Effects Of Quqianling On Impairment Of Learning And Memory In Lead-exposed Rats

Objective: Try to find an effective medicine to treat lead poisoning. Quqianling, made from Chinese traditional medicine, was observed its effect on eliminating lead and impairment of learning and memory in lead exposed rats.Methods: 30 male and 30 female SD rats (100¹30g) were divided into 6 groups randomly. 5 groups of rats were prepared to be lead intoxicated models by gavaging lead acetate (2.0%, Iml/l00g BW) for 3 weeks. One group of non-lead treated rats was observed as negative control group. Lead-treated rats were divided into five equal groups according to the blood lead levels. Three groups of rats were gavaged with high, mediumx low dose of Quqianling(lml/100g BW)for three weeks; one group of rats was treated with EDTA( 0.5%, ip, Iml/l00g BW)for three weeks; another group of rats was not treated and severed as positive control group. Effect of eliminating lead was measured with blood lead levels fluctuation; Behavior of learning and memory was evaluated by Morris water maze test; the changes of nitric oxide synthase (NOS) activity of hippocampus were observed by using NADPH-diaphorase histochemistry.Results: ( 1 ) Compared with normal rats, the blood lead levels in the lead-exposed rats were obviously raised (P < 0.01); the average latency to find the hidden platform in Morris water maze test was significantly lengthened (P < 0.05 ) ; the gain of body weight, open field behaviors and the average optical density of NOS positive neurons in DG,CA₁,CA₃ ofhippocampus were markedly reduced( P < 0.05 ). It showed that there were morphometric changes in the hippocampus of lead-exposed rats, which probably result in the impairment of learning and memory of lead-exposed rats. The lead intoxicated models were made perfectly.(2)The decline percent of blood lead in EDTA-treated and Quqianling-treated rats was significantly higher than that of positive control group (P < 0.05 ) ;There was no difference between EDTA group and Quqianling group (P>0.05). It indicated that Quqianling could eliminate lead as well as EDTA.(3)Compared with the positive control group, the average latency of EDTA and Quqianling group was evidently shortened (P < 0.05 ) . In the second turn of Morris water maze test, The average latency of Quqianling group was shorter than that of EDTA group (P < 0.05 ) .Furthermore, the retain percent of learning and memory of EDTA group and Quqianling group was obviously increased ( P < 0.01); the retain percent of learning and memory of the former was higher than that of the latter ( P < 0.05 ) . It was suggested that EDTA and Quqianling could improve disorder of learning and memory, and Quqianling had better effects.(4)Compared with the positive control group, the average optical density in the EDTA-treated and Quqianling-treated rats in DG,CA₁,CA₃ of hippocampus was apparently increased (P < 0.01 ) ; No difference between EDTA and Quqianling group. The result also demonstrated that the EDTA and Quqianling could improve the impairment of learning and memory in lead-exposed rats from morphometrics.Conclusions: From this experiment, we conclude that Quqianling is effective in eliminating lead; It can improve the impairment of learning and memory in lead-exposed rats and better than EDTA.