Levodopa attenuates cellular apoptosis in steroid-associated necrosis of the femoral head

Xi, Hongbo; Tao, Weijian; Jian, Zhengguang; Sun, Xuefeng; Gong, Xiaohong; Huang, Lixin; Dong, Tianhua

cell disease (n=5), and used TUNEL staining to detect the apoptotic cells. The results revealed that SANFH induced the apoptosis of a large number of bone cells, whereas patients with alcoholism-induced NFH exhibited less apoptotic cells, and no apoptotic cells were detected in the cases of NFH induced by the remaining causes. Therefore, it was concluded that SANFH was induced by the apoptosis of bone cells; however, this study was unable to prove the existence of apoptosis inside the necrotic bone cells of femoral head. Eberhardt et al (14) discovered that large doses of hormones were able to cause changes in cellular viabilities, with apoptosis demonstrated to be the primary change of SANFH. When bone cellular apoptosis was widespread, although blood vessels had no significant change, bone necrosis had already occurred. Calder et al (15) performed an immunohistochemical study of specimens from patients with non-traumatic osteonecrosis, and found that the nitric oxide synthase content was increased, which was considered to be due to the hormone's direct cytotoxic effects, leading to increased nitric oxide and mediating the occurrence of apoptosis. It was suggested that the apoptosis of bone cells has an important role in the pathogenesis of femoral head necrosis. In addition, it was shown that glucocorticoids are able to affect the proliferation and differentiation of bone cells, thus affecting the reconstruction and resorption of bones and decreasing the bone conversion rate, which further leads to osteoporosis, and the deposit of apoptotic bone cells (16) . Glucocorticoids were recognized as one of factors that may contribute cellular apoptosis (17) , thus promoting the apoptosis of osteoblasts and bone cells, leading to the reduction of bone cells. Furthermore, glucocorticoids may also affect the functions of osteoblasts, thus delaying bone formation and resulting in bone loss.