LLLT-associated histone modifications were examined by chromatin immunoprecipitation (ChIP) assays.

Mitochondrial involvement in the LLLT-induced M1-related cytokine expression was evaluated by quantitative real-time PCR.

Flow cytometry was used to detect the cell surface markers for monocyte polarization.

The results showed that LLLT (660 nm) significantly enhanced M1-related cytokine and chemokine expression in mRNA and protein levels.

Mitochondrial copy number and mRNA levels of complex I-V protein were increased by LLLT (1 J/cm2).

Activation of M1 polarization was concomitant with histone modification at TNF-α gene locus and IP-10 gene promoter area.

This study indicates that LLLT (660 nm) enhanced M1-related cytokine and chemokine expression via mitochondrial biogenesis and histone modification, which may be a potent immune-enhancing agent for the treatment of allergic diseases.