title: Inhibition of human in vitro osteoclastogenesis by Equisetum arvense.
abstract: OBJECTIVE
  Equisetum arvense has long been used in traditional medicines to treat different disorders, including bone pathologies. In this study a hydromethanolic extract of E. arvense was assessed for its effects on human osteoclastogenesis.
  
  
  METHODS
  Osteoclast precursors were maintained in non-stimulated and stimulated (presence of M-CSF and RANKL) conditions, or in co-cultures with osteoblasts. Cell cultures were treated with 0.00016-0.5 mg/ml of a hydromethanolic E. arvense extract.
  
  
  RESULTS
  The extract did not affect spontaneous osteoclastogenesis. In osteoclast precursors committed to osteoclastogenesis (stimulated or co-cultured with osteoblasts), E. arvense caused dose-dependent inhibitory effect that became statistically significant at concentrations ≥0.004 mg/ml. This was observed using different osteoclast differentiation and activation markers. Cell response was associated with changes in relative contribution of MEK and NFkB signalling pathways, as well as PGE2 production. As there were differences in the response of osteoclast precursors maintained in the presence of inductive factors, or co-cultured with osteoblastic cells, it seems that E. arvense extract had the ability to modulate osteoclastogenesis, either by acting directly on osteoclast precursor cells, and/or via osteoblasts.
  
  
  CONCLUSIONS
  Equisetum appeared to have a negative effect on human osteoclastogenesis, which is in line with its putative beneficial role in pathophysiological conditions associated with increased osteoclastic activity, and might suggest potential utility for treatment with bone regeneration strategies.
authors.affiliation: Laboratory of Pharmacology and Cellular Biocompatibility, University of Porto, Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Costa-Rodrigues
authors.forename: S C
authors.initials: SC
authors.lastname: Carmo
authors.forename: J C
authors.initials: JC
authors.lastname: Silva
authors.forename: M H R
authors.initials: MH
authors.lastname: Fernandes
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000328:Adult; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism; D002478:Cells, Cultured; D018920:Coculture Techniques; D020829:Equisetum / Q000737:chemistry*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D053245:RANK Ligand / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D002130:Calcium Phosphates; D007527:Isoenzymes; D010936:Plant Extracts; D053245:RANK Ligand; D016173:Macrophage Colony-Stimulating Factor; C020243:calcium phosphate; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase