TNF/TNFR1 pathway and endoplasmic reticulum stress are involved in ofloxacin-induced apoptosis of juvenile canine chondrocytes

• Published in: Toxicology and applied pharmacology 2014-04, Vol.276 (2), p.121-128
• Main Authors: Zhang, Fu-Tao, Ding, Yi, Shah, Zahir, Xing, Dan, Gao, Yuan, Liu, Dong Ming, Ding, Ming-Xing
• Format: Article
• Language: English
• Subjects: Aging; Animals; Anti-Bacterial Agents - toxicity; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Apoptosis; Apoptosis - drug effects; Biological and medical sciences; Canine chondrocytes; Caspase 12 - analysis; Cells, Cultured; Chondrocytes - drug effects; Chondrocytes - pathology; Dogs; Dose-Response Relationship, Drug; Endoplasmic reticulum stress; Endoplasmic Reticulum Stress - physiology; Medical sciences; Ofloxacin; Ofloxacin - toxicity; Pharmacology. Drug treatments; Quinolones; Receptors, Tumor Necrosis Factor, Type I - genetics; Receptors, Tumor Necrosis Factor, Type I - physiology; RNA, Messenger - analysis; Signal Transduction - physiology; TNF/TNFR1 pathway; Toxicology; Tumor Necrosis Factor-alpha - genetics; Tumor Necrosis Factor-alpha - physiology
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2014.02.003

Quinolones cause obvious cartilaginous lesions in juvenile animals by chondrocyte apoptosis, which results in the restriction of their use in pediatric and adolescent patients. Studies showed that chondrocytes can be induced to produce TNFα, and the cisternae of the endoplasmic reticulum in quinolone-treated chondrocytes become dilated. We investigated whether TNF/TNFR1 pathway and endoplasmic reticulum stress (ERs) are involved in ofloxacin (a typical quinolone)-induced apoptosis of juvenile canine chondrocytes. Canine juvenile chondrocytes were treated with ofloxacin. Cell survival and apoptosis rates were determined with MTT method and flow cytometry, respectively. The gene expression levels of the related signaling molecules (TNFα, TNFR1, TRADD, FADD and caspase-8) in death receptor pathways and main apoptosis-related molecules (calpain, caspase-12, GADD153 and GRP78) in ERs were measured by qRT-PCR. The gene expression of TNFR1 was suppressed with its siRNA. The protein levels of TNFα, TNFR1 and caspase-12 were assayed using Western blotting. The survival rates decreased while apoptosis rates increased after the chondrocytes were treated with ofloxacin. The mRNA levels of the measured apoptosis-related molecules in death receptor pathways and ERs, and the protein levels of TNFα, TNFR1 and caspase-12 increased after the chondrocytes were exposed to ofloxacin. The downregulated mRNA expressions of TNFR1, Caspase-8 and TRADD, and the decreased apoptosis rates of the ofloxacin-treated chondrocytes occurred after TNFR1–siRNA interference. Ofloxacin-induced chondrocyte apoptosis in a time- and concentration-dependent fashion. TNF/TNFR1 pathway and ERs are involved in ofloxacin-induced apoptosis of juvenile canine chondrocytes in the early stage. •Chondrocyte apoptosis is induced by ofloxacin in a time- and concentration-dependent manners.•TNF/TNFR1 pathway is involved in ofloxacin-induced apoptosis of chondrocytes in the early stage.•Endoplasmic reticulum stress is involved in ofloxacin-induced apoptosis of chondrocytes in the early stage.