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Ofloxacin induces apoptosis in microencapsulated juvenile rabbit chondrocytes by caspase-8-dependent mitochondrial pathway

Journal Article · · Toxicology and Applied Pharmacology
 [1];  [2];  [3]; ; ;  [1]
  1. National Beijing Center for Drug Safety Evaluation and Research, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100850 (China)
  2. College of Vocational Technology, Inner Mongolia Agricultural University, Baotou 014100 (China)
  3. Tissue Engineering Research Center, Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Beijing 100850 (China)
Quinolones (QNs)-induced arthropathy is an important toxic effect in immature animals leading to restriction of their therapeutic use in pediatrics. However, the exact mechanism still remains unclear. Recently, we have demonstrated that ofloxacin, a typical QN, induces apoptosis of alginate microencapsulated juvenile rabbit joint chondrocytes by disturbing the {beta}{sub 1} integrin functions and inactivating the ERK/MAPK signaling pathway. In this study, we extend our initial observations to further elucidate the mechanism(s) of ofloxacin-induced apoptosis by utilizing specific caspase inhibitors. Pretreatment with both caspase-9-specific inhibitor zLEHD-fmk and caspase-8 inhibitor zIETD-fmk attenuated ofloxacin-induced apoptosis and activation of caspase-3 of chondrocyte in a concentration-dependent manner, as determined by fluorescent dye staining, enzyme activity assay and immunoblotting. Furthermore, the activation of caspase-9, -8 and -3 stimulated by ofloxacin was significantly inhibited in the presence of zIETD-fmk while pretreatment with zLEHD-fmk only blocked the activation of caspase-9 and -3. Ofloxacin also stimulated a concentration-dependent translocation of cytochrome c from mitochondria into the cytosol and a decrease of mitochondrial transmembrane potential, which was completely inhibited by zIETD-fmk. In addition, ofloxacin was found to increase the level of Bax, tBid, p53 in a concentration- and time-dependent manner. Taken together, The current results indicate that the caspase-8-dependent mitochondrial pathway is primarily involved in the ofloxacin-induced apoptosis of microencapsulated juvenile rabbit joint chondrocytes.
OSTI ID:
21077892
Journal Information:
Toxicology and Applied Pharmacology, Journal Name: Toxicology and Applied Pharmacology Journal Issue: 2 Vol. 226; ISSN TXAPA9; ISSN 0041-008X
Country of Publication:
United States
Language:
English