穴位埋线对衰老模型大鼠慢性应激下海马神经元结构的影响

Effect of Acupoint Catgut-embedding Therapy on Changes of Structure of Hippocampal Neurons in Senile Chronic Stress Rats

目的:通过观察穴位埋线对衰老模型大鼠慢性应激下海马神经元结构的影响,探讨慢性应激对衰老机体的促衰老作用及穴位埋线的抗衰机制。方法:雄性SD大鼠随机分为空白组、衰老组、应激组、埋线组,每组12只。采用D-半乳糖溶液腹腔注射制作衰老模型,采用长期制动应激造成慢性应激,埋线组分别于"百会""肾俞""内关""肝俞"交替埋线8次,1次/周。HE染色,于光镜下对大鼠海马锥体细胞进行计数,并于电镜下观察海马神经元细胞结构的变化。结果:光镜下空白组大鼠海马锥体细胞排列整体密集,形状规则;衰老组大鼠海马锥体细胞排列较稀疏;应激组海马锥体细胞排列稀疏,形态不规则;埋线组大鼠海马锥体细胞排列较密集。衰老组、应激组大鼠海马锥体细胞数量明显少于空白组(P<0.05,P<0.01),应激组与衰老组相比,其海马锥体细胞数量减少更为显著(P<0.01),而埋线组海马锥体细胞数量明显升高(与应激组比较P<0.01)。电镜下观察,空白组神经元形态正常,衰老组神经元体积明显缩小,应激组神经元呈现极度不规则形态,埋线组的神经元异常形态得到明显改善。结论:衰老模型大鼠的海马神经元数量和结构呈现增龄性老化现象,慢性应激可加重对海马神经元的损害,加速脑衰老;穴位埋线可拮抗应激性衰老机体海马神经元的进一步损害,从而延缓脑衰老。

Objective To observe the effect of chronic stress stimulation on aging and the effect of acupoint catgut-em- bedding therapy on structural changes of hippocampal pyramidal neurons in senile chronic stress rats, so as to reveal its mecha- nisms underlying resisting senility. Methods Forty-eight male SD rats were randomly divided into normal control, senility mo- del, senility＋ stress and senility＋ stress＋ catgut-embedding （catgut-embedding） groups （n -- 12 in each group）. Senility model was established by intraperitoneal injection of D-galactose liquor, once daily for 8 weeks; and chronic stress was produced by re- stricting the rat in an inmovable cylinder for 1 -4 h progressively, once daily for 4 weeks. Catgut embedment （0.4- 0.6 cm in length） was applied to “Baihui” （GV 20） and “Shenshu” （BL 23）, “Neiguan” （PC 6） and “Ganshu” （BL 18） alternatively by u- sing a surgical needle, once a week, 8 weeks altogether. The brain tissue containing hippocampus was cut into sections to be stained with H.E. technique, and the number of the hippocampal pyramidal neurons of CA 3 region was counted under optical mi- croscope. The ultrastructure of pyramidal neurons in the left CA 3 region of the hippocampus was observed by electron microscope （2 rats for each group）. Results Compared with the normal control group, the numbers of hippocampal pyramidal neurons in the senility model group and senility＋ stress group were remarkably decreased （P^0.05, P〈0.01 ）. The number of pyramidal neurons was obviously fewer in the senility ＋ stress group than in the senility model group （P〈0, 01）. In comparison with the se- nility＋ stress group, the number of pyramidal neurons in the catgut-embedding group was considerably increased （P〈0.01 ）. Re- suits of optical microscope showed that the pyramidal cells were sparse in the senility model and very sparse in the senility ＋stress group, and relatively richer in the catgut-embedding group. Findings of the electron microscope displayed that the pyramidal neurons presented an injured state including shrank soma, pyknosis of the cellular nucleus, atrophia of nucleoli, onglobation of in- tranuclear caryotin, decreased glycogen granules, etc. in the senility model group, and an extremely irregular shape, partial apo- ptosis, severer pyknosis of the cellular nucleus, more edema blank regions, etc. in the senility＋ stress group. These situations of pyramidal cells in the hippocampal CA 3 region were relatively milder in the catgut-embedding group. Conclusion Chronic stress may aggravate the damage of hippocampal pyramidal neurons in senile rats, which can be improved by catgut-embedding therapy.