Pinocembrin prevents glutamate-induced apoptosis in SH-SY5Y neuronal cells via decrease of bax/bcl-2 ratio.
Pinocembrin is the most abundant flavonoids in propolis, and has been proven to have antioxidant, antibacterial and anti-inflammatory property. To assess the protective effects of pinocembrin on neurons, SH-SY5Y neuronal cells were pretreated with pinocembrin for 2 h followed by co-treatment with glutamate (2 mM) for 12 h. Cell viability was determined by(3,4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide assay, and apoptosis was confirmed by cell morphology, capillary zone electrophoresis and flow cytometry assay. Cell morphology was evaluated with Hoechst33258/PI dye. Treatment with pinocembrin (10(-5), 10(-6), 10(-7) mol/l) increased cell viability dose-dependently, inhibited LDH release and attenuated apoptosis. Intracellular free [Ca(2+)] was increased after glutamate exposure, and this increase was attenuated in cells treated with pinocembrin. bax mRNA expression increased remarkably following glutamate exposure and pinocembrin treatment manifested a reduction effect. bcl-2 mRNA expression changes were not detected in groups with or without pinocembrin. Western blotting results indicated that pinocembrin treatment reduced the expression of Bax and had no effect on Bcl-2, thus decreased the Bax-Bcl-2 ratio, which is in consistent with the gene expression result. Pinocembrin could also down-regulate the expression of p53 protein, and inhibit the release of cytochrome c from mitochondria to cytosol. Thus we conclude that pinocembrin exerts its neuroprotective effects in glutamate injury model partly by inhibiting p53 expression, thus Bax-Bcl-2 ratio, and the release of cytochrome c.
Gao
Mei
M
Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
Zhang
Wen-Cui
WC
Liu
Qing-Shan
QS
Hu
Juan-Juan
JJ
Liu
Geng-Tao
GT
Du
Guan-Hua
GH
D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D044950:Flavanones / Q000008:administration & dosage / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D018698:Glutamic Acid / Q000633:toxicity; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000187:drug effects / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000187:drug effects* / Q000378:metabolism
D044950:Flavanones; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D018698:Glutamic Acid; C016063:pinocembrin; D007770:L-Lactate Dehydrogenase; D002118:Calcium