title: Chondroprotective effects of palmatine on osteoarthritis in vivo and in vitro: A possible mechanism of inhibiting the Wnt/β-catenin and Hedgehog signaling pathways.
abstract: The present study aimed to investigate the effect of palmatine (Pal) in a rabbit osteoarthritis (OA) model in vivo and rabbit interleukin-1β (IL-1β)-stimulated chondrocytes in vitro. Appropriate concentrations of Pal were identified by the MTT assay and used to preincubate IL-1β-induced chondrocytes, as well as an activator or inhibitor of Wnt and Hedgehog signaling pathways. Matrix metalloproteinase (MMP)-1, 3, and 13; tissue inhibitor of metalloproteinase (TIMP)-1; collagenase II; aggrecan; and the related molecules of the Wnt/β-catenin and Hedgehog signaling pathways were investigated. Protein expression was detected by Western blot analysis and messenger RNA (mRNA) expression was examined by PCR analysis. Pal (0.3 mL, 100 mg/L) was injected into rabbit knee joints and histological examination, immunohistochemistry, and Mankin scoring of the articular cartilage were performed. Pal (10-100 mg/L) had no effect on chondrocyte viability, decreased the expression of the MMPs, and increased the synthesis of TIMP-1whereas collagenase II and aggrecan were inhibited by IL-1β. When the activator (Licl) and inhibitor (DKK-1) of the Wnt/β-catenin signaling pathway as well as the inhibitor (cyclopamine) of the Hedgehog signaling pathway were added, the Wnt/β-catenin signaling pathway was less inhibited by Pal, and a similar inhibitory effect of cyclopamine on the Hedgehog signaling pathway was evident. Additionally, Pal enhanced the effect of cyclopamine. The histological examination, immunohistochemistry and Mankin scoring also demonstrated the protective effect of Pal, and the inhibition of the Wnt and Hedgehog signaling pathways by Pal. Pal may be useful in the treatment of OA, in which its effect is likely mediated via the Wnt/β-catenin and Hedgehog signaling pathways.
authors.affiliation: Department of Orthopedics Surgery, Affiliated Hospital of Nanjing Medical University, Changzhou Second People's Hospital, Changzhou 213003, China; Department of Orthopedics Surgery, The Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China. Electronic address: xindiezhou@yahoo.com.
authors.forename: Xindie
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Conservative Dentistry and Periodontics, Affiliated Hospital of Stomatology, College of Medicine, Zhejiang University, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Orthopedics Surgery, The Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Department of Orthopedics Surgery, The Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Orthopedics Surgery, The Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China.
authors.forename: Weijun
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Orthopedics Surgery, The Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Orthopedics Surgery, The Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China. Electronic address: ldwu@yahoo.com.
authors.forename: Lidong
authors.initials: L
authors.lastname: Wu
mesh_terms: D000818:Animals; D001600:Berberine Alkaloids / Q000627:therapeutic use*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000502:physiology; D004357:Drug Synergism; D006364:Hedgehogs / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D053583:Interleukin-1beta / Q000276:immunology; D018021:Lithium Chloride / Q000494:pharmacology; D020782:Matrix Metalloproteinases / Q000378:metabolism; D010003:Osteoarthritis / Q000188:drug therapy*; D011817:Rabbits; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism; D014703:Veratrum / Q000276:immunology; D014704:Veratrum Alkaloids / Q000494:pharmacology; D051153:Wnt Proteins / Q000378:metabolism*; D060449:Wnt Signaling Pathway / Q000187:drug effects; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D001600:Berberine Alkaloids; D036341:Intercellular Signaling Peptides and Proteins; D053583:Interleukin-1beta; D019715:Tissue Inhibitor of Metalloproteinase-1; D014704:Veratrum Alkaloids; D051153:Wnt Proteins; D051176:beta Catenin; D020782:Matrix Metalloproteinases; D018021:Lithium Chloride; C005413:palmatine; C000541:cyclopamine
keywords: Hedgehog signaling pathway; Interleukin-1β; Matrix metalloproteinase; Osteoarthritis; Palmatine; Wnt signaling pathway