丙戊酸通过调控S100B蛋白对癫痫幼鼠认知功能、行为学及脑细胞凋亡的影响

Effects of valproic acid on cognitive function,ethology and brain cell apoptosis in epileptic juvenile rats by regulating S100B protein

目的 探究丙戊酸通过调控S100B蛋白对癫痫幼鼠认知功能、行为学及脑细胞凋亡的影响。方法 选取50只SPF级SD雄性幼鼠,随机分为正常(N)组、模型(M)组、丙戊酸(V)组、S100B蛋白抑制剂(P)组、丙戊酸联合S100B蛋白抑制剂(O)组,每组10只,对M组、V组、P组、O组用氯化锂加匹罗卡品建立癫痫模型,建模成功后,对V组腹腔注射20 mg/kg的丙戊酸,对P组腹腔注射5 mg/kg S100B抑制剂Pentamidine,对O组腹腔注射20 mg/kg丙戊酸和5 mg/kg Pentamidine, N组、M组同期腹腔注射同体积生理盐水,水迷宫法检测认知功能,旷场实验检测运动行为学,HE法检测脑组织病理形态,TUNEL法检测脑细胞凋亡,免疫组化法检测S100B蛋白表达。结果 与N组比较,M组、V组、P组逃避潜伏期、脑细胞凋亡率、脑组织S100B蛋白表达升高(P<0.05),穿越平台次数、平台象限停留时间、运动总距离、中央区运动距离、直立次数降低(P<0.05);与M组比较,V组、P组、O组逃避潜伏期、脑细胞凋亡率、脑组织S100B蛋白表达降低(P<0.05),穿越平台次数、平台象限停留时间、运动总距离、中央区运动距离、直立次数升高(P<0.05);且O组逃避潜伏期、脑细胞凋亡率、脑组织S100B蛋白表达低于P组(P<0.05),穿越平台次数、平台象限停留时间、运动总距离、中央区运动距离、直立次数高于P组(P<0.05)。N组脑组织结构正常,神经元细胞排列规整紧密,核仁正常清晰,胞浆及胞核清亮;M组脑组织结构受损,神经元细胞排列紊乱,可见明显变性坏死损伤,神经元明显丢失,胞核皱缩,胞浆出现透明空泡化。与M组比较,V组、P组、O组脑组织形态有所改善,神经元未见明显丢失。结论 丙戊酸可显著改善癫痫幼鼠认知功能、行为学,抑制脑细胞凋亡,其机制可能与抑制S100B蛋白有关。

Objective To explore the effects of valproic acid on cognitive function, ethology, and brain cell apoptosis in epileptic juvenile rats by regulating S100B protein. Methods A total of 50 SPF-grade SD male rats were randomly divided into normal(N) group, model(M) group, valproic acid(V) group, S100B protein inhibitor(P) group and valproic acid combined with S100B protein inhibitor(O) group, with 10 rats in each group. The epilepsy model was established in M, V, P and O groups with lithium chloride plus pilocarpine. After successful modeling, 20 mg/kg valproic acid was intraperitoneally injected into group V;5 mg/kg S100B inhibitor Pentamidine was intraperitoneally injected into group P, and 20 mg/kg valproic acid combined with 5 mg/kg Pentamidine was intraperitoneally injected into group O. The same volumes of normal saline were injected into groups N and M at the same time. Cognitive function was detected by water maze method. Open field test was used to detect movement behavior;HE method was used to detect pathological morphology of brain tissue;TUNEL method was used to detect brain cell apoptosis, and immunohistochemical method was used to detect S100B protein expression. Results Compared with group N, groups M,V,P showed significant increases in escape latencies, apoptotic rates of brain cells, and expressions of S100B protein(P<0.05), and decreases in platform crossing numbers, time spent in the target quadrant, total distances moved in the open field, distances moved in the central area, and numbers of rearing behaviors(P<0.05). Compared with group M, groups V, P, and O showed significant decreases in escape latencies, apoptotic rates of brain cells, and expressions of S100B protein(P<0.05), and increases in platform crossing numbers, time spent in the target quadrant, total distances moved in the open field, distances moved in the central area, and numbers of rearing behaviors(P<0.05). Group O showed decreased escape latency, apoptotic rate of brain cells, and expression of S100B protein, and increased platform crossing number, time spent in the target quadrant, total distance moved in the open field, distance moved in the central area, and number of rearing behaviors than group P(P<0.05). The brain tissue structure of group N was normal, with orderly and compact arrangement of neuronal cells, clear and normal nucleoli, and bright cytoplasm and nuclei. In contrast, the brain tissue structure of group M was disrupted, with disordered arrangement of neuronal cells, obvious degenerative necrotic damage, significant loss of neurons, nuclear shrinkage, and transparent vacuolization of cytoplasm. Compared to group M, the brain tissue morphology of groups V, P, and O improved, and no significant loss of neurons was observed. Conclusion Valproic acid can significantly improve the cognitive function, behavior and inhibit the apoptosis of brain cells in epileptic juvenile rats, and the mechanism may be related to the inhibition of S100B protein.