Li Bo, He Yue, Xu Liang, Hu Qin, Tang Junjia, Chen Yujie, Tang Jiping, Feng Hua, Zhang John H
Department of Basic Sciences, Division of Physiology, Loma Linda University School of Medicine, Loma Linda, CA.
Department of Neurosurgery, Jinan General Military Hospital, Jinan, People's Republic of China.
Crit Care Med. 2015 Aug;43(8):e304-e311. doi: 10.1097/CCM.0000000000001096.
Progranulin has been reported to have neuroprotective actions in cultured neurons. This study investigated the effect of recombinant rat progranulin on early brain injury after subarachnoid hemorrhage.
Controlled in vivo laboratory study.
Animal research laboratory.
Two hundred thirty adult male Sprague-Dawley rats weighing 280-320 g.
Subarachnoid hemorrhage was induced in rats by endovascular perforation. Rat recombinant progranulin (1 and 3 ng) was administrated intracerebroventricularly at 1.5 hours after subarachnoid hemorrhage. Progranulin small interfering RNA was administrated by intracerebroventricularly at 1 day before subarachnoid hemorrhage induction. Subarachnoid hemorrhage grade, neurologic score, and brain water content were measured at 24 and 72 hours after subarachnoid hemorrhage. Neural apoptosis was evaluated by double immunofluorescence staining using terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick-end labeling and neuronal nuclei. For mechanistic study, the expression of progranulin, phosphorylated Akt, Akt, p-Erk, Erk, Bcl-2, and cleaved caspase-3 were analyzed by Western blot at 24 hours after subarachnoid hemorrhage. siRNA for sortilin 1 (a progranulin receptor) was used to intervene the downstream pathway.
The expression of progranulin decreased and reached the lowest point at 24 hours after subarachnoid hemorrhage. Administration of rat recombinant progranulin decreased brain water content and improved neurologic functions at both 24 and 72 hours after subarachnoid hemorrhage, while knockdown of endogenous progranulin aggravated neurologic deficits after subarachnoid hemorrhage. Rat recombinant progranulin treatment reduced neuronal apoptosis, while progranulin deficiency promoted neuronal apoptosis at 24 hours after subarachnoid hemorrhage. Rat recombinant progranulin promoted Akt activation, increased Bcl-2 level, but reduced caspase-3 level. Knockdown of progranulin binding factor sortilin 1 abolished the beneficial effects of rat recombinant progranulin at 24 hours after subarachnoid hemorrhage.
Rat recombinant progranulin alleviated neuronal death via sortilin 1-mediated and Akt-related antiapoptosis pathway. Rat recombinant progranulin may have potentials to ameliorate early brain injury for subarachnoid hemorrhage patients.
据报道，颗粒蛋白前体在培养的神经元中具有神经保护作用。本研究调查了重组大鼠颗粒蛋白前体对蛛网膜下腔出血后早期脑损伤的影响。
体内对照实验室研究。
动物研究实验室。
230只体重280 - 320克的成年雄性Sprague-Dawley大鼠。
通过血管内穿刺诱导大鼠蛛网膜下腔出血。在蛛网膜下腔出血后1.5小时经脑室内给予大鼠重组颗粒蛋白前体（1和3纳克）。在诱导蛛网膜下腔出血前1天经脑室内给予颗粒蛋白前体小干扰RNA。在蛛网膜下腔出血后24小时和72小时测量蛛网膜下腔出血分级、神经功能评分和脑含水量。通过使用末端脱氧核苷酸转移酶介导的尿苷5'-三磷酸生物素缺口末端标记和神经元细胞核进行双重免疫荧光染色评估神经细胞凋亡。为进行机制研究，在蛛网膜下腔出血后24小时通过蛋白质免疫印迹法分析颗粒蛋白前体、磷酸化Akt、Akt、p-Erk、Erk、Bcl-2和裂解的半胱天冬酶-3的表达。使用sortilin 1（一种颗粒蛋白前体受体）的小干扰RNA干预下游途径。
颗粒蛋白前体的表达在蛛网膜下腔出血后24小时降低并达到最低点。给予大鼠重组颗粒蛋白前体可降低蛛网膜下腔出血后24小时和72小时的脑含水量并改善神经功能，而敲低内源性颗粒蛋白前体则加重蛛网膜下腔出血后的神经功能缺损。大鼠重组颗粒蛋白前体治疗减少神经细胞凋亡，而颗粒蛋白前体缺乏则在蛛网膜下腔出血后24小时促进神经细胞凋亡。大鼠重组颗粒蛋白前体促进Akt激活，增加Bcl-2水平，但降低半胱天冬酶-3水平。敲低颗粒蛋白前体结合因子sortilin 1消除了大鼠重组颗粒蛋白前体在蛛网膜下腔出血后2小时的有益作用。
大鼠重组颗粒蛋白前体通过sortilin 1介导的和Akt相关的抗凋亡途径减轻神经细胞死亡。大鼠重组颗粒蛋白前体可能具有改善蛛网膜下腔出血患者早期脑损伤的潜力。
