Author(s)

Toru Ichiseki, Ayumi Kaneuji, Yoshimichi Ueda, Seiji Kaneko, Syusuke Ueda, Tadami Matsumoto

Department of Orthopaedic Surgery, Kanazawa Medical University, Ishikawa, Japan.
Department of Pathophysiological and Experimental Pathology, Kanazawa Medical University, Ishikawa, Japan.

Using a rabbit model, we examined N epsilon-(hexanoyl) lysine (HEL) levels in bone and urine to detect when peroxidative reaction first occurs after steroid administration. Japanese white rabbits weighing about 3.5 kg each were injected with a single intramuscular dose of methylprednisolone 40 mg/kg and divided into groups consisting of 10 rabbits each, which were killed after 1, 3, 5 and 14 days (groups A, B, C and D respectively). As a control, 10 untreated rabbits (group N) were also studied. The proximal femurs were examined histopathologically and immunohistochemically using monoclonal antibody HEL, which is a highly specific antibody against N epsilon-(hexanoyl) lysine, an early peroxidation marker. In addition, urinary levels of HEL were measured by enzyme-linked immunosorbent assay in group N, A, B and C. Osteonecrosis was detected only in group D (90%). Increase of positive reaction of HEL in the bone was observed in group A and D. HEL expression in group D was judged to be a secondary reaction resulting from the development of osteonecrosis. Urinary level of HEL showed a significant increase in only group A (P < 0.001). The present findings suggest that peroxidation in bone occurred within 24 hours after steroid administration in a rabbit model and that it is possible to noninvasively grasp the timing of this peroxidative reaction by measuring the urinary level of HEL.

Steroid; Osteonecrosis; Oxidative Stress; Hexanoyl Lysine

Ichiseki, T. , Kaneuji, A. , Ueda, Y. , Kaneko, S. , Ueda, S. and Matsumoto, T. (2012) The initial phase of oxidative stress in a steroid-induced osteonecrosis rabbit model. Advances in Bioscience and Biotechnology, 3, 978-982. doi: 10.4236/abb.2012.327120.