Abstract
Bach 1 is a transcription factor that negatively regulates the transcription of heme oxygenase‐1 (HO‐1), a stress‐responding protein. In this study, we investigated the reaction to oxidative stress in the meniscus of Bach 1 deficient mice, and the suppression of meniscal degeneration by the induction of HO‐1. We carried out a comparative study between Bach 1 deficient mice and wild type mice, in which the oxidative stress reaction and age‐related changes were investigated using the menisci of 6‐, 12‐, and 24‐week‐old mice. The degrees of meniscal degeneration and expression of HO‐1 were evaluated using the menisci cultured under oxidative stress with cadmium chloride or interleukin‐1 β. The age‐related changes in the meniscus were histologically examined. The expression of HO‐1 was higher, and the degrees of histological degeneration were lower in the Bach 1 deficient mice than in wild type mice (HO‐1 mRNA expression: In both the Cd group and the IL group, two–fourfold higher in the meniscus). The age‐related changes were lower in the Bach 1 deficient mice than in wild type mice. In 24‐week‐old mice, a moderate decrease in the cell density and proteoglycan content was observed in wild type mice compared with Bach 1 deficient mice. In the menisci of Bach 1 deficient mice, the anti‐oxidative stress activity was considered to be increased by abrogating the suppression of HO‐1 expression, resulting in a reduction of histological degeneration. This finding showed a potential new strategy for the prevention and treatment of meniscal degeneration. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:894–898, 2008