Study of the action mechanisms of Arnica montana effects on macrophages

Abstract

Objective: To test the effect of Arnica montana (Arnica m.) on human macrophages. Method: The human monocytic leukaemia cell line THP-1 was cultured and differentiated in mature macrophages with PMA and other differentiating agents. Macrophages were exposed to Arnica m. homeopathic dilutions (2c, 3c, 5c, 9c and 15c) or Control solvent. Total RNA was isolated and sequenced to perform quantitative evaluation. Results: Screening sorted out with a list of 20 genes that were significantly changed by Arnica m. 2c treatment: 7 up-regulated and 13 down-regulated. Most notably, a clearly up-regulated function concerned the proteinaceous extracellular matrix (ECM), including genes HSPG2, FBN2, FN1 (p<0.01). The down-regulated genes converge into the common pathway of oxidative phosphorylation and particularly into the cell component gene ontology of mitochondrial complex I (p<0.001). Higher Arnica m. dilutions were effective also by upregulating the same geneset in cells treated with LPS but not in resting cells. Conclusion: In synthesis, we have identified a group of genes that are upregulated by Arnica m. in macrophages and many of them are involved in the processes of connective tissue remodelling and regeneration.