Effect of CsA on mitochondria stress after microperfusing glutamate and calcium into tree shrews' hippocampus / 中国病理生理杂志

ABSTRACT

AIM: To observe the changes of glutamate and calcium within the hippocampal microenvironment in mitochondrial stress.METHODS: A lateral hippocampus was microperfused with glutamate and calcium chloride solution by a kind of single-pumped push-pull perfusion system in Tree Shrews.At 24 h,the expression of cytochrome C(Cyt C)was observed by immunochemistry.Also,the hippocampus was removed,then mitochondria and cytoplasmic fragment were divided by low temperature centrifugation and the distribution of cytochrome C was assessed through Western blotting.The relative amounts of caspase-3 and caspase-9 mRNA were evaluated by real time fluorescence polymerase chain reaction.In the treated group,cyclosporin A(CsA,40 mg/kg) was intravascularly injected at 6 h after perfusion of glutamate-calcium chloride solutions into the hippocampus and inspected the above-mentioned items at 24 h.RESULTS: In the glutamate-calcium group,compared with the control group,cytochrome C immunoreactivity increased and the content of hippocampal mitochondrial cytochrome C decreased.Also,the cytochrome C was detected in cytosol.Cyclosporin A treatment at 6 h after microperfusion,the cytochrome C expression weakened and no Cyt C in cytosol fraction was observed.By real time PCR,in relation to the control group,the caspase-3 and caspase-9 mRNA was higher in the glutamate-calcium group.Cyclosporin A treatment cut down both caspase-3 and caspase-9 mRNA contents.CONCLUSION: The accumulation of glutamate and calcium may promote Cyt C release,caspase cascade activation and the mitochondrial stress.The neuroprotection of CsA may results from uniquely inhibiting the mitochondrial permeability transition pore,and preventing Cyt C release and caspase activation.