急性与亚慢性镉胁迫对河南华溪蟹消化系统亚细胞结构的影响

Detrimental effects of cadmium on the subcellular structure of digestive system in the freshwater crab Sinopotamon henanense

本实验运用透射电镜技术,观察了河南华溪蟹(Sinopotamon henanense)分别在镉29.0 mg·L-1急性染毒4 d和2.90 mg·L-1亚慢性染毒21 d后消化系统4种器官(食道、中肠、后肠和肝胰腺)亚显微结构的变化和损伤情况.结果显示:急性和亚慢性染毒均可导致各组织中细胞核变形、染色质浓缩边集、核固缩、核碎裂,线粒体空泡化、嵴缩短、融解甚至消失,但前者对各组织亚细胞的损伤更为严重;肝胰腺和中肠组织的病理变化较食道和后肠组织中的明显,镉胁迫后均可观察到上皮细胞内粗面内质网扩张变形、核糖体脱落,高尔基体形态结构异常,微绒毛排列紊乱、部分融解、断裂,出现大量的自噬溶酶体;食道和后肠的肌纤维水肿、肌原纤维排列疏松.急性与亚慢性镉处理均会对河南华溪蟹的消化系统产生毒害,造成各组织器官中细胞结构的严重损伤,且急性高浓度的镉暴露对机体造成的毒性影响较为严重.这些损伤会影响消化酶的合成和分泌等生理功能,导致机体失去正常的消化能力.

The detrimental effects of cadmium（ Cd） on the subcellular structure of digestive system in the freshwater crab was examined by acutely exposing Sinopotamon henanense to 29. 0 mg·L-1Cd for 4 d and subchronically exposing to 2. 90 mg·L-1for 21 d. The changes in submicroscopic structures of esophagus,midgut,hindgut and hepatopancreas in S. henanense were documented through the transmission electron microscopy（ TEM）.Results showed that damages to the digestive system in the acute 29.00 mg·L-1Cd treatment group were more severe than those in the subchronic group.Further,examination of all the tissues revealed cytoplasmic hypervacuolization,nuclei deformation,condensation and margination of nuclear chromatin,swelling and lysis of mitochondrial membrane,and collapse of the mitochondria cristae in S. henanense after two sets of Cd treatment. In addition,the structure of microvilli,rough endoplasmic reticulum,lysosome as well as Golgi complex in epithelial cells of hepatopancreas and midgut were altered.Edema and loose muscle fiber bundle appeared in esophagus and hindgut. Both acute and subchronic Cd exposures can adversely affect the digestive system of S. henanense,and lead to a serious injury of the cellular structure. These damages would certainly affect the process of digestion,absorption,secretion and detoxification in the digestive system,resulting in an impairment of digestive function and reduced crab activities or even death of organisms.