钙信号对镉诱导河南华溪蟹细胞凋亡的调控

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.

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

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.