Pinocembrin prevents glutamate-induced apoptosis in SH-SY5Y neuronal cells via decrease of bax/ bcl-2 ratio

• Published in: European journal of pharmacology 2008-09, Vol.591 (1), p.73-79
• Main Authors: Gao, Mei, Zhang, Wen-cui, Liu, Qing-shan, Hu, Juan-juan, Liu, Geng-tao, Du, Guan-hua
• Format: Article
• Language: English
• Subjects: Apoptosis; Apoptosis - drug effects; Bax; Bcl-2; bcl-2-Associated X Protein - drug effects; bcl-2-Associated X Protein - metabolism; Calcium - metabolism; Cell Line, Tumor; Cell Survival - drug effects; Dose-Response Relationship, Drug; Flavanones - administration & dosage; Flavanones - pharmacology; Gene Expression Regulation - drug effects; Glutamate; Glutamic Acid - toxicity; Humans; L-Lactate Dehydrogenase - drug effects; L-Lactate Dehydrogenase - metabolism; Neuroblastoma - metabolism; p53; Pinocembrin; Proto-Oncogene Proteins c-bcl-2 - drug effects; Proto-Oncogene Proteins c-bcl-2 - metabolism; RNA, Messenger - drug effects; RNA, Messenger - metabolism; Tumor Suppressor Protein p53 - drug effects; Tumor Suppressor Protein p53 - metabolism
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/j.ejphar.2008.06.071

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.