[Effect of electroacupuncture combined with Ginkgo biloba extract (GBE 50) on learning-memory ability and hippocampal cytokine levels in rats with dysmnesy].

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.