【摘要】 本文以文蛤(Meretrix meretrix)为实验对象,将其在不同浓度镉离子溶液(0、1.5 mg/L、3 mg/L、6 mg/L)中染毒5 d,并利用透射电镜技术分析文蛤肝胰腺细胞的超微结构变化。结果表明,镉离子对文蛤肝胰腺细胞超微结构的影响较大,主要表现在对内膜系统和线粒体的破坏上,其中线粒体嵴减少、肿胀变形、逐渐空泡化;粗面内质网由原先的板层状结构解体,形成许多大小不同的小泡。微绒毛脱落并逐渐减少,部分空泡化,高尔基体膜也有扩张的现象。膜性结构形成的空泡中出现沉积物,核膜出现内陷。镉离子破坏了文蛤肝胰腺细胞膜和主要细胞器的结构,影响了肝胰腺细胞的正常生理机能,随着镉溶液浓度的升高,对肝胰腺细胞结构的破坏性也增强。更多还原

【Abstract】 Cadmium( Cd) is one of the most toxic heavy metals that may alter the structure and cause histopathological changes at varying severity in various organs of aquatic animals. A large amount of cadmium may be accumulated rapidly but lost very slowly. Meretrix meretrix is a species which inhabits in the intertidal zone sediment and has a filter feeding lifestyle,easily polluted by heavy metals. The aims of this paper were to study the toxic effects of cadmiuin on the histopathological alterations of hepatopancreas cells in M. meretrix exposed to different concentrations of cadmium( Cd2 +,0,1.5 mg/L,3 mg/L and 6 mg/L). After 5 days experimental exposure,the ultrastructural changes of hepatopancreas cells of M. meretrix in Cd exposure groups and control group were observed using transmission electron microscopy( TEM). The results showed that the hepatopancreas of M. meretrix was composed of four kinds of cells,E cell,F cell,R cell and B cell. Acute cadmium poisoning caused remarkable changes in the ultrastructure of hepatopancreas cells compared with the control group. The nucleus( Plate Ⅰ: 5- 7),mitochondria( Plate Ⅰ: 8- 9,Plate Ⅱ: 1) and rough endoplasmic reticula( Rer)( PlateⅡ: 2- 4) of hepatopancreas cells were sensitive to acute Cd toxicity. The mitochondria in F cells of 1. 5 mg /L and 3 mg /L Cd2 +concentration groups became swelling( PlateⅠ: 8) andvacuolating( PlateⅠ: 9) gradually,some mitochondrial crista in R cells of 6 mg /L Cd2 +concentration group disintegrated( PlateⅡ: 1). Rough endoplasmic reticula disintegrated from the original layered plate( PlateⅠ:2),and formed vesicles in many different sizes in F cells of 3 mg /L Cd2 +concentration group( PlateⅡ: 3).Microvilli broke off and decreased gradually( PlateⅡ: 7- 9),and the vacuole appeared. Cytoplasm swelled and formed vacuoles which were filled with some sediment in B cells of 3 mg /L and 6 mg /L Cd2 +concentration group( PlateⅡ: 11- 12). With the increased concentration of Cd2 +,the nuclear morphology changed and the nuclear membrane invaginated( PlateⅠ: 6- 7),and the membrane of Golgi apparatus in F cells expanded( PlateⅡ: 6) too. The structure of most organelles and endomembrane system were destroyed by Cd2 +solution,which affected the normal physiological function of hepatopancreas cells. With the increased concentration of Cd2 +,the destruction of the hepatopancreas cells was also enhanced. It demonstrated that the intensity of these ultrastructural alterations was influenced by concentration of cadmium exposure. It could be inferred that the damage was caused by over oxidation. The morphological changes of these structures reflect changes in M.meretrix immune response capability caused by Cd exposure and provide basic information for the ecotoxicological research of the intertidal zone bivalve.更多还原