Curcumin improves age-related and surgically induced osteoarthritis by promoting autophagy in mice
Authors: Guowang Zhang
Bo Liang
Jiaqing Cao
Jianing Ding
Erzhu Yang
Jiaming Liang
Jianguang Xu
Journal: Bioscience Reports (2018)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Osteoarthritis; autophagy; curcumin.
Affiliations: Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China., Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China .

Abstract:  Reduced autophagy has been implied in chondrocyte death and osteoarthritis. Curcumin (Cur) owns therapeutic effect against osteoarthritis (OA) and enhances autophagy in various tumor cells. Whether the cartilage protection of curcumin is associated with autophagy promotion and the potential signaling pathway involved remains unclear. The present study aimed to investigate the role of autophagy in the anti-OA activity of curcumin using spontaneous and surgically induced OA mice model. Spontaneous and surgically induced OA mice model was established and treated with Cur. Articular cartilage destruction and proteoglycan loss were scored through Safranin O/Fast green staining. Apoptotic cell death was detected with TUNEL (terminal deoxynucleotidyl transferase-mediated dTUP-biotin nick end labeling assay) staining and Western blot for caspase-3, Bcl-2 associated X protein (Bax), and Bcl-2 (B-cell lymphoma-2). Light chain 3 (LC3) immunohistochemistry was used to evaluate autophagy. In vitro, primary chondrocytes were treated with interleukin 1 beta (IL-1β) and Cur. Autophagy was inhibited using 3-methyladenine. Apoptosis and autophagy were detected using flow cytometry and Western blotting assay. Curcumin treatment enhanced autophagy, reduced apoptosis, and cartilage loss in both OA models. In vitro, curcumin treatment improved IL-1β induced autophagy inhibition, cell viability decrease, and apoptosis. Mechanistically, in vivo studies suggested curcumin promoted autophagy through regulating Akt/mTOR pathway. In conclusion, our results demonstrate that curcumin-induced autophagy via Akt/mTOR signaling pathway contributes to the anti-OA effect of curcumin. 

Retracted: No

PubPeer comments:
 There appear to be a number of overlapping or repeated images between figures one and two. there may be more. I did not look elsewhere in this paper. Interestingly, this paper was on the list of u201cmost citedu201d papers by this journal. *** ![file] , 
 Fig 2 on its own: ![file] , 
 Combining #1 and #2 ![file] , 
 Interestingly, despite the remarkable amount of image concerns noted in this thread, this paper is purported to be one of the journalu2019s most highly cited papers. *** ![file] , 
 Expression of Concern: LncRNA DANCR promotes migration and invasion through suppression of LncRNA-LET in gastric cancer cells The Editorial Office has been made aware of potential issues surrounding the scientific validity of this paper, hence has issued an expression of concern to notify readers whilst the Editorial Office investigates. , 
 Retraction: LncRNA DANCR promotes migration and invasion through suppression of LncRNA-LET in gastric cancer cells This Retraction follows an Expression of Concern relating to this article previously published by Portland Press. This article is being retracted from Bioscience Reports at the request of the Editor in Chief and the Editorial Board following receipt of a notification from a reader, alerting the Editorial Board to duplication in the images used in Figures 1C, 1D, 1E, 1F, 2D and 2F. The authors were contacted regarding the concerns raised and have not responded. Given the concerns with the Figures, the Editorial Board stands by the decision to retract. , 
 #6 What does it tell us about the field that a farrago of fabrication was cited by 82 other papers? ,