Li Kai, Feng Zhanpeng, Ou Yichao, Zhou Mingfeng, Peng Junjie, Gong Haodong, Wu Guangsen, Liu Yawei, Qi Songtao
Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
First Clinical Medical College, Southern Medical University, Guangzhou 510515, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2019 Sep 30;39(9):1099-1106. doi: 10.12122/j.issn.1673-4254.2019.09.16.
To investigate the mechanism by which doublecortin promotes the recovery of cytoskeleton in arginine vasopressin (AVP) neurons in rats with electrical lesions of the pituitary stalk (PEL).
Thirty-two SD rats were randomized into PEL group with electrical lesions of the pituitary stalk through the floor of the skull base (=25) and sham operation group (=7), and the daily water consumption (DWC), daily urine volume (DUV) and urine specific gravity (USG) of the rats were recorded. Four rats on day 1 and 7 rats on each of days 3, 7 and 14 after PEL as well as the sham-operated rats were sacrificed for detection of the expressions of β-Tubulin (Tuj1), doublecortin and caspase- 3 in the AVP neurons of the supraoptic nucleus using immunofluorescence assay and Western blotting.
After PEL, the rats exhibited a typical triphasic pattern of diabetes insipidus, with the postoperative days 1-2 as the phase one, days 3-5 as the phase two, and days 6-14 as the phase three. Immunofluorescent results indicated the repair of the AVP neurons evidenced by significantly increased doublecortin expressions in the AVP neurons following PEL; similarly, the expression of Tuj1 also increased progressively after PEL, reaching the peak level on day 7 after PEL. The apoptotic rates of the AVP neurons exhibited a reverse pattern of variation, peaking on postoperative day 3 followed by progressive reduction till day 14. Western blotting showed that the expressions of c-Jun and p-c-Jun were up-regulated significantly on day 3 ( < 0.05) and 7 ( < 0.01) after PEL, while an upregulated p-JNK expression was detected only on day 3 ( < 0.05), as was consistent with the time-courses of neuronal recovery and apoptosis after PEL.
JNK/c-Jun pathway is activated after PEL to induce apoptosis of AVP neurons in the acute phase and to promote the repair of neuronal cytoskeleton by up-regulation of doublecortin and Tuj1 expressions.
探讨双皮质素促进垂体柄电损伤（PEL）大鼠精氨酸加压素（AVP）神经元细胞骨架恢复的机制。
将32只SD大鼠随机分为垂体柄电损伤组（通过颅底经皮电损伤垂体柄，n = 25）和假手术组（n = 7），记录大鼠每日饮水量（DWC）、每日尿量（DUV）和尿比重（USG）。PEL术后第1天取4只大鼠，术后第3、7和14天各取7只大鼠，并处死假手术大鼠，采用免疫荧光法和蛋白质印迹法检测视上核AVP神经元中β-微管蛋白（Tuj1）、双皮质素和半胱天冬酶-3的表达。
PEL术后，大鼠呈现典型的尿崩症三相模式，术后第1 - 2天为第一阶段，第3 - 5天为第二阶段，第6 - 14天为第三阶段。免疫荧光结果表明AVP神经元得到修复，表现为PEL后AVP神经元中双皮质素表达显著增加；同样，PEL后Tuj1表达也逐渐增加，在PEL后第7天达到峰值水平。AVP神经元的凋亡率呈现相反的变化模式，术后第3天达到峰值，随后逐渐降低直至第14天。蛋白质印迹显示，PEL后第3天（P < 0.05）和第7天（P < 0.01）c-Jun和p-c-Jun表达显著上调，而仅在第3天检测到p-JNK表达上调（P < 0.05），这与PEL后神经元恢复和凋亡的时间进程一致。
PEL后JNK/c-Jun通路被激活，在急性期诱导AVP神经元凋亡，并通过上调双皮质素和Tuj1表达促进神经元细胞骨架的修复。
