Effects of oxidative stress on the apoptosis of nucleus pulposus cells in rats

Hongtao LI; Dechun WANG; Jianwei WEI

ABSTRACT

BACKGROUND:

Apoptosis,which result in various reasons,plays an important role in intervertebral disc degeneration. One of important reasons for apoptosis is oxidative stress.

OBJECTIVE:

To investigate effects and mechanism of hydrogen-peroxide(H2O2) on nucleus pulposus cell injury induced by oxidative stress at intracellular signal transduction level in rats. DESIGN,TIME AND

SETTING:

A single sample observation was performed at the institute of Traumatology and Orthopaedics of Shandong Province from March to October in 2008. MATERIALSThe specific p38 mitogen-activated protein kinase(p38 MAPK) inhibitor SB203580,the specific JNK inhibitor SP600125 were purchased from Beyotime Institute of Biotechnology;Two 24-hour-old SD rats of SPF degree were purchased from Qingdao Institute for Drug Control.

METHODS:

The primary cultured nucleus pulposus cells were divided into four groupsthe H2O2 group,stimulated by H2O2 with concentrations of 0,50,100,200,400,and 800 ?mol/L;Control group;SB203580+H2O2 groupcells were preincubated with SB203580,and then were treated by stimulated by H2O2;SP600125+H2O2 group,cells were preincubated with SP600125,followed by stimulated by H2O2. MAIN OUTCOME

MEASURES:

The expression and cellular localization of P-p38MAPK and P-JNK was detected by immunohistochemistry,and the expression of total and phosphorylated SAPK/JNK,p38MAPK were measured by Western blotting.

RESULTS:

H2O2 could activate the activity of P38 and JNK. The expression of P38MAPK was significantly inhibited with the pretreatment of SB203580;however,the SP600125 could inhibit the expression of JNK. Immunofluorescence analysis demonstrated that P-p38MAPK and P-JNK were expressed and distributed mainly in cytoplasmic and nuclear exception of the control group.

CONCLUSIONS:

Apoptosis of rat nucleus pulposus cells are induced by oxidative stress via p38MAPK and JNK signal pathway.