不同时窗针刺对脑瘫幼鼠海马CA1区神经元及脑组织神经生长因子表达的影响

Effects of Acupuncture at Different Time-windows on the Injured Neurons of Hippocampal CA1 Area and NGF Expression in Cerebral Hypoxia-ischemia Rats

目的 :观察针刺在不同时期介入对缺血缺氧性脑瘫幼鼠的治疗作用 ,并探讨其神经生化机制。方法 :7日龄新生大鼠随机分为A、B、C、D 4组 ,A、B组分别于造模后 48h、7d开始针刺 ,C为模型组 ,D为假手术对照组 ;7、14、2 1d时进行行为测试 ,2 1d时观察各组死亡率 ,测定脑重量 ,并观察脑大体和海马CA1区神经细胞的损伤状况以及脑组织神经生长因子 (NGF)的表达情况。结果 :①针刺可提高动物的存活率 ,以A组最明显 ,死亡率较C组下降 2 1.8%。缺血缺氧后 7d ,模型组大鼠前肢功能明显下降 ,至 2 1d时 ,A、B、C 3组前肢功能均显著改善 ,A组基本接近正常水平 ,但C组仍差于D组。缺血缺氧后 2 1d ,A、B、C组左脑半球呈程度不等的萎缩 ,各组左大脑重量有显著性差异。 4个组右侧海马CA1区锥体神经元数无显著差异 ,左侧则差异显著。②造模后2 1d ,各组NGF表达存在程度上的差异 ,A组NGF呈强阳性表达的数量最多 ,其次为B组、C组。PBS空白对照组结果为阴性。结论 :①针刺可早期介入治疗脑瘫 ,提高存活率 ,改善前肢功能 ,增加脑重 ,促进大脑发育 ,但头针在早期宜慎用。②针刺提高缺血缺氧后海马神经元密度 ,增加NGF的长时程阳性表达 ,这可能是其治疗缺血缺氧性脑瘫的重要机制之一。

Objective: To observe the effects of acupuncture at different time-windows on hypoxic-ischemic cerebral palsy rats, and to study its underlying neurobiochemical mechanism. Methods: Eighty-five neonatal SD rats were randomized into control group (n=16), model group (n=23), acupuncture group-1 (n=23, acupuncture was given beginning 24 h after operation) and acupuncture group-2 (n=23, acupuncture was given beginning 8 days after operation). Cerebral palsy model was established by occlusion of the left common carotid artery and inhalation of 8% oxygen plus 92% nitrogen. “Baihui'(GV 20), Tempale-Point-1 (0.8 cm superior to the external auditory canal aperture), “Quchi'(LI 11), “Neiguan'(PC 6), “Zusanli'(ST 36) and “Yongquan'(KI 1) were punctured and the former two acupoints were stimulated electrically with an electroacupuncture apparatus. The death rate, forepaw-touching test (adhesive plaster tearing-off test), brain weight, neuronal number of hippocampal CA1 region were measured and the expression of nerve growth factor (NGF) in the brain was assayed with immunohistochemical method. Results: The death rates (13.0% and 21.7%) of both acupuncture group-1 and -2 were significantly lower than that (34.8%) of model group (P< 0.05). The duration values for tearing off adhesive-plaster on 7 d, 14 d and 21 d of acupuncture group-1 and on 14 d of acupuncture group-2 were markedly shorter than that of model group (P< 0.05), suggesting functional improvement of the rats' forelimbs. No significant difference was found among the 4 groups in the left brain weight (P<0.001). The number of neurons of hippocampal CA1 region on the left side was biggest in control group, bigger in acupuncture group-1, smaller in acupuncture group-2 and smallest in model group respectively. Twenty-one days after operation, the number of NGF immunoreaction (IR) strongly-positive neurons in the cerebral cortex, straiate body and hippocampus was biggest in acupuncture group-1, bigger in acupuncture group-2 and smaller in model group, and only very weakly IR-positive neurons were found in control group. Conclusion: ① Acupuncture can upregulate the long-term expression of NGF in the brain, which may contribute to the effect of acupuncture in improving cerebral palsy. ② Acupuncture therapy may be used to treat cerebral palsy at the early stage and can reduce hypoxia-ischemia induced injury of cerebral neurons.