针刺防治糖尿病性学习记忆障碍

Study on the Effect of Acupuncture in the Prevention and Treatment of Learning-memory Decline in Diabetes Mellitus Rats

目的 :研究针刺对链脲佐菌素致糖尿病大鼠学习记忆障碍的防治作用。方法 :在箱底有金属栅栏的跳台箱内训练大鼠。以主动回避反应作为学习记忆能力指标。训练时 ,短声信号先出现 5sec,然后结合脚掌电击 1 0sec,大鼠能在声信号期内跳上绝缘平台主动回避电击被认为条件反射建立。海马薄片LTP记录 :在海马CA1 区记录由刺激Scheffer侧支诱发的突触后群峰电位(PS) ,并观察高频刺激 ( 1 0 0Hz,1sec)引起的长时程增强效应 (LongTermPotentiation ,LTP) ,作为突触可塑性的指标。结果 :糖尿病大鼠在跳台训练中正确建立条件反射的百分率明显低于正常组 (P <0 .0 5) ,而针刺组显著优于糖尿病组 (P <0 .0 5)。糖尿病组LTP效应较正常组明显减弱 (P<0 .0 0 1 ) ,针刺组较糖尿病组明显改善 (P <0 .0 5)。结论 :糖尿病大鼠在行为学和海马LTP记录中均表现出学习记忆能力的损害 ,针刺治疗在一定程度上可增强神经可塑性 。

Objective:The effects of acupuncture treatment on learning and memory decline were studied in diabetes mellitus (DM) rats. Methods: Streptozotocin induced diabetic rats were trained to make an active avoidance reaction (index of learning memory) in a compartment equipped with a grid floor through which an electric shock (40 V) was delivered. The training started with sound signal (5 sec), then combined with foot shock for 10 sec. If the rats jumped onto the insulated platform located in the middle of the grid floor to avoid foot shock within 5 sec, the conditioned reflex was considered to have been established. In vitro experiments, the post synaptic population spikes (PS) were recorded from CA 1 area of the hippocampus in the prepared hippocampal slices by stimulating the Schaffer collateral pathway. Following a high frequency tetanic stimulation (100 Hz), the PS was augmented and lasted for 2 hours, that is called as long term potentiation (LTP) and used as an index of synaptic plasticity. In vivo study, 12 male Wistar DM rats were randomly and evenly divided into model group and acupuncture group, other 6 normal rats were attributed to normal control group. 'Zusanli' (ST 36), 'Pishu' (BL 20), 'Shenshu'(BL 23) and 'Sanyinjiao'(SP 6) were punctured and stimulated with uniform reinforcing reducing technique. Results: The correct rates for establishing the conditioned reflex in 40 times of training in normal control group, model group and acupuncture group were 44.8±16.4%, 17.0±17.9% and 45.5±17.3% respectively, showing that the correct rate of model group is significantly less than that of normal control group ( P <0.05), while that of acupuncture group is significantly higher than that of model group ( P <0.05). It suggests that the learning memory ability of DM rats declined remarkably and was improved after acupuncture treatment. Results of vitro study showed that the mean values of the amplitude and slope of PS in responding to high frequency stimulation in normal control, model and acupuncture groups increased by 180.8±8.4% and 214.5±6.6%, 124.9±6.2% and 141.3±11.5%, 146.4±4.5% and 177.2±8.6% respectively, which displayed that LTP was reduced and shortened considerably ( P <0.001) in DM rats, but markedly improved ( P <0.05) in acupuncture group. Conclusion: Both the learning memory ability and hippocampal LTP were severely impaired in DM rats. After acupuncture treatment, the hippocampal synaptic plasticity was enhanced apparently and the learning memory decline was also improved significantly.