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研究报告

Critical roles of calcium signaling in cadmium-induced apoptosis in the freshwater crab Sinopptamon henanense

基金项目：国家自然科学基金（No.31272319）；高等学校博士学科点专项科研基金联合资助课题（博导类）（No.20111401110010）；中国博士后科学基金面上项目（No.2012M510774）

摘要：以河南华溪蟹（Sinopptamon henanense）为研究材料，采用生理生化和酶学组织化学等方法，通过不同时间（12、24、48、72和96 h）不同镉浓度（0、14.5、29、58 mg·L^-1）处理，首先研究了镉对肝胰腺细胞内钙调素（CaM）含量、钙ATP酶（Ca²⁺-ATPase）活性和细胞凋亡的影响；然后用Ca²⁺抑制剂EGTA和LaCl₃预处理河南华溪蟹后再进行镉处理，以分析Ca²⁺信号对镉诱导肝胰腺细胞凋亡的影响.结果显示，镉处理引起肝胰腺细胞CaM含量和Ca²⁺-ATPase活性显著升高，并且Caspase-3和Caspase-9被激活.用Ca²⁺抑制剂EGTA和LaCl₃预处理华溪蟹4 h后，再用镉处理48 h，镉诱导的肝胰腺细胞Caspase-3和Caspase-9活性上升都被阻断.结果表明：镉处理引起河南华溪蟹肝胰腺细胞Ca²⁺浓度发生变化，并通过CaM等信号分子调控Caspase-3/9活性，进而引发细胞凋亡.

Abstract：Using the freshwater crab Sinopotamon henanense as a model organism, we explored the effects of Cadmium (Cd) with different concentrations (0, 14.5, 29 and 58 mg·L^-1) and exposure time (12, 24, 48, 72 and 96 h) on intracellular calmodulin (CaM) levels, Ca²⁺-ATPase activities, and apoptosis using technologies of biochemistry and histoenzymology. The results showed that the CaM levels and Ca²⁺-ATPase activities in Cd-exposed crabs significantly increased compared to the control after Cd exposure for 12 h and 24 h, and it was suggested that the intracellular Ca²⁺ concentrations was altered. Furthermore, Caspase-3/9 activities were significantly enhanced since 48 h Cd exposure, which may be resulted from intracellular Ca²⁺ level increase. The role of Ca²⁺ signaling in hepatopancreatic apoptosis induced by Cd was further confirmed by the pretreatment with Ca²⁺ inhibitors (EGTA and LaCl₃), and it turned out that the pretreatment with Ca²⁺ inhibitor (EGTA and LaCl₃) for 4 h before 48 h Cd exposure could effectively inhibit Caspase-3/9 activities. Therefore, we concluded that Ca²⁺ played an important role in the initiation of apoptosis induced by Cd in the hepatopancreas of the freshwater crab S. henanense.