Effect of Arsenic in Realgar on Rat Ability in Novel Objects Recognition Test / 中国实验方剂学杂志

ABSTRACT

Objective:To determine the contents of inorganic arsenic（iAs），monomethylarsonic acid（MMA） and dimethylarsinic acid（DMA） in brain tissues and blood by using hydride generation-cold trap-atomic absorptionspectrometry（HG-CT-AAS）， and to explore the toxic effects of Realgar on central nervous system of rats. Method:The 96 Wistar rats were randomly divided into 4 groups：normal control group，0.3，0.9 and 2.7 g·kg^-1 Realgar groups. They then received intragastric administration for 14，28 and 42 days respectively， so a total of 12 groups were formed， with 8 animals in each group. The normal group was given the same dose of sodium carboxymethyl cellulose （CMC-Na） by gavage. The contents of iAs，MMA and DMA in blood and brain tissues were determined by HG-CT-AAS. The novel object recognition test was conducted to observe the learning and memory ability of rats. The changes of hippocampal neuron ultrastructure were observed by transmission electron microscopy. Result:There was no difference in the growth，weight and hippocampal coefficient of the experimental animals. The method of HG-CT-AAS showed a good linearity，precision，accuracy and recovery in content determination of arsenic （at various forms） in rat brain and blood. MMA and DMA were detected in the brain of realgar groups at time-dose-effect relationship. iAs，MMA and DMA were detected in the blood of Realgar groups. The nuclear membrane， mitochondria and endoplasmic reticulum in hippocampus neurons of rats were gradually damaged with the increase of Rhubarb exposure dose and time. After 14 days of exposure to Realgar，compared with the normal control group，there was no significant difference in the novel object recognition index among Realgar groups. After 28 days of exposure，only 2.7 g·kg^-1 Realgar group showed statistically significant difference with the control group （<italic>P</italic><0.05）. After 42 days of exposure， the novel object recognition index of 0.9 and 2.7 g·kg^-1 Realgar groups was significantly lower than that in normal control group（<italic>P</italic><0.05）. Conclusion:The metabolites of Realgar in rats are iAs，MMA and DMA. MMA and DMA can be accumulated in the brain tissue through the blood-brain barrier，causing the decline of the ability of learning and memory and leading to damage of hippocampal neurons.