Department of Dental Anesthesiology and Special Care Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8525, Japan.
Department of Dental Anesthesiology, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8525, Japan.
Arch Oral Biol. 2019 Feb;98:38-46. doi: 10.1016/j.archoralbio.2018.11.001. Epub 2018 Nov 2.
The aim of this study was to determine the effects of prolonged hyperoxia on salivary glands and salivary secretion in mice.
Male C57BL/6 J mice were kept in a 75% oxygen chamber (hyperoxia group) or a 21% oxygen chamber for 5 days. We measured the secretion volume, protein concentration, and amylase activity of saliva after the injection of pilocarpine. In addition, we evaluated the histological changes induced in the submandibular glands using hematoxylin and eosin and Alcian blue staining and assessed apoptotic changes using the TdT-mediated dUTP nick end labeling (TUNEL) assay. We also compared the submandibular gland expression levels of heme oxygenase-1 (HO-1), superoxide dismutase (SOD)-1, and SOD-2 using the real-time polymerase chain reaction.
In the hyperoxia group, salivary secretion was significantly inhibited at 5 and 10 min after the injection of pilocarpine, and the total salivary secretion volume was significantly decreased. The salivary protein concentration and amylase activity were also significantly higher in the hyperoxia group. In the histological examinations, enlargement of the mucous acini and the accumulation of mucins were observed in the submandibular region in the hyperoxia group, and the number of TUNEL-positive cells was also significantly increased in the hyperoxia group. Moreover, the expression levels of HO-1, SOD-1, and SOD-2 were significantly higher in the hyperoxia group.
Our results suggest that hyperoxia reduces salivary secretion, and oxidative stress reactions might be involved in this.
本研究旨在确定长时间高氧对小鼠唾液腺和唾液分泌的影响。
雄性 C57BL/6J 小鼠被置于 75%氧气室（高氧组）或 21%氧气室中 5 天。我们在注射毛果芸香碱后测量唾液的分泌量、蛋白浓度和淀粉酶活性。此外，我们使用苏木精和伊红以及阿尔辛蓝染色评估下颌下腺的组织学变化，并使用末端转移酶介导的 dUTP 缺口末端标记（TUNEL）测定法评估细胞凋亡变化。我们还通过实时聚合酶链反应比较了下颌下腺血红素加氧酶-1（HO-1）、超氧化物歧化酶（SOD）-1 和 SOD-2 的表达水平。
在高氧组中，注射毛果芸香碱后 5 分钟和 10 分钟时唾液分泌明显受到抑制，总唾液分泌量明显减少。高氧组的唾液蛋白浓度和淀粉酶活性也明显升高。在组织学检查中，高氧组下颌下区的黏液腺增大且黏蛋白堆积，TUNEL 阳性细胞的数量也明显增加。此外，高氧组 HO-1、SOD-1 和 SOD-2 的表达水平明显升高。
我们的结果表明，高氧会减少唾液分泌，氧化应激反应可能参与其中。
