大鼠低剂量长期摄入麻痹性贝毒的毒性研究

目的：探询麻痹性贝毒(PSP)可能存在的蓄积毒性作用和远期毒性，为全面认识PSP危害提供参考和依据。 方法： 从市售易染毒贝类海产品中提取麻痹性贝毒，小鼠法确定提取液毒性。连续进行大鼠灌胃染毒5周，停毒24 h及10 d后取大鼠血样进行电解质与肝、肾、心等重要脏器功能的检测；取尿样作一般尿液指标分析；重要组织切片后，用常规苏木素伊红（HE）染色后进行光镜检察。 结果： 低剂量组（PSP，4.6 μg STX/kg）大鼠的主要器官功能未见损害；中剂量组（9.2 μg STX/kg）肾功能指标出现异常，其余脏器功能正常；高剂量组（18.4 μg STX/kg）肝、肾、心功能等均存在不同程度的损害，显示出一定的功能毒性。病理学检查发现，高剂量组大鼠胸腺、脾脏脏器系数略有增大；肝组织细胞疏松、肾结构有些模糊不清，伴炎性改变；骨骼肌纤维有断裂现象；恢复期及其余组未见明显异常。 结论： 中、高剂量PSP对机体存在一定的毒性，且以高剂量组为重，表明PSP在大鼠体内有一定的累积作用，长期摄入低剂量PSP对机体有一定的损害。因此，长期食用PSP轻度污染的海产品（PSP含量低于食品安全标准）可能并不安全。

Toxicity of long-term intake of PSP at low level from shellfish on rats

AIM: In order to investigate the possible cumulative and chronic toxicity of paralytic shellfish poisoning (PSP) and provide more information on toxicity of PSP. METHODS: The sub-acute toxicity of PSP was evaluated in the rat. PSP was extracted from the seafood in market, and the toxicity of the extract was determined by mouse bioassay. The extracts in different toxicity were administrated to rats through gastrotube for 35 days. The biochemical and pathological changes in vital tissues in rats were examined by the detections of some function indexes in blood and urine and the observations under optical microscope during both the exposure period and the subsequent 10-day withdrawal term. RESULTS: No biochemical and pathological changes in tissues occurred for the control and low-dose group (4.6 μg STX/kg), whereas some changes happened for the middle (9.2 μg STX/kg) and high groups (18.4 μg STX/kg). In experiment, some renal function indexes changed in the mid-dose group, and some of the cardiac, hepatic and renal functions indexes altered for the high dose group with some changes in weight of the thymus gland and spleen. What is more, the liver and kidney became indistinct with some inflammatory changes, and some muscles had ruptured for the 40% rats in high-dose group. CONCLUSION: These results suggest that long-term intake of PSP at a concentration, which doesn't exceed the threshold of standard, has some toxicity on rats, and that the toxicity of PSP has an accumulative effect. In a word, it is unsafe for us to eat frequently bivalve seafood polluted by PSP toxins.