Objective: To observe the effect of moxibustion on proteins related with apoptosis of hippocampal neurons in rats with vascular dementia (VD), and to explore the possible mechanism of moxibustion on improving VD.
Methods: Thirty SD rats were selected from 100 rats (3 rats were excluded) and randomly divided into a normal group and a sham operation group, 15 rats in each group. The remaining 67 rats were treated with ischemia-reperfusion method at bilateral common carotid artery to establish VD model. The 45 rats with successful VD model were randomly divided into a model group, a moxibustion group and a medication group, 15 rats in each group. On the 7th day after successful modeling, the rats in the moxibustion group were treated with suspended moxibustion at "Guanyuan" (CV 4), "Mingmen" (GV 4) and "Dazhui" (GV 14), 15 min per acupoint, once a day; there was 1 d of rest after 6 d of moxibustion, and the treatment was given for 4 weeks. The rats in the medication group was treated with nimodipine tablets by gavage, 2 mg/kg per day, 3 times a day for 4 weeks. Before and after intervention, the Morris water maze test was used to detect the escape latency of rats in each group; after the intervention, the TUNEL method was used to detect the apoptosis rate of neurons in hippocampal CA1 area; the immunofluorescence double labeling method was used to detect the number of co-expression positive cells of B-cell lymphoma-2 (Bcl-2)/neuronal nuclear antigen (NeuN) and Bcl-2-associated X protein (Bax)/NeuN in hippocampal CA1 area; the immunofluorescence single labeling method was used to detect cytochrome C (cytC) and outer mitochondrial membrane receptor Tom20 (Tom20) in hippocampal CA1 area; the Western blot method was used to detect the p53 upregulated modulator of apoptosis (PUMA) in hippocampus.
Results: Before intervention, compared with the normal group and the sham operation group, the escape latency in the model group, the moxibustion group and the medication group was prolonged (P<0.01). After intervention, the escape latency in the moxibustion group and the medication group was shorter than that before intervention (P<0.01). Compared with the model group, the escape latency in the moxibustion group and the medication group was shortened (P<0.05); compared with the medication group, the escape latency in the moxibustion group was shortened (P<0.05). Compared with the normal group and the sham operation group, the apoptosis rate of neurons in hippocampal CA1 area was increased, the number of Bcl-2/NeuN co-expression positive cells was decreased, and the number of Bax/NeuN co-expression positive cells was increased in the model group (P<0.01); compared with the model group, the apoptosis rates of hippocampal CA1 neurons were decreased, the number of Bcl-2/NeuN co-expression positive cells was increased, and the number of Bax/NeuN co-expression positive cells was decreased in the moxibustion group and the medication group (P<0.01); compared with the medication group, the apoptosis rate of neurons in hippocampal CA1 area was decreased, the number of Bcl-2/NeuN co-expression positive cells was increased, and the number of Bax/NeuN co-expression positive cells was decreased in the moxibustion group (P<0.01, P<0.05). Compared with the normal group and the sham operation group, the expressions of cytC, Tom20 protein in hippocampal CA1 area and PUMA protein in hippocampal tissue in the model group were increased (P<0.01); compared with the model group, the expressions of cytC, Tom20 protein in hippocampal CA1 area and PUMA protein in hippocampal tissue in the moxibustion group and the medication group were decreased (P<0.01); compared with the medication group, the expressions of cytC, Tom20 protein in hippocampal CA1 area and PUMA protein in hippocampal tissue in the moxibustion group were decreased (P<0.05, P<0.01).
Conclusion: Moxibustion could improve the cognitive function of VD rats, which may be related to reducing the expression of Bax, cytC, Tom20 and PUMA protein in hippocampal CA1 area, promoting the release of Bcl-2 and inhibiting the apoptosis of hippocampal neurons.
目的：观察艾灸对血管性痴呆（VD）大鼠海马神经元凋亡相关蛋白的影响，探讨艾灸改善VD可能的机制。方法：从100只SD大鼠（剔除3只）中选取30只随机分为正常组和假手术组，每组15只。剩余67只大鼠采用双侧颈总动脉缺血再灌注法复制VD模型，将造模成功的45只大鼠随机分为模型组、艾灸组、西药组，每组15只。造模成功后第7天，艾灸组悬灸“关元”“命门”“大椎”穴，每穴15 min，每日1次，艾灸6 d后休息1 d，连续4周。西药组予尼莫地平灌胃，每天2 mg/kg，每日3次，连续4周。分别于干预前后采用Morris水迷宫实验检测各组大鼠逃避潜伏期；干预后，采用TUNEL法检测大鼠海马CA1区神经元凋亡率，免疫荧光双标法检测大鼠海马CA1区B淋巴细胞瘤-2（Bcl-2）/神经元核抗原（NeuN）、Bcl-2相关X蛋白（Bax）/NeuN共表达阳性细胞数，免疫荧光单标法检测大鼠海马CA1区细胞色素C（cytC）、线粒体外膜受体Tom20（Tom20）蛋白表达，Western blot法检测大鼠海马组织p53基因上调凋亡调控因子（PUMA）蛋白表达。结果：干预前，与正常组、假手术组比较，模型组、艾灸组、西药组大鼠逃避潜伏期延长（P<0.01）。干预后，艾灸组、西药组大鼠逃避潜伏期均较干预前缩短（P<0.01）；与模型组比较，艾灸组、西药组大鼠逃避潜伏期缩短（P<0.05）；与西药组比较，艾灸组大鼠逃避潜伏期缩短（P<0.05）。与正常组、假手术组比较，模型组大鼠海马CA1区神经元凋亡率升高、Bcl-2/NeuN共表达阳性细胞数减少、Bax/NeuN共表达阳性细胞数增多（P<0.01）；与模型组比较，艾灸组、西药组大鼠海马CA1区神经元凋亡率降低、Bcl-2/NeuN共表达阳性细胞数增多、Bax/NeuN共表达阳性细胞数减少（P<0.01）；与西药组比较，艾灸组大鼠海马CA1区神经元凋亡率降低、Bcl-2/NeuN共表达阳性细胞数增多、Bax/NeuN共表达阳性细胞数减少（P<0.01，P<0.05）。与正常组、假手术组比较，模型组大鼠海马CA1区cytC、Tom20蛋白及海马组织PUMA蛋白表达增多（P<0.01）；与模型组比较，艾灸组、西药组大鼠海马CA1区cytC、Tom20蛋白及海马组织PUMA蛋白表达减少（P<0.01）；与西药组比较，艾灸组大鼠海马CA1区cytC、Tom20蛋白及海马组织PUMA蛋白表达减少（P<0.05，P<0.01）。结论：艾灸可改善VD大鼠认知功能，可能与降低海马Bax、cytC、Tom20及PUMA蛋白表达，促进Bcl-2释放，抑制海马神经元凋亡有关。.
Keywords: apoptosis; moxibustion; proteins related with apoptosis; vascular dementia (VD).