Objective: To observe the effect of electroacupuncture (EA) combined with Ginkgo biloba extract (GBE 50) on learning-memory ability and hippocampal cytokine contents in aging rats for exploring its underlying mechanism in the treatment of dysmnesy.
Methods: Forty-five SD rats were randomly divided into control (n=9), model (n=8), EA (n=10), GBE 50 (n=9) and EA + GBE 50 (n=9) groups. The dysmnesy model was established by D-galactose intraperitoneal injection for 42 days. EA (3 Hz, 1 mA) was applied to "Baihui" (GV 20) and "Zusanli" (ST 36) for 20 min, once every other day for 21 days. The learning-memory ability was detected by Morris water maze tests. The levels of IL-1beta, IL-6 and TNF-alpha in hippocampus were examined by radioimmunoassay.
Results: Compared with control group, the mean escape latency (MEL) of the rats in model group was significantly greater on the 2nd and 3rd day training (P<0.05, P<0.01), and the percent of swimming distance (PSD) in the target quadrant was shortened significantly (P<0.01). Compared with model group, the MEL values of the rats in EA, GBE 50 and EA + GBE 50 groups were significantly shortened (P<0.05, P<0.01), and the PSD values of the later 3 groups increased considerably (P<0.01). Comparison among the EA, GBE 50 and EA + GBE 50 groups showed that the MEL of EA + GBE 50 was obviously shorter than those of EA and GBE 50 groups (P<0.05). Compared with control group, the contents of IL-1beta) and TNF-alpha in hippocampus in model group increased significantly, but IL-6 decreased markedly (P<0.05, P<0.01). In comparison with model group, the IL-1beta contents of EA, GBE 50 and EA + GBE 50 groups, and TNF-alpha of EA and EA + GBE 50 groups were reduced significantly (P<0.05, P<0.01); and the contents of IL-6 in GBE 50 and EA + GBE 50 groups increased apparently (P<0.01). No significant differences were found between model and EA groups in IL-6 levels, and between model and EA + GBE 50 groups in hippocampal TNF-a levels (P>0.05).
Conclusion: Both EA and GBE 50 can improve the dysmnesy rats' learning-memory ability, which may be closely associated with their effects in regulating hippocampal IL-1beta, IL-6 and TNF-alpha levels to relieve the inflammatory reaction. Combined administration of EA and GBE 50 has a synergic effect.