| Summary: | 碩士 === 國防醫學院 === 海底醫學研究所 === 93 === Amphetamine and its derivative methamphetamine (METH) are known to cause cell death both in vitro and in vivo. Nevertheless, the molecular and cellular mechanism of METH-induced neurotoxicity remains for further clarification. It is widely accepted that the cleavage of the caspase family of proteases is fundamental to the apoptotic process. In present study, we examined whether the mitochondrial-dependent apoptotic process is involved in METH-induced neurotoxicity in nondopaminergic rat primary cortical cells and dopaminergic PC12 cell (pheochromocytoma), respectively. The immunocytochemistry and flow cytometry techniques were used in this study. Our results demonstrated that METH induced apoptosis both in primary cortical culture and PC12 cell for 48 hrs. Treatment with METH also damaged neurons and astrocytes in the primary cortical culture. We further showed that METH dose-dependently decreased mitochondrial membrane potential (18 hrs). Ruthenium red, an inhibitor of mitochondrial Ca2+ uniporter, significantly inhibited METH-induced apoptosis. Both Ac-DEVD-CMK (a caspase-3 inhibitor) and 3-aminobenzamide (a PARP inhibitor) markedly attenuated the apoptosis produced by METH in cortical culture. In addition, METH increased superoxide production for 6 hrs, and the apoptotic cell death induced by METH can be prevented by superoxide dismutase (SOD)/catalase (CAT) pretreatment in cortical cells, whereas SOD/CAT did not restore mitochondrial membrane potential. Thioredoxin (Trx) is a redox-active protein which plays a neuroprotective role against oxidative stress. In this study, we evaluated the possible protective effects of Trx against METH-induced neurotoxicity. We found that Trx did not protect against METH-induced neurotoxicity. In summary, our studies show that the mitochondrial-dependent apoptotic pathway at least in part plays an important role in both primary cortical and PC12 cells after METH challenge.
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