Cyclophilin A can protect neurons against oxidative stress.OBJECTIVE:
To investigate the effect of cyclophilin A on Bcl–2 and Bax protein expression in pheochromocytoma (PC12) cells treated with beta-amyloid fragment 25–35 (A β 25–35), and to verify the protection pathway of cyclophilin A.DESIGN, TIME AND SETTING:
The initial experiment was performed at the Laboratory of Department of Neurology, First Clinical College, China Medical University from November 2006 to July 2007.MATERIALS:
PC12 cells were cultured at the Cell Center of Peking Union Medical College. A β 25–35 (Sigma, USA), antibodies of Bcl–2 and Bax (Wuhan Boster, China), and recombinant human cyclophilin A (Biomol, USA) were used in this study.METHODS:
PC12 cells were divided into three groups. Cells in the control group were incubated in culture medium. Cells in the A β 25–35 injury group were incubated in medium containing a final concentration of 10 μ mol/L of A β 25–35. Cells in the cyclophilin A group were incubated in medium containing a final concentration of 10 nmol/L of cyclophilin A for 30 minutes, and then treated with 10 μ mol/L A β 25–35.MAIN OUTCOME MEASURES:
After 24 hours of culture, immunohistochemistry was used to detect Bcl–2 and Bax expression in PC12 cells. Annexin-V flow cytometry was employed to measure the apoptosis rate of PC12 cells. The MTT method was applied to examine the survival rate of PC12 cells.RESULTS:
Bcl–2 expression decreased, whereas Bax expression increased in PC12 cells treated with A β 25–35 (t = 2.277, 5.957, P < 0.05). However, in PC12 cells treated with A β 25–35 and cyclophilin A, Bcl–2 expression increased and Bax expression decreased (t = 4.497, 2.531, P < 0.05). The survival rate of PC12 cells significantly decreased and the apoptosis rate increased (t=8.509, 22.886, P < 0.05) following A β 25–35 treatment. Cyclophilin A enhanced the survival rate of PC12 cells to A β 25–35-induced apoptosis (t = 4.895, 10.042, P < 0.05).CONCLUSION:
Cyclophilin A can increase Bcl–2 expression and decrease Bax expression in PC12 cells treated with A β 25–35, which indicates that cyclophilin A has a protective effect on A β 25–35-induced injury to PC12 cells.