本研究旨在观察六味地黄(Liu Wei Dihuang,LWDH)对D-半乳糖(D-galactose,D-gal)致衰老大鼠的学习记忆能力及中枢胆碱能神经系统的保护作用。采用成年Sprague-Dawley(SD)大鼠64只,雌雄各半。雄性、雌性大鼠均随机分为4组(n=8):空白对照组即生理盐水+生理盐水(N+N)组;对照组即生理盐水+LWDH(N+L)组;模型组即D-gal+生理盐水(D+N)组和治疗组即D-gal+LWDH(D+L)组。D+N组和D+L组连续每天项部皮下注射D-gal(100mg/kg)6周,N+N和N+L组大鼠注射相同体积生理盐水。第三周起给D+L和N+L组大鼠连续每天LWDH汤剂灌胃6周,同时给N+N组和D+N组连续每天相同体积生理盐水灌胃6周。D-gal衰老大鼠造模结束后,采用Morris水迷宫测定大鼠学习、记忆能力,用HE染色法观察海马和视皮质的形态学变化,检测视皮质中乙酰胆碱(acetylcholine,ACh)含量,以及胆碱乙酰转移酶(choline acetyltransferase,ChAT)及乙酰胆碱酯酶(acetylcholinesterase,AChE)的活性,用免疫组织化学方法观察视皮质中胆碱能神经元ChAT、AChE的表达。结果显示:与N+N组相比,D+N组表现出明显的学习记忆能力下降,提示D-gal衰老模型建立成功;D+L组逃避潜伏期显著缩短,游泳速度明显增加,同时其对靶象限搜寻时间百分比和平台穿越次数均显著增加,提示LWDH显著改善了D-gal诱导的学习记忆障碍。LWDH显著地增加了D+L组的视皮质匀浆ACh含量和ChAT活性,而降低了AChE活性。免疫组织化学结果显示:D+L组视皮质神经元AChE和ChAT均明显高于D+N组。HE染色结果显示:与N+N组相比,D+N组海马和视皮质神经元凋亡增加,细胞密度明显下降,而LWDH显著地增加了D+L组神经元密度。LWDH对衰老雌、雄大鼠的神经保护作用存在差异,D+N组雄性大鼠平台穿越次数的改善情况优于雌性大鼠,而雌性大鼠在ChAT表达水平和视皮质神经元密度指标上的改善情况则优于雄性大鼠。以上结果表明,LWDH显著逆转了D-gal诱导的学习记忆能力障碍及海马和视皮质的神经元损伤,其保护的机制可能是通过恢复视皮质中ACh的含量及ChAT活性,提高视皮质中ChAT及AChE的表达而起作用。此外,LWDH对大鼠大脑的保护作用有性别差异。 The purpose of this study was to observe the learning and memory abilities and central cholinergic system protection of Liuwei Dihuang (LWDH) on aging rats induced by D-galactose (D-gal). Sixty-four adult Sprague-Dawley (SD) rats were used, half male and half female. The male and female rats were randomly divided into 4 groups (n = 8): the blank control group was saline + saline group; the control group was saline + LWDH (N + L) group; D-gal + saline group and D-gal + LWDH (D + L) group. Rats in D + N and D + L groups were injected subcutaneously with D-gal (100 mg / kg) for 6 weeks. Rats in N + N and N + L groups were injected with the same volume of normal saline. From the third week, rats in D + L and N + L groups were treated with LWDH decoction continuously for 6 weeks, and the rats in N + N and D + N groups were given the same volume of saline for 6 weeks continuously. After D-gal aging rats were finished modeling, Morris water maze was used to measure the learning and memory ability of rats. The morphological changes of hippocampus and visual cortex were observed by HE staining, and the content of acetylcholine (ACh) The activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) were detected by immunohistochemistry. The expressions of ChAT and AChE in cholinergic neurons of the visual cortex were observed by immunohistochemistry. The results showed that compared with N + N group, D + N group showed a significant decrease in learning and memory ability, suggesting that D-gal aging model was established successfully; escape latency of D + L group was significantly shortened and swimming speed was significantly increased The target quadrant search time percentage and the number of platform traversal were significantly increased, suggesting that LWDH significantly ameliorated D-gal-induced learning and memory impairment. LWDH significantly increased ACh content and ChAT activity in visual cortex homogenate of D + L group, and decreased AChE activity. Immunohistochemistry results showed that: AChE and ChAT in D + L group were significantly higher than D + N group. HE staining showed that compared with N + N group, apoptosis of hippocampus and visual cortex neurons in D + N group increased and cell density decreased significantly, while LWDH significantly increased neuronal density in D + L group. The neuroprotective effects of LWDH on aging female and male rats were different. The improvement of plateau crossing number of male rats in D + N group was better than that of female rats, while the expression of ChAT and visual cortical neuron density index in female rats Improvement is better than male rats. The above results show that LWDH significantly reverses D-gal-induced learning and memory impairment and neuronal damage in the hippocampus and visual cortex, and its protective mechanism may be through the restoration of ACh content and ChAT activity in the visual cortex, and improve the visual cortex ChAT And AChE expression and play a role. In addition, LWDH has a protective effect on the brain of rats with gender differences.