| Summary: | 碩士 === 中山醫學大學 === 生物化學研究所 === 92 === Abstract
Mercury, one of the heavy metals, severely pollutes the environment in the present. It exists and cycles in three forms, mercury, inorganic mercury and organic mercury. In the present studies, it has been established that methyl-mercury and mercuric chloride have different levels of cytotoxicity effects depends on the cell lines, and the mode of cell death varies with different mechanisms stimulated by different compounds. The cinnabar is Chinese medicine, which contains mercury sulfur by chemical analysis and is commonly prescribed in pediatrics. In this experiment, we put mercury sulfur in the first place, and mercuric chloride or methyl-mercury in the second place. We attempted to use three mercurial compounds separately to stimulate human leukemia cell line (HL-60) and observe individually of cell damage . At first, we use MTT and DAPI fluorescence stain in order to observe how mercury sulfur, mercuric chloride and methyl-mercury affect the growth and differentiation of HL-60 by its dose-dependent toxicity. In addition, the PI stain and Annexin V/ PI double stain determine the characteristic in apoptosis by flow cytometry. We find mercury sulfur, mercuric chloride and methyl-mercury would cause different degree of apoptosis. In order to study the apoptotic mechanism caused by the mercurial compound, MBCL is used to determine the decrease of intracellular GSH , GSH is vital antioxidant and anti- metallotoxicity in the cell. And it was demonstrated that the decrease of GSH is related to the production of intracellular ROS. Therefore, we use H2DCFDA fluorescence stain and find out that HgS induce intracellular free radical (H2O2) accumulation. Rhodamine 123 dye is used to observe the changes of mitochondrial membrane potential. We find that mercurial compound would induce the depolarization of mitochondrial potential, while GSH plays an important role in this process. Conclude all the results above, we find that HgS would stimulate HL-60 apoptosis through the decrease of GSH and the ROS starts to accumulate in the cell . ROS would cause mitochondrial membrane potential disorder, and finally leads to the cell death.As2O3 was used to treat acute promyelocytic leukemia, however, this discovery provides a new direction for this treatment.
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