Effects of homeopathic Arnica montana on gene expression of human macrophages-results of quantitative real-time PCR

Introduction : Arnica montana is a plant belonging to the Compositae family and one of the most popular medications used in complementary and homeopathic medicine to treat inflammation, wounds, hematoma, contusion and pain. Recently has been pointed out the double role of the sesquirterpenic lactone helenalin in the inhibition of the transcription factor NF-KB directly targeting p65 and in the gene suppression of the same subunit. This study considers the changes due to different homeopathic dilutions in gene expression of several cytokines, chemokines and receptor by real-time PCR technique in monocyte/macrophage cellular model.

Methods : The effect of Arnica m. on gene modulation of human monocytes (THP-1 cell line) was analyzed with RT-ARRAY PCR technique. THP-1 cells differentiated into activated macrophages by phorbol-12-myristate-13-acetate (PMA) for 48 h were challenged with different homeopathic dilutions of Arnica m. (2c, 3c, 5c, 9c and 15c diluted/dynamized in water, with 0.03% ethanol final concentration) and with control solution (water with 0.03% ethanol). Drug-treated and untreated macrophages were incubated for 24 h in the absence and in the presence of 10 ng/ml E. Coli lipopolysaccharide (LPS). Total RNA was extracted and retro-transcribed into cDNA to quantify the relative amount of gene trascripts (SYBR Green dye) in treated cells respect to placebo (DDCt method).

Results and discussion : The treatments with Arnica m. homeopathic dilutions in cell cultures without LPS induced a significant changes in gene expression modulation for the CCL2 (Freg = −40%), IL-1B (Freg = −50%) and TNF-a (Freg = −25%), compared with vehicle solution. The effect was not linearly related to dilution/dynamization, showing a pattern of down-regulation genes in all dilutions tested, with the exception of 15c. Different patterns were observed in the presence of LPS, where only BMP2 gene resulted slightly up-regulated (Freg = +20%). Our findings are compatible with a mild modulation of inflammatory process by homeopathic dilutions/dynamizations of this plant, even if further studies are needed to clarify the molecular targets.