Mechanism Of Apoptosis Induced By Cadmium

Cadmium can induce apoptosis in many kinds of cells. Studying the apoptosis induced by cadmium is necessary for us to cure lots of diseases caused by cadmium. This paper studied some aspects of the mechanism of apoptosis induced by cadmium:1 Disequilibrium of calcium homeostasis and apoptosis induced by cadmium in SD rat kidney cellsUnder the condition of 37 and 5% CO2, SD rat kidney cells was incubated in FD medium with different concentrations of cadmium and sodium selenite plus cadmium, then the apoptosis was detected by using acridine orange/ethidium bromide double fluorescent dye staining, and the free calcium concentration in cells was detected by using fluorescent indicator fluo-3 as the probe. The results showed that the different degree apoptosis in SD rat kidney cells was induced by different concentration of calcium. The result showed that the elevation the doses of cadmium cause an increase in rate of apoptotic and in concentration of the calcium ions in cytoplasm in a dose-dependent positive correlation. The results also showed that sodium selenite in low concentration can decrease the rate of apoptosis in SD rat kidney cells induced by cadmium. It is suggested that cadmium might cause apoptosis and disequilibrium of calcium homeostasis in SD rat kidney cells.2 Apoptosis triggered by disequilibrium of intracellular calcium homeostasis induced by cadmium in HEK293 cellsBy utilizing acridine orange/ethidium bromide double fluorescent dye staining to detect the apoptosis and by using MTT to detect the growth inhibition; fluorescent dye Fluo-3/AM and Fura-2/AM was used to test the change of intracellular free calcium; the effect of calcium on calcineurin was measured by a calcineurin test kit. The results showed that cadmium cause apoptosis and growth inhibition in HEK293 cells in a dose-dependent manner and that cadmium initiate a rapid release of Ca2+ form Ca2+ pool followed by the influx of the extracellular Ca2+. The result also revealed that some inhibitors of the signal of calcium prevented Cd-induced cells from apoptosis and that the activity of calcineurin was enhanced by cadmium. It is suggested that the disequilibrium of calcium homeostasis induced by cadmium plays an essential role inthe process of cadmium-induced apoptosis.3 Apoptosis caused by the release of cytochrome C induced by cadmium inHEK293 cellsThe variation of mitochondrial membrane potential and reactive oxygen species production were detected by fluorescent indicator Rhodaminel23 and DCFH-DA, respectively. The release of cytochrome C from mitochondria was tested by immunblot technique. The results showed that cadmium reduce the level of mitochondrial membrane potential and improve reactive oxygen species production in HEK293 cells. Meanwhile, cadmium induced the release of cytochrome C into cytoplasm. It is suggested that cadmium can induce the decrease of mitochondrial membrane potential, which caused the release of reactive oxygen species and cytochrome C, the process that causes apoptosis in HEK293 cells.