外源性H_2S对血管性痴呆大鼠海马MDA、SOD、Cyt C表达的影响

Effect of Exogenous H2S on Learning, Memory, MDA, SOD and Cyt C Expression in Brain Tissue of Rats with Vascular Dementia

目的:探讨外源性硫化氢(H_2S)对血管性痴呆大鼠(VaD)学习记忆能力、脑组织中丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性及神经元细胞色素C(Cyt C)表达的影响。方法:60只成年健康雄性SD大鼠随机分为假手术组(Sham)、模型组(VaD)、阳性对照组(Nimodipine)、NaSH低剂量组(Low-NaSH)及NaSH高剂量组(High-NaSH),除假手术组(仅分离双侧颈总动脉但不结扎)外,其余4组大鼠采用改良二血管法复制大鼠VaD模型,造模后阳性对照组给予尼莫地平10 mg/(kg·d)灌胃给药,NaSH低、高剂量组分别给予30μmoL/(kg·d)、100μmoL/(kg·d) NaSH灌胃给药,模型组及假手术组均给予等量生理盐水灌胃;给药30 d时,采用Morris水迷宫检测各组大鼠学习记忆能力,水迷宫测试结束后采用BCA蛋白定量法测定样本蛋白浓度记为C_(样本),结合标准曲线计算组织中MDA含量;用BCA法测定样本蛋白浓度C_(样本),计算组织中SOD活力单位;Western blot法检测海马胞浆Cyt C表达。结果:与Sham组比较,VaD组大鼠的学习记忆能力显著下降,神经元胞浆蛋白中Cyt C表达显著升高,脑组织中MDA含量显著增多、SOD活性显著升高(P<0.01);与VaD组大鼠比较,加NaSH处理后,大鼠学习记忆能力显著提高,神经元胞浆蛋白中Cyt C表达显著降低、脑组织中MDA含量及SOD活性均显著降低(P<0.01),与阳性对照组结果相近。结论:NaSH可改善VaD大鼠的学习记忆能力,其机制可能与NaSH降低大鼠海马的氧化应激水平、保护神经元细胞中线粒体功能有关。

Objective: To investigate the effect of exogenous hydrogen sulfide(H2 S) on the learning, memory, malondialdehyde(MDA) content, superoxide dismutase(SOD) activity of brain tissues and neuron cytochrome C(Cyt C) expression of rats with vascular dementia(VaD). Methods: Sixty healthy male SD rats were randomly divided into sham operation group(Sham), model group(VaD), positive control group(Nimodipine), NaSH low dose group(Low-NaSH) and NaSH high dose group(High-NaSH). The bilateral common carotid arteries were only isolated but not ligated in the sham group, and other rats were treated using the modified two-vessel method to generated VaD model. After the VaD model was established, the positive control group was intragastric administered with nimodipine 10 mg/(kg·d), and NaSH low-and high-dose groups were administered with 30 μmol/(kg·d) and 100 μmol/(kg·d) NaSH, respectively, while the model group and the sham group were given normal saline. After 30 day-treatment, the Morris water maze was used to detect rat learning and memory. The content of MDA and SOD activity in brain tissue were measured using their specific kits. T he expression level of Cyt C was measured by Western blot. Results: Compared with the Sham group, the learning and memory of the VaD group was significantly decreased, the expression of Cyt C in the cytoplasm of the neurons, MDA content and SOD activity in the brain tissue were significantly increased(P<0.01). Compared with VaD group, the learning and memory of NaSH group was significantly increased after NaSH treatment, and the expression of Cyt C in neuronal cytoplasm was significantly decreased, and the MDA content and SOD activity in brain tissue were significantly decreased(P<0.01). NaSH group exhibits similar phenotype to the positive control group. Conclusion: NaSH treatment can improve the learning and memory of VaD rats. The mechanism may be related to the decrease of oxidative stress in hippocampus and the protection of mitochondrial function in neurons.