OBJECTIVETo observe and explore the antagonism of rhizoma gastrodiae (RGT) to the impairment of learning and memory ability induced by lead in rats.

METHODS36 Wistar rats were randomly divided into 3 groups, 12 rats in every group, (1) control group: treated with distilled water; (2) lead group: treated with lead acetate (0.1 g.kg-1.d-1); (3) lead-RGT group: lead acetate (0.1 g.kg-1.d-1) + RGT(4.0 g.kg-1.d-1). The ability of learning and memory of the rats was measured monthly by swimming test; 3 months later, the rats were decapitated and nitric oxide(NO) and total antioxidative capacity(TAOC) in hippocampus were measured immediately and the examination for pathology was also made.

RESULTS(1) In swimming test, the number of seeking for anchorage in lead group(1, 2, 3 month: 10.10 +/- 1.10, 7.80 +/- 1.32, 5.40 +/- 0.97 respectively) were significantly decreased, compared with the control(P < 0.01); the number of seeking for anchorage in RGT-lead group(1, 2, 3 month: 11.90 +/- 0.95, 10.90 +/- 0.95, 9.70 +/- 0.96 respectively) were significantly increased, compared with lead group(P < 0.01). (2) NO (0.733 +/- 0.015) mumol/g pro and TAOC (0.945 +/- 0.017) U/mg pro in hippocampus of lead group were significantly decreased compared with the control(P < 0.01) whereas NO(0.769 +/- 0.021) mumol/g pro and TAOC(0.986 +/- 0.010) U/mg pro in hippocampus of RGT-lead group were significantly increased compared with lead group(P < 0.01). (3) Pathological examination showed that in lead group, marked atrophy in hippocampus, cellular denaturation and necrosis, dissolution and disappearance in axon were found. In lead-RGT group, the atrophy of hippocampus was not obvious, the cell morphology was nearly normal, no obvious abnormal changes were seen.

CONCLUSIONRGT is antagonistic to the impairment of hippocampus and of learning and memory ability induced by lead.