Motohira Hitoshi, Hayashi Joichiro, Tatsumi Junichi, Tajima Masamichi, Sakagami Hiroshi, Shin Kitetsu
Division of Periodontology, Department of Oral Biology and Tissue Engineering, Meikai University School of Dentistry, Saitama, Japan.
J Periodontol. 2007 Sep;78(9):1803-9. doi: 10.1902/jop.2007.060519.
Oxygen deficiency caused by occlusal trauma and smoking may be associated with bone resorption in periodontitis. In the present study, the effects of hypoxia and reoxygenation on the production of bone-resorbing factors by cultured human periodontal ligament (PDL) cells were examined.
Human PDL cells were cultured in 1% O(2) (hypoxia), 20% O(2) (normal oxygen tension [normoxia]), or an oxygen concentration that went from 1% to 20% (reoxygenation). The concentrations of bone-resorbing factors, i.e., vascular endothelial growth factor (VEGF), interleukin (IL)-6 and -1beta, tumor necrosis factor-alpha (TNF-alpha), and prostaglandin E(2) (PGE(2)), in the cell culture supernatants were determined by enzyme-linked immunosorbent assay. Expression of the corresponding mRNAs was detected by reverse transcription-polymerase chain reaction.
Significantly higher extracellular concentrations of VEGF and IL-6 were detected along with greater corresponding mRNA expression in the hypoxia group compared to the normoxia group. The protein production and mRNA expression of IL-1beta were observed only in the hypoxia group. Neither TNF-alpha nor PGE(2) was detectable in samples from either group, whereas cyclooxygenase-2 mRNA was detected. However, PGE(2) was detected after reoxygenation. Furthermore, VEGF and IL-6 and -1beta production also tended to increase in extracellular concentration and mRNA level after reoxygenation.
Hypoxia and reoxygenation may stimulate the PDL to produce VEGF, IL-6 and -1beta, and PGE2, which could result in the resorption of alveolar bone in periodontitis.
咬合创伤和吸烟导致的缺氧可能与牙周炎中的骨吸收有关。在本研究中，检测了缺氧和复氧对培养的人牙周膜（PDL）细胞产生骨吸收因子的影响。
将人PDL细胞在1%氧气（缺氧）、20%氧气（正常氧张力[常氧]）或从1%到20%的氧浓度（复氧）条件下培养。通过酶联免疫吸附测定法测定细胞培养上清液中骨吸收因子，即血管内皮生长因子（VEGF）、白细胞介素（IL）-6和-1β、肿瘤坏死因子-α（TNF-α）和前列腺素E2（PGE2）的浓度。通过逆转录-聚合酶链反应检测相应mRNA的表达。
与常氧组相比，缺氧组检测到细胞外VEGF和IL-6浓度显著更高，且相应的mRNA表达也更高。仅在缺氧组观察到IL-1β的蛋白质产生和mRNA表达。两组样本中均未检测到TNF-α和PGE2，而检测到环氧化酶-2 mRNA。然而，复氧后检测到了PGE2。此外，复氧后VEGF、IL-6和-1β的细胞外浓度和mRNA水平也有增加的趋势。
缺氧和复氧可能刺激PDL产生VEGF、IL-6、-1β和PGE2，这可能导致牙周炎中牙槽骨的吸收。
