Yamamoto Hiroki, Saito Masazumi, Goto Tsuyoshi, Ueshima Keiichiro, Ishida Masashi, Hayashi Shigeki, Ikoma Kazuya, Mazda Osam, Kubo Toshikazu
Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
Med Mol Morphol. 2019 Sep;52(3):173-180. doi: 10.1007/s00795-018-00215-0. Epub 2019 Jan 31.
Glucocorticoids and hypoxia is considered to promote osteocyte apoptosis and necrosis, which are observed in glucocorticoid-associated osteonecrosis and osteoporosis. Heme oxygenase-1 (HO-1) induced by hemin is reported to have cytoprotective effects in ischemic diseases. The objective of this study was to evaluate the effect of HO-1 on osteocyte death caused by glucocorticoids and hypoxia. We confirmed that hemin induced HO-1 expression in MLO-Y4 mouse osteocytes. MLO-Y4 was cultured with dexamethasone (Dex) under hypoxia (DH group). Furthermore, these cells were cultured with hemin (DH-h group) or hemin and zinc protoporphyrin IX (an HO-1 inhibitor) (DH-h-PP group). The rates of apoptosis and necrosis of these groups were analyzed by flow cytometry and compared with cells cultured under normal condition. Both apoptosis and necrosis increased in the DH group. Hemin administration significantly reduced cell death caused by glucocorticoids and hypoxia in the DH-h group, and its effect was attenuated by the HO-1 inhibitor in DH-h-PP group. Capase-3 activity significantly decreased in the DH-h group. This implied that the cell death inhibition effect due to hemin is mediated by HO-1 and caspase-3. HO-1 induction may be useful in the treatment of glucocorticoid-associated osteonecrosis and osteoporosis.
糖皮质激素和缺氧被认为会促进骨细胞凋亡和坏死,这在糖皮质激素相关的骨坏死和骨质疏松症中可见。据报道,血红素诱导的血红素加氧酶-1(HO-1)在缺血性疾病中具有细胞保护作用。本研究的目的是评估HO-1对糖皮质激素和缺氧引起的骨细胞死亡的影响。我们证实血红素可诱导MLO-Y4小鼠骨细胞中HO-1的表达。将MLO-Y4细胞在缺氧条件下与地塞米松(Dex)一起培养(DH组)。此外,将这些细胞与血红素(DH-h组)或血红素和原卟啉锌IX(一种HO-1抑制剂)一起培养(DH-h-PP组)。通过流式细胞术分析这些组的凋亡和坏死率,并与在正常条件下培养的细胞进行比较。DH组的凋亡和坏死均增加。在DH-h组中,给予血红素可显著降低由糖皮质激素和缺氧引起的细胞死亡,而在DH-h-PP组中,HO-1抑制剂减弱了其作用。DH-h组中Caspase-3活性显著降低。这表明血红素引起的细胞死亡抑制作用是由HO-1和Caspase-3介导的。诱导HO-1可能对治疗糖皮质激素相关的骨坏死和骨质疏松症有用。