Effects of harpagide on nerve cell and caspase-independent apoptotic signaling pathway in MCAO mice / 中国药理学通报

ABSTRACT

Aim To study the effects of harpagide on hippocampal neurons, mitochondrial function and caspase-independent apoptosis pathway after cerebral ischemia in mice. Methods The middle cerebral ar-tery occlusion (MCAO ) was employed to establish MCAO model. After that,the mice were given harp-agide (4,8,12 mg·kg - 1 )and edaravone (3. 2 mg ·kg - 1 )by tail vein injection after MCAO immediate-ly,and the model and control mice were given equal a-mounts of saline by the same way. After MCAO for 6 h,the apoptosis rate of hippocampal neuron and the mitochondrial membrane potential (MMP)of MCAO mice were detected by flow cytometry. We observed the clarity of inner and outer membrane of the hipp-ocampal neuronal mitochondrial,the integrity of the mitochondrial cristae,the changes of matrix electron density of mitochondria,and mitochondria swelling by transmission electron microscopy. Western blot was employed to determine the expression of apoptosis in-duced factor (AIF)and endonuclease G (Endo G)in mitochondrion and pro-caspase-3 in endochylema. qPCR was employed to determine the expression of AIF and Endo G. Results Compared with control group, the apoptosis rate of hippocampal neuron of MCAO mice significantly increased(P < 0. 01),the MMP of hippocampal neuron significantly decreased and the mi-tochondrial ultrastructure of cerebral ischemic area was severely damaged, loosely arranged and obviously swollen;the expression of AIF and Endo G in mito-chondria of cerebral tissue of MCAO mice significantly decreased,and the releases of AIF and Endo G signifi-cantly increased(P < 0. 01);the expressions of AIF, Endo G mRNA were evidently up-regulated (P <0. 01). Compared with model group,each dose of harpagide could significantly decrease the apoptosis rate of hippocampal neurons of mice brain (P < 0 . 05 ,P < 0. 01);MMP markedly increased in hippocampal nerve cells(P < 0. 01);the ultrastructure of neuronal mitochondria was obviously improved. Compared with model group,harpagide (8,12 mg·kg - 1 )could sig-nificantly increase the expression of AIF and Endo G protein in mitochondria of mouse brain,and the release of mitochondrial AIF and Endo G protein decreased(P< 0. 05,P < 0. 01);harpagide (4 mg·kg - 1 )could significantly increase the expression of Endo G protein in mitochondria of mouse brain,and the release of En-do G protein markedly decreased (P < 0. 05);harp-agide (8,12 mg·kg - 1 )could significantly decrease the expression of AIF and Endo G mRNA in hippocam-pus of mice(P < 0. 05,P < 0. 01). Conclusion The protective effect of harpagide on MCAO may be related to the protective effects on cerebral nerve cells,the ac-tivity of the mitochondria and the inhibition of caspase-independent apoptotic signaling pathways.