Objective: To study the effect of pranlukast (Pran) on neonatal rats with periventricular leukomalacia (PVL).
Methods: The rats, aged 3 days, were randomly divided into a sham-operation group, a PVL group, and a Pran group. A rat model of PVL was prepared by right common carotid artery ligation and postoperative hypoxia. The rats in the sham-operation group were given isolation of the right common carotid artery without ligation or hypoxic treatment. The rats in the Pran group were given intraperitoneal injection of Pran (0.1 mg/kg) once every 12 hours, for 3 consecutive days, and those in the sham-operation group and the PVL group were given intraperitoneal injection of an equal volume of normal saline. On day 14 after modeling, hematoxylin-eosin (HE) staining was used to observe the pathological changes of brain tissue; immunofluorescent staining was used to measure the expression of myelin basic protein (MBP) in brain tissue (n=8); Western blot was used to measure the expression of cyclic nucleotide phosphodiesterase (CNPase), MBP, and G protein-coupled receptor 17 (GPR17) (n=8). On day 21 after modeling, Morris water maze test was used to evaluate the learning and memory abilities of rats in each group (n=8).
Results: The results of HE staining showed that the PVL group had greater pathological changes of white matter than the sham-operation group, and compared with the PVL group, the Pran group had a significant improvement in such pathological changes. The results of immunofluorescence assay showed that the PVL group had a lower mean fluorescence intensity of MBP than the sham-operation group (P<0.05), and the Pran group had a higher mean fluorescence intensity of MBP than the PVL group (P<0.05). Western blot showed that compared with the sham-operation group, the PVL group had significantly lower relative expression of MBP and CNPase (P<0.05) and significantly higher relative expression of GPR17 (P<0.05), and compared with the PVL group, the Pran group had significantly higher relative expression of MBP and CNPase (P<0.05) and significantly lower relative expression of GPR17 (P<0.05). Morris water maze test showed that compared with the sham-operation group, the PVL group had a significant increase in escape latency and a significant reduction in the number of platform crossings, and compared with the PVL group, the Pran group had a significant reduction in escape latency and a significant increase in the number of platform crossings (P<0.05).
Conclusions: Pran can alleviate brain damage, promote myelination, and improve long-term learning and memory abilities in neonatal rats with PVL, possibly by reducing the expression of GPR17.
目的: 探讨普仑司特（Pran）对脑室周围白质软化（PVL）新生大鼠的作用。
方法: 将3日龄大鼠随机分为假手术（Sham）组、PVL组和Pran组。通过右侧颈总动脉结扎及术后缺氧建立PVL模型，Sham组大鼠仅游离右侧颈总动脉，不予结扎，也不进行缺氧处理。Pran组缺氧后经腹腔注射Pran（0.1 mg/kg），每12 h注射1次，连续注射3 d，Sham组和PVL组分别给予等量生理盐水腹腔注射。造模后14 d，通过苏木精-伊红染色法观察脑组织病理变化，免疫荧光染色法检测脑组织髓鞘碱性蛋白（MBP）表达（n=8），免疫印迹法测定环核苷酸磷酸二酯酶（CNPase）、MBP和G蛋白偶联受体17（GPR17）表达（n=8）。造模后21 d，应用Morris水迷宫实验评价各组大鼠的学习记忆能力（n=8）。
结果: HE染色结果表明：PVL组与Sham组比较脑白质出现明显病理性改变，Pran组病理变化较PVL组明显改善。免疫荧光结果显示：PVL组MBP平均荧光强度低于Sham组，Pran组MBP平均荧光强度高于PVL组（P < 0.05）。Western blot结果显示：PVL组MBP和CNPase蛋白相对表达均低于Sham组，GPR17蛋白相对表达高于Sham组（P < 0.05）；Pran组MBP和CNPase蛋白相对表达均高于PVL组，GPR17蛋白相对表达低于PVL组（P < 0.05）。Morris水迷宫实验结果显示：PVL组与Sham组比较，逃避潜伏期延长，穿越平台次数减少；Pran组与PVL组比较，逃避潜伏期缩短，穿越平台次数增加（P < 0.05）。
结论: Pran可减轻PVL新生大鼠的脑损伤，促进髓鞘形成，改善远期学习记忆能力。其作用机制可能与下调GPR17的表达有关。