CAJ | 학술논문

目的：探讨γ-分泌酶抑制剂（N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, DAPT）对常压高浓度氧暴露致新生小鼠脑白质损伤中的作用。方法将新生3 d小鼠持续80%高氧暴露48 h，建立新生鼠未成熟高氧脑损伤模型，并于高氧暴露前1 h通过腹腔注射DAPT（10 mg/kg），将小鼠分为空气对照组（C），空气+DAPT组（C+DAPT），高氧组（H），高氧+DAPT组（H+DAPT）。检测第3，5、12及28天各组小鼠的脑质量、体质量；模型制作后48 h RT-PCR检测小鼠脑组织NICD mRNA（Notch intracellular domain）的表达；第12天免疫组化检测NG2和MBP（myelin basic protein）表达；第28天Morris水迷宫评价各组小鼠学习记忆能力。结果与C组比较，H组小鼠随着日龄延长小鼠脑质量、体质量均明显下降（P<0.05）；与H组比较，给予DAPT预处理高氧暴露（H+DAPT组）后，小鼠脑质量、体质量显著增加（P<0.05）；RT-PCR提示高氧暴露后NICD mRNA表达上调，DAPT可逆转高氧所致脑组织中NICD上调；免疫荧光双标显示H组NG2细胞增多，MBP细胞减少；与H组比较，DAPT预处理后（H+DAPT组）NG2细胞明显减少，MBP细胞明显增多；Morris水迷宫H组与C组比较，逃避潜伏期和游动距离均延长（P<0.05），目标象限停留时间缩短（P<0.05），穿越虚拟平台次数减少（P<0.05）；而H+DAPT组与H组比较上述各项指标均明显好转。结论γ-分泌酶抑制剂（DAPT）可抑制高氧暴露所致脑内Notch信号水平的变化，减轻高氧诱导未成熟脑白质损伤，降低新生期高氧暴露对远期学习记忆能力损害。
목적：탐토γ-분비매억제제（N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, DAPT）대상압고농도양폭로치신생소서뇌백질손상중적작용。방법장신생3 d소서지속80%고양폭로48 h，건립신생서미성숙고양뇌손상모형，병우고양폭로전1 h통과복강주사DAPT（10 mg/kg），장소서분위공기대조조（C），공기+DAPT조（C+DAPT），고양조（H），고양+DAPT조（H+DAPT）。검측제3，5、12급28천각조소서적뇌질량、체질량；모형제작후48 h RT-PCR검측소서뇌조직NICD mRNA（Notch intracellular domain）적표체；제12천면역조화검측NG2화MBP（myelin basic protein）표체；제28천Morris수미궁평개각조소서학습기억능력。결과여C조비교，H조소서수착일령연장소서뇌질량、체질량균명현하강（P<0.05）；여H조비교，급여DAPT예처리고양폭로（H+DAPT조）후，소서뇌질량、체질량현저증가（P<0.05）；RT-PCR제시고양폭로후NICD mRNA표체상조，DAPT가역전고양소치뇌조직중NICD상조；면역형광쌍표현시H조NG2세포증다，MBP세포감소；여H조비교，DAPT예처리후（H+DAPT조）NG2세포명현감소，MBP세포명현증다；Morris수미궁H조여C조비교，도피잠복기화유동거리균연장（P<0.05），목표상한정류시간축단（P<0.05），천월허의평태차수감소（P<0.05）；이H+DAPT조여H조비교상술각항지표균명현호전。결론γ-분비매억제제（DAPT）가억제고양폭로소치뇌내Notch신호수평적변화，감경고양유도미성숙뇌백질손상，강저신생기고양폭로대원기학습기억능력손해。
Objective To investigate the effect ofγ-secretase inhibitor (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, DAPT) on hyperoxia-induced brain white matter injury in mice. Methods Three-day-old C57BL/10J mouse pups were divided into air control (C) group, control+DAPT (10 mg/kg, injected intraperitoneally) group, hyperoxia group (exposed to 80% oxygen for 48 h), and hyperoxia+DAPT group. The brain and body weights of the mice were measured at postnatal days 3, 5, 12, and 28. Real-time PCR was used to detect Notch intracellular domain (NICD) mRNA expression in the brain after modeling, and the expressions of NG2 and myelin basic protein (MBP) were detected by double-labeled immunofluorescence assay to verify the oligdendrocycle type at postnatal day 12. The mice in each group were bred until postnatal day 28 for Morris water maze test. Results The brain and body weights were significantly decreased in mice in hyperoxia group compared to the control mice, but increased significantly after DAPT treatment (P<0.05). Real-time PCR showed that a 48-hour hyperoxia exposure significantly increased NICD mRNA expression in the brain (P<0.05), which was decreased by co-treatment by DAPT (P<0.05). Hyperoxia also resulted in enhanced NG2 expression and lowered MBP expression in the brain (P<0.05). Compared with the control mice, the mice exposed to hyperoxia showed prolonged escape latency (P<0.05) and spent less time in the target quadrant with a lowered number of passing through the virtual platform (P<0.05). All these parameters were significantly improved by co-treatment with DAPT. Conclusion Specific inhibition of Notch signaling pathway activation in the brain by the γ-secretase inhibitor DAPT can ameliorate white matter injury and learning and memory impairment in newborn mice with hyperoxia exposure.