Protective effect of tubuloside B on TNFalpha-induced apoptosis in neuronal cells.

AIM

To investigate the neuroprotective effect of tubuloside B, one of the phenylethanoids isolated from the stems of Cistanche salsa, on tumor necrosis factor-alpha (TNFalpha)-induced apoptosis in SH-SY5Y neuronal cells.

METHODS

Cell viability was analyzed using MTT assay. Apoptotic cells were detected using Hoechst33342 staining, and confirmed by DNA fragmentation and flow cytometric analysis. The activity of caspase-3 was measured with special assay kit. The concentration of free intracellular calcium was determined with the probe Indo-1 by spectrometer. The level of intracellular reactive oxygen species and the potential of mitochondrial membrane were determined by laser scanning confocal microscopy (LSCM) combined with fluorescence probe H2DCFDA or JC-1 respectively.

RESULTS

SH-SY5Y cells treated with TNFalpha 100 microg/L for 36 h showed typical morphological changes of apoptosis. DNA ladder could be observed by agarose gel electrophoresis. The highest percentage of apoptotic cells accumulated to 37.5 %. Following 36 h treatment with TNFalpha, accumulation of intracellular ROS and [Ca2+]i and decrease in mitochondrial membrane potential were observed, and caspase-3 activity increased by about five-fold compared with controls. However, pretreatment with tubuloside B (1, 10, or 100 mg/L) for 2 h attenuated the TNFalpha-mediated apoptosis. The antiapoptotic action of tubuloside B was partially dependent on an anti-oxidative stress effects, maintain of mitochondria function, decrease of concentration of free intracellular calcium and inhibition of caspase-3 activity.

CONCLUSION

Tubuloside B has the neuroprotective capacity to antagonize TNFalpha-induced apoptosis in SH-SY5Y cells and may be useful in treating some neurodegenerative diseases.