Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea.
Neurotoxicology. 2019 Mar;71:132-137. doi: 10.1016/j.neuro.2019.01.001. Epub 2019 Jan 9.
Serine synthetic pathway plays an essential role in the development and function of the nervous system. This study investigated whether the serine synthetic pathway was affected by repeated volatile anesthetic exposure using C. elegans and its relationship with anesthesia-induced neurotoxicity.
Synchronized worms were divided into two groups: the control and isoflurane groups. Worms in the isoflurane group were exposed to isoflurane for 1 h at each larval stage. The chemotaxis index was evaluated when they reached the young adult-stage in both groups. Also, RNA was extracted from the young adult-worms, and the expressions of C31C9.2, F26H9.5, and Y62E10 A.13 were evaluated using real-time polymerase chain reaction in both groups. At the same time, the l-serine level was measured. After phosphoserine phosphatase inhibitor - glycerophosphorylcholine (GPC) - and l-serine were treated, the change of chemotaxis index was determined.
In young adult worms exposed to isoflurane, the genetic expressions of C31C9.2, F26H9.5, and Y62E10 A.13 were decreased, and a significant decrease was shown in Y62E10 A.13. The serine level in worms was also lower in the isoflurane group than in the control group (5.13 ± 1.44 vs. 7.65 ± 0.81 pM, n = 5 in each group, p = 0.009). Exposure to GPC reduced the chemotaxis index to a similar degree as repeated isoflurane exposure (52.9% in GPC group vs 58.7% in the isoflurane group). The chemotaxis index (61.1%) was not decreased by repeated isoflurane anesthesia in GPC-treated worms. In this condition, the l-serine level was low similarly in both groups (5.22 ± 1.19 vs. 4.90 ± 1.36 pM, n = 5 in each group, p = 0.702). When l-serine was supplied to C. elegans, the deteriorated chemotaxis index by isoflurane exposure recovered (78.1% in the control group vs. 75.5% in the isoflurane group, p = 0.465).
Serine synthetic pathway was negatively affected in C. elegans by repeated isoflurane exposure. Y62E10 A.13, which corresponds to phosphoserine phosphatase, was mostly influenced, followed by low l-serine level. Supplementation with l-serine could restore the chemotaxis index.
丝氨酸合成途径在神经系统的发育和功能中起着至关重要的作用。本研究使用秀丽隐杆线虫（C. elegans）探讨了丝氨酸合成途径是否会受到重复吸入麻醉剂的影响，以及这种影响与麻醉诱导的神经毒性之间的关系。
将同步化的线虫分为两组：对照组和异氟醚组。异氟醚组的线虫在每个幼虫阶段都要暴露于异氟醚中 1 小时。两组的线虫在达到成虫期时评估趋化性指数。同时，从成虫期的线虫中提取 RNA，并使用实时聚合酶链反应（PCR）评估两组中 C31C9.2、F26H9.5 和 Y62E10A.13 的表达。同时，测量 l-丝氨酸水平。用磷酸丝氨酸磷酸酶抑制剂 - 甘油磷酸胆碱（GPC）和 l-丝氨酸处理后，确定趋化性指数的变化。
在暴露于异氟醚的成虫期线虫中，C31C9.2、F26H9.5 和 Y62E10A.13 的基因表达下降，其中 Y62E10A.13 的下降最为显著。异氟醚组线虫的丝氨酸水平也低于对照组（5.13±1.44 对 7.65±0.81 pM，每组 5 个样本，p=0.009）。暴露于 GPC 可使趋化性指数降低至与重复异氟醚暴露相似的程度（GPC 组为 52.9%，异氟醚组为 58.7%）。在 GPC 处理的线虫中，重复异氟醚麻醉并未降低趋化性指数（GPC 组为 61.1%）。在这种情况下，两组的 l-丝氨酸水平相似较低（5.22±1.19 对 4.90±1.36 pM，每组 5 个样本，p=0.702）。当向 C. elegans 提供 l-丝氨酸时，异氟醚暴露引起的趋化性指数恶化得到恢复（对照组为 78.1%，异氟醚组为 75.5%，p=0.465）。
重复异氟醚暴露会使秀丽隐杆线虫的丝氨酸合成途径受到负面影响。磷酸丝氨酸磷酸酶对应的 Y62E10A.13 受到的影响最大，其次是 l-丝氨酸水平降低。补充 l-丝氨酸可以恢复趋化性指数。
