Objective: To investigate the effect of "Huayu Tongluo" (resolving blood stagnation to dredge meridian-collaterals) moxibustion on remyelination and Sonic Hedgehog (Shh) signaling pathway in the corpus callosum of vascular dementia (VD) rats, so as to explore its mechanisms underlying improvement of VD.
Methods: Male Wistar rats were randomized into sham-operation, model, medication and moxibustion groups, with 12 rats in each group.The VD model was established by bilateral common carotid artery occlusion. Moxibustion was applied to "Shenting"(GV24), "Baihui"(GV20) and "Dazhui"(GV14) for 20 min once a day, 7 d as a treatment course, for 3 courses, with one day's rest between every two courses. Rats of the medication group were treated by gavage of 10 mg/kg of chloromastine solution once a day, and the course of treatment was the same as that of the moxibustion group. The rat's learning-memory ability was assessed by Morris water maze test (escape latency). The neurological deficits were evaluated by using Longa's scale.The mRNA and protein expressions of Shh and Gli1 in the corpus callosum were measured by quantitative real-time fluorescence PCR and Western blot, separately. The ultrastructure of the myelin sheath and myelinated axons was observed under transmission electron microscopy (TCM).
Results: Compared with the sham-operation group, the neurologic score and escape latency were significantly increased and prolonged (P<0.01), and the mRNA and protein expression levels of Shh and Gli1 and the number of myelinated axons were obviously decreased in the model group (P<0.01). In comparison with the model group, the escape latency was apparently shortened (P<0.05), while the mRNA and protein expression levels of Shh and Gli1 as well as the number of myelinated axons were strikingly increased in both moxibustion and medication groups (P<0.01). Results of TCM showed that in the model group, the arrangement of myelin coil structures was sparse and fuzzy, and some structures were bulged and disbanded. The oligodendrocytes were irregular, and the number of myelin sheath was rare. These situations were relatively milder in both moxibustion and medication groups.
Conclusion: "Huayu Tongluo" moxibustion can promote the differentiation and maturation of oligodendrocyte precursor cells after cerebral ischemia by regulating the expressions of Shh and Gli1 in Shh signaling pathway, thus promoting the regeneration of cerebral white matter myelin sheaths in VD rats, which may contribute to improving learning-memory ability.
目的：观察化瘀通络灸对血管性痴呆(VD)大鼠胼胝体髓鞘再生相关Sonic Hedgehog(Shh)信号通路中Shh配体和Gli1转录因子的影响，探讨化瘀通络灸促VD大鼠髓鞘再生的作用机制。方法：Wistar大鼠随机分为假手术组、模型组、艾灸组、西药组，每组12只，采用改良的双侧颈总动脉闭塞法复制VD大鼠模型。艾灸组予以“神庭”“百会”“大椎”化瘀通络灸法治疗，每日1次，每次20 min；西药组予氯马斯汀溶液(10 mg/kg)灌胃，每日2次；两组均7 d为1个疗程，共治疗3个疗程。Longa评分法评价各组大鼠神经功能损伤，Morris水迷宫实验检测各组大鼠学习记忆能力；实时荧光定量PCR法和Western blot法检测各组大鼠胼胝体中Shh、Gli1 mRNA和蛋白的表达；透射电镜法观察各组大鼠髓鞘超微结构和有髓神经轴突的数量。结果：与假手术组比较，模型组大鼠Longa评分显著升高(P<0.01)；与模型组比较，艾灸组与西药组Longa评分降低(P<0.05)。与假手术组比较，模型组大鼠逃避潜伏期明显延长(P<0.01)；与模型组比较，艾灸组及西药组大鼠逃避潜伏期显著缩短(P<0.01)。与假手术组比较，模型组Shh、Gli1 mRNA和蛋白相对表达量降低(P<0.01)；与模型组比较，艾灸组和西药组Shh、Gli1 mRNA和蛋白相对表达量升高(P<0.01)。与假手术组比较，模型组胼胝体区髓鞘线圈样结构离散、模糊并出现部分膨出和崩解，有髓神经轴突数量显著减少(P<0.01)，艾灸组和西药组髓鞘结构相比模型组得到明显修复，有髓神经轴突数量显著增加(P<0.01)。结论：化瘀通络灸可能通过调控Shh信号通路中Shh、Gli1的表达，促进脑缺血后少突胶质前体细胞的分化与成熟，从而促进VD后大鼠脑白质髓鞘再生，恢复脑白质功能。.
Keywords: Huayu Tongluo moxibustion therapy; Remyelination; Sonic Hedgehog signaling pathway; Vascular dementia.