Bushen Zhuangjin decoction inhibits TM-induced chondrocyte apoptosis mediated by endoplasmic reticulum stress.
Chondrocyte apoptosis triggered by endoplasmic reticulum (ER) stress plays a vital role in the pathogenesis of osteoarthritis (OA). Bushen Zhuangjin decoction (BZD) has been widely used in the treatment of OA. However, the cellular and molecular mechanisms responsible for the inhibitory effects of BZD on chondrocyte apoptosis remain to be elucidated. In the present study, we investigated the effects of BZD on ER stress-induced chondrocyte apoptosis using a chondrocyte in vitro model of OA. Chondrocytes obtained from the articular cartilage of the knee joints of Sprague Dawley (SD) rats were detected by immunohistochemical staining for type Ⅱ collagen. The ER stress-mediated apoptosis of tunicamycin (TM)‑stimulated chondrocytes was detected using 4-phenylbutyric acid (4‑PBA). We found that 4‑PBA inhibited TM-induced chondrocyte apoptosis, which confirmed the successful induction of chondrocyte apoptosis. BZD enhanced the viability of the TM-stimulated chondrocytes in a dose- and time-dependent manner, as shown by MTT assay. The apoptotic rate and the loss of mitochondrial membrane potential (ΔΨm) of the TM-stimulated chondrocytes treated with BZD was markedly decreased compared with those of chondrocytes not treated with BZD, as shown by 4',6-diamidino-2-phenylindole (DAPI) staining, Annexin V-FITC binding assay and JC-1 assay. To further elucidate the mechanisms responsible for the inhibitory effects of BZD on TM‑induced chondrocyte apoptosis mediated by ER stress, the mRNA and protein expression levels of binding immunoglobulin protein (Bip), X‑box binding protein 1 (Xbp1), activating transcription factor 4 (Atf4), C/EBP‑homologous protein (Chop), caspase‑9, caspase-3, B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were measured by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. In the TM-stimulated chondrocytes treated with BZD, the mRNA and protein expression levels of Bip, Atf4, Chop, caspase-9, caspase-3 and Bax were significantly decreased, whereas the mRNA and protein expression levels of Xbp1 and Bcl-2 were significantly increased compared with the TM‑stimulated chondrocytes not treated with BZD. Additionally, all our findings demonstrated that there was no significant difference between the TM‑stimulated chondrocytes treated with BZD and those treated with 4‑PBA. Taken together, our results indicate that BZD inhibits TM‑induced chondrocyte apoptosis mediated by ER stress. Thus, BZD may be a potential therapeutic agent for use in the treatment of OA.
College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Pingdong
P
Lin
College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Xiaping
X
Weng
Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Fayuan
F
Liu
College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Yuhuan
Y
Ma
Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Houhuang
H
Chen
Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Xiang
X
Shao
Fujian Key Laboratory of Integrative Medicine on Geriatrics, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Wenwei
W
Zheng
Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Xianxiang
X
Liu
College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Hongzhi
H
Ye
Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China.
Xihai
X
Li
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D053453:Caspase 9 / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D015870:Gene Expression / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D010654:Phenylbutyrates / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D000071701:Regulatory Factor X Transcription Factors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051742:Transcription Factor CHOP / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology*; D000071717:X-Box Binding Protein 1; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP
D053148:Caspase 3; D053453:Caspase 9; D004268:DNA-Binding Proteins; D004365:Drugs, Chinese Herbal; D006360:Heat-Shock Proteins; D010654:Phenylbutyrates; D019253:Proto-Oncogene Proteins c-bcl-2; D000071701:Regulatory Factor X Transcription Factors; D051742:Transcription Factor CHOP; D014157:Transcription Factors; D014415:Tunicamycin; D000071717:X-Box Binding Protein 1; D051028:bcl-2-Associated X Protein; C494828:Bax protein, rat; C497251:Ddit3 protein, rat; C051684:GRP78 protein, rat; D000091342:Endoplasmic Reticulum Chaperone BiP; C000605545:Xbp1 protein, rat; C000610522:bushen zhuangjin; C075773:4-phenylbutyric acid