Silicea terra and Zincum metallicum Modulate the Activity of Macrophages Challenged with BCG In Vitro

Abstract

Abstract Background The homeopathic medicines Silicea terra (Sil) and Zincum metallicum (Zinc) modulate macrophage activity and were assessed in an experimental study in-vitro for their effects on macrophage–BCG (Bacillus Calmette–Guérin) interaction. Methods RAW 264.7 macrophages were infected with BCG, treated with different potencies of Sil and Zinc (6cH, 30cH and 200cH) or vehicle, and assessed 24 and 48 h later for bacilli internalization, hydrogen peroxide (H2O2) and cytokine production, and lysosomal activity. Results Treatment with vehicle was associated with non-specific inhibition of H2O2 production to the levels exhibited by uninfected macrophages. Sil 200cH induced significant reduction of H2O2 production (p < 0.001) compared with the vehicle and all other treatments, as well as higher lysosomal activity (p ≤ 0.001) and increased IL-10 production (p ≤ 0.05). Such effects were considered specific for this remedy and potency. The number of internalized bacilli was inversely proportional to Zinc potencies, with statistically significant interaction between dilution and treatment (p = 0.003). Such linear-like behavior was not observed for Sil dilutions: peak internalization occurred with the 30cH dilution, accompanied by cellular degeneration, and IL-6 and IL-10 increased (p ≤ 0.05) only in the cells treated with Sil 6cH. Conclusion Sil and Zinc presented different patterns of potency-dependent effect on macrophage activity. Bacterial digestion and a balanced IL-6/IL-10 production were related to Sil 6cH, though reduced oxidative stress with increased lysosomal activity was related to Sil 200cH. Degenerative effects were exclusively related to Sil 30cH, and potency-dependent phagocytosis was related only to Zinc.