Objective To investigate the injury of mitochondria of human liver cells L-02 caused by copper.
Methods The function of mitochondrion was determined by MTT assay. Mitochondrial ultrastructure was observed under transmission electron microscope. Rhodamine123(Rh123)and propidium iodide(PI)combining with flow cytometer were used to detect the changes of mitochondrial membrane potential(MMP)and cell apoptosis. Cytochrome C(CtyC)released from mitochondrion to endochylema was observed by immunocytochemistry.
Results Copper inhibited the function of mitochondrion in a concentration and time dependent manner. Different extent injuries of the mitochondrial ultrastructure were observed under transmission electron microscope. The results of flow cytometer detection indicated fluorescence intensity of Rh123 decreased from 93.60& #177;18.12(control group)to 59.94& #177;13.55(200μmol/L group), i.e. mitochondrial membrane potentia(l MMP)decreased in a dose dependent manner (P < 0.05, P < 0.01). The rate of cell apoptosis increased from 2.73%(control group)to 17.07%(200 μmol/L group)(P < 0.05, P < 0.01). With time extension, Rh123 fluorescence intensity degraded from 93.60& #177;18.12(control group)to 55.74& #177;15.45(24 h group), i.e. mitochondrial membrane potential(MMP)degraded in a time dependent manner(P < 0.05, P < 0.01). The rate of cell apoptosis increased from 2.73%(control group)to 20.45%(24 h group)(P < 0.05, P < 0.01). Immunocytochemistry results showed Cty C releasing from mitochondrion to endochylema, and the quantity increased in a concentration and time dependent manner.
Conclusion Copper could induce damage to mitochondria of human liver cell L-02 and make the MMP reduction and Cty C releasing from mitochondria to endochylema. The structure and function of mitochondria were destroyed. So cells were damaged even caused apoptosis.
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