[Effect of Moxibustion on Learning-memory Ability and Hippocampal Amyloid beta Protein Overexpression in Mild Cognitive Impairment Rats].

Objective: To observe the effect of moxibustion of "Baihui" (GV 20), etc. on learning-memory ability, hip- pocampal amyloid beta (AP) protein expression and immune activity in mild cognitive impairment (MCI) rats, so as to reveal its mechanism underlying improving cognitive impairment.

Methods: A total of 48 SD rats were randomly divided into normal, model, moxibustion, and medication groups (n = 12 in each group). The MCI model was established by intraperitoneal injection of 2 mL mixture solution containing D-galactose (120 mg - kg- - d-) and Sodium Nitrite (90 mg x kg(-1) x d(-1)), once daily for 40 days. Moxibustion (separated by Radix Aconiti Praeparata cake) was applied to "Baihui" (GV 20), "Fengfu" (GV 16) and "Dazhui" (GV 14) for 20 min, once daily for 2 weeks, with one day's rest between two weeks. The rats of the medication group were given with Nimodipine (2 mg x kg(-1) x d(-1), t.i.d.) by lavage for 2 weeks (except Sundays). The learning-memory ability was detected by Morris maze water swimming tasks. The expression level of hippocampal AP protein was detected by immunohistochemistry, and those of hippocampal presenilin-1 (PS-1) mRNA and cleaving enzyme (BACE-1) mRNA were detected by real time-PCR, and serum IL-6 level was assayed by ELISA.

Results: Following modeling, the average escape latency of location navigation tests of Morris maze water swimming tests, the expression levels of hippocampal Abeta protein, PS-1 mRNA and BACE-1 mRNA, and serum IL-6 content were significantly increased in the model group( P<0.01) , while the target-platform crossing times and the percentage of target-quadrant swimming duration of spacial probe trials were remarkably decreased in the model group (P<0.01). After moxibustion, the increased escape latency, hippocampal AP protein, PS-i mHNA and BACE-1 mRNA ex- pression and serum IL-6 content, and the decreased target-platform crossing times and the percentage of target-quadrant swim- ming duration were reversed in both moxibustion and medication groups (P<0.01). The effects of the moxibustion group were obviously superior to those of the medication group in decreasing the escape latency, and in up-regulating the target-platform crossing times, the percentage of target-quadrant swimming duration, and down-regulating hippocampal Abeta protein, PS-1 mHNA and BACE-1 mRNA expression levels and serum IL-6 content (P<0.05).

Conclusion: Moxibustion is effective in improving MCI rats' learning-memory ability, which may be associated with its functions in down-regulating the levels of hippocampal Abeta protein, PS-1 mRNA and BACE-1 mRNA expression and serum IL-6 content, possibly by blocking Abeta overexpression-induced inflammation cascade.