[Effect of acupuncture intervention on hippocampal neuron loss and astrocytosis in SAMP 8 mice]

Abstract

Objective: To observe the effect of "Sanjiao Acupuncture Therapy" on hippocampal selective neuron loss and astrocytosis in senile accelerated mice (SAM) so as to reveal its mechanism underlying improvement of Alzheimer's disease (AD).

Methods: A total of 18 seven-month old male SAM prone 8 (SAMP 8) were selected and randomly allocated into model group, acupuncture group, and non-acupoint group. Moreover, 6 age- and sex-matched SAM resistant 1 (SAMR 1) were enrolled as the homology normal control group. For mice of the acupuncture group, "Sanjiao Acupuncture Therapy" [manual acupuncture stimulation of "Danzhong" (CV 17), "Zhongwan" (CV 12), "Qihai" (CV 6), "Zusanli" (ST 36) and "Xuehai"(SP 10)] was given, and for rats of the non-acupoint group, manual acupuncture stimulation was applied to bilateral costal region (non-acupoints, below the costal region and 10 and 15 mm superior to the iliac crest). The treatment was conducted once daily for 14 days. At the end of each experiment, the mouse's hippocampus tissue was taken out after routine perfusion and fixing for paraffin sections which were stained by toluidine blue technique for observing changes of neurons and by immunohistochemistry for analyzing glial fibrillary acidic protein (GFAP) immunoactivity of astrocytes.

Results: Compared with the control group, a marked neuron loss was found in the model, acupuncture and non-acupoint groups (P < 0.01). The numbers of neurons of hippocampal CA 1 and CA 3 regions in the acupuncture group were significantly more than those in the model group (P < 0.05). Compared with the control group, the expression level of hippocampal GFAP was markedly increased in the model group (P < 0.01). In comparison with the control group, the average expression area, optical density values and the number of GFAP-labeled astocytes were significantly upregulated in the model group (P < 0.01). While in comparison with the model group, these 3 indexes were apparently downregulated in the acupuncture group (P < 0.01) but not in the non-acupoint group except the average expression area, suggesting a reduction of hippocampal astrocyte activity after acupuncture intervention. A negative correlation was found between the expression level of GFAP and the number of astrocytes.

Conclusion: "Sanjiao Acupuncture Therapy" can lower or delay neuron loss, suppress astrocytosis, and regulate the relationship between neuron and astrocyte, which may contribute to its function in relieving AD.