title: Shikonin protects chondrocytes from interleukin-1beta-induced apoptosis by regulating PI3K/Akt signaling pathway.
abstract: Chondrocyte apoptosis is mostly responsible for the development and progression of osteoarthritis. IL-1β is generally served as an agent that induces chondrocyte apoptosis. Shikonin exerts its anti-inflammatory effect on cartilage protection in vivo. We aimed to explore the protective effect of shikonin on interleukin-1beta (IL-1β)-induced chondrocyte apoptosis and the potential molecular mechanisms. Chondrocytes were isolated from the joints of newborn Sprague-Dawley rats. The MTT assay and LDH cell death assay were used to determine the cell viability and chondrocyte apoptosis was detected by Annexin-V/PI staining and nucleosomal degradation. The contents of phosphorylated-PI3K (p-PI3k), phosphorylated-Akt (p-Akt), Bcl-2, Bax, and cytochrome c were detected by Western blotting. A quantitative colorimetric assay was used to detect the caspase-3 activity. Our results showed that pretreatment with shikonin (4 μM) inhibited cytotoxicity and apoptosis induced by IL-1β (10 ng/ml) in chondrocytes. Shikonin pretreatment also decreased the activity of IL-1β that decreased Bcl-2 expression and levels of p-PI3K and p-Akt, and increased Bax expression, cytochrome c release, and caspase-3 activation. It also reversed the activity of IL-1β that promoted the synthesis of matrix metalloproteinase-13 and inhibited the expression of tissue inhibitor of metalloproteinase-1 expression, with the net effect of suppressing extracellular matrix degradation. These data suggested that shikonin may protect chondrocytes from apoptosis induced by IL-1β through the PI3K/Akt signaling pathway, by deactivating caspase-3.
authors.affiliation: Department of Orthopedics, Qilu Hospital, Shandong University Jinan 250000, People's Republic of China ; Department of Orthopedics, Yantaishan Hospital Yantai 264000, People's Republic of China.
authors.forename: Leisheng
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Joint Surgery, Yantai Yuhuangding Hospital Yantai 264000, People's Republic of China.
authors.forename: Pengzhou
authors.initials: P
authors.lastname: Gai
authors.affiliation: Department of Orthopedics, Yantai Economic and Technology Development Area Hospital Yantai 264006, People's Republic of China.
authors.forename: Renguo
authors.initials: R
authors.lastname: Xu
authors.affiliation: Department of Orthopedics, Qilu Hospital, Shandong University Jinan 250000, People's Republic of China.
authors.forename: Yanpin
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Orthopedics, Yantaishan Hospital Yantai 264000, People's Republic of China.
authors.forename: Shiqiao
authors.initials: S
authors.lastname: Lv
authors.affiliation: Department of Orthopedics, Yantaishan Hospital Yantai 264000, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Yantaishan Hospital Yantai 264000, People's Republic of China.
authors.forename: Shaoxian
authors.initials: S
authors.lastname: Liu
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D008297:Male; D009285:Naphthoquinones / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D009285:Naphthoquinones; C016101:shikonin; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt
keywords: IL-β1; PI3K/Akt signaling; Shikonin; apoptosis; chondrocytes; osteoarthritis