Hydrogen peroxide induces apoptosis of osteocytes: involvement of calcium ion and caspase activity.

We hypothesized that reactive oxygen species play an important role in avascular/ischemic osteonecrosis. When isolated chick osteocytes were cultured with hydrogen peroxide, annexin V binding, which is the earliest marker of apoptosis, increased in a dose-dependent fashion. Hydrogen peroxide also induced the activation of caspase-3 and increase in cytosolic Ca2+. Treatment with BAPTA/AM (cheletor of cytosolic Ca2+) and Ac-DEVD-cho (caspase inhibitor) attenuated hydrogen peroxide-induced apoptosis. These data demonstrated the signal transduction pathways that participate in this hydrogen peroxide-induced cell damage.