电针对记忆障碍大鼠行为学及海马细胞因子的影响

目的:研究电针对D-半乳糖致衰老大鼠学习记忆障碍和海马中白介素-1β(IL-1β)、白介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)水平的影响,探索电针改善学习和记忆的作用机制。方法:将27只SD大鼠随机分成3组:①正常对照组(简称对照组,n=9),②记忆障碍模型组(简称模型组,n=8),③模型+电针组(简称电针组,n=10)。采用腹腔注射D-半乳糖的方法建立记忆障碍衰老大鼠模型。电针组给予电针治疗,选用“百会”、双侧“足三里”穴位,电针参数为3Hz的连续波,电流强度约1mA左右,持续20min,隔天1次。治疗21d后采用Morris水迷宫观察大鼠行为学变化,放射免疫分析方法检测大鼠海马中IL-1β、IL-6和TNF-α的水平。结果:模型组与对照组相比水迷宫测试中的逃避潜伏期明显延长,距离百分比明显降低(P<0.05,P<0.01);而电针组与模型组相比潜伏期明显缩短,距离百分比明显增大(P<0.01)。模型组海马中IL-1β、TNF-α水平明显高于对照组(P<0.05,P<0.01),IL-6水平则低于对照组(P<0.01);电针可显著下调海马组织中IL-1β、TNF-α水平(P<0.05)。结论:电针可改善由D-半乳糖致衰老大鼠学习记忆能力,其作用机制之一可能与大鼠海马组织中细胞因子的水平有关。

Effect of Electroacupuncture on Ethology and Cytokines of Hippocampus in Rats with Dysmnesy

OBJECTIVE: To observe the effect of electroacupuncture (EA) on learning and memory impairment and cytokines of hippocampus in aging rats induced by D-galactose for exploring its underlying mechanism in the treatment of dysmnesy. METHODS: A total of 27 SD rats were randomly divided into control group (n = 9), model group (n = 8) and EA group (n = 10). Dysmnesy model was induced by intraperitoneal injection of D-galactose. EA (3 Hz, continuous waves, 1 mA) was applied to "Baihui" (GV 20) and "Zusanli" (ST 36) for 20 min every time and on alternate days, continuously for 21 days. Morris water maze tests were conducted to detect the rat's escape latency, percentage of swimming distance in the original platform quadrant and the total distance (SD/TD) and the percentage of swimming time in the platform quadrant after removal of the platform (spatial probe test) which were used for assessing the animals' learning and memory ability. The contents of IL-1beta, IL-6 and TNF-alpha in the hippocampus tissue were assayed by radioimmunoassay. RESULTS: Location navigation test showed that the escape latencies on the 2nd day and the 3rd day in model group were significantly longer than those of control group (P < 0.05), and the percents of SD/TD and swimming time in the platform quadrant were significantly lower than those of control group (P < 0.05, P < 0.01). In comparison with model group, the escape latency of EA group on the 3rd day was significantly shorter (P < 0.05), and the percent of SD/TD in the platform quadrant of EA group was significantly longer (P < 0.01). Compared with control group, IL-1beta and TNF-alpha contents in the hippocampus increased significantly in model group (P < 0.05, P < 0.01), while IL-6 content in model group decreased significantly (P < 0.01). In comparison with model group, the levels of IL-1beta and TNF-alpha in EA group decreased significantly (P < 0.05). CONCLUSION: EA can improve the learning-memory ability in dysmnesy rats, which may be closely associated with its effects in regulating the levels of cytokines in the hippocampus.