Peng Weifeng, Hu Zihan, Shen Yijun, Wang Xin
Department of Neurology, Shanghai Geriatric Medical Center, Shanghai, China.
Department of Neurology, Zhongshan Hospital Fudan University Xiamen Branch, Xiamen, China.
IBRO Neurosci Rep. 2024 Oct 11;17:329-336. doi: 10.1016/j.ibneur.2024.10.001. eCollection 2024 Dec.
This study aimed to investigate the enzyme activity of soluble epoxide hydrolase (sEH) and quantify its metabolic substrates, namely epoxygenated fatty acids (EpFAs), and products of sEH in the hippocampus after administering TPPU [1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl)urea], an inhibitor of sEH. Furthermore, it explored whether the extracellular signal-activated protein kinase 1/2 (ERK1/2) is involved in the anti-seizure effects of TPPU in the lithium chloride (LiCl)-pilocarpine induced post-status epilepticus (SE) rat model.
The rats were intraperitoneally (I.P.) injected with LiCl and pilocarpine to induce SE and then spontaneous recurrent seizures (SRS) were observed. Rats were randomly assigned into SRS + TPPU group (intragastrically administering 0.1 mg/kg/d TPPU), SRS + Vehicle group (administering the vehicle instead), and Control group. Enzyme-linked immunosorbent assay, Western-blot analysis, and ultra-high-performance liquid chromatography/mass spectrometry (LC/MS) were performed to measure the enzyme activity of sEH, the protein level of sEH and ERK1/2, and the concentration of TPPU and polyunsaturated fatty acids (PUFAs) metabolisms in the hippocampus.
The frequency of SRS events of Racine stage 3 or higher ranged from 0 to 19 per week in the SRS + Vehicle group, compared to 0-5 per week in the SRS + TPPU group. sEH enzyme activity and protein levels were significantly elevated in the SRS + Vehicle group compared to the Control group. After TPPU administration, the hippocampal TPPU concentration reached 10.94 ± 4.37 nmol/kg. sEH enzyme activity was significantly reduced in the LiCl-pilocarpine-induced post-SE rat model, although sEH protein levels did not decrease significantly. The regioisomers 8,9-, 11,12-, and 14,15-EETs, total EETs, the EETs/DHETs ratio, other EpFAs including 16(17)-EpDPA, and the 19(20)-EpDPA/19,20-DiHDPA ratio in the hippocampus were significantly increased. Additionally, the p-ERK1/2 to ERK1/2 ratio in the hippocampus was significantly elevated following TPPU administration.
This study demonstrates that inhibiting sEH with TPPU increases the levels of EETs, other EpFAs, and ERK1/2 expression in the hippocampus of a LiCl-pilocarpine-induced post-SE rat model. These findings suggest that the anti-seizure effect of TPPU may be mediated through the EETs-ERK1/2 pathway.
本研究旨在探讨在给予可溶性环氧化物水解酶（sEH）抑制剂TPPU [1-三氟甲氧基苯基-3-(1-丙酰基哌啶-4-基)脲]后，海马中sEH的酶活性，定量其代谢底物即环氧化脂肪酸（EpFAs）以及sEH的产物。此外，还探究了细胞外信号调节激酶1/2（ERK1/2）是否参与TPPU在氯化锂（LiCl）-匹罗卡品诱导的癫痫持续状态（SE）大鼠模型中的抗癫痫作用。
大鼠腹腔注射LiCl和匹罗卡品诱导SE，随后观察自发性复发性癫痫（SRS）。将大鼠随机分为SRS + TPPU组（灌胃给予0.1 mg/kg/d TPPU）、SRS + 赋形剂组（给予赋形剂替代）和对照组。采用酶联免疫吸附测定、蛋白质免疫印迹分析和超高效液相色谱/质谱联用（LC/MS）法，检测海马中sEH的酶活性、sEH和ERK1/2的蛋白水平以及TPPU和多不饱和脂肪酸（PUFAs）代谢产物的浓度。
SRS + 赋形剂组中拉辛3级或更高等级的SRS事件频率为每周0至19次，而SRS + TPPU组为每周0至5次。与对照组相比，SRS + 赋形剂组中sEH酶活性和蛋白水平显著升高。给予TPPU后，海马中TPPU浓度达到10.94 ± 4.37 nmol/kg。在LiCl-匹罗卡品诱导的SE后大鼠模型中，sEH酶活性显著降低，尽管sEH蛋白水平没有显著下降。海马中的区域异构体8,9-、11,12-和14,15-EETs、总EETs、EETs/DHETs比值、其他EpFAs包括16(17)-EpDPA以及19(20)-EpDPA/19,20-DiHDPA比值均显著增加。此外，给予TPPU后海马中p-ERK1/2与ERK1/2的比值显著升高。
本研究表明，在LiCl-匹罗卡品诱导的SE后大鼠模型中，用TPPU抑制sEH可增加海马中EETs、其他EpFAs的水平以及ERK1/2的表达。这些发现提示TPPU的抗癫痫作用可能通过EETs-ERK1/2途径介导。
