Effects Of Oxidative Stress On The Apoptosis Of Rat Nucleus Pulposus Cells

OBJECTIVE:To study the effects of hydrogen peroxide(H₂O₂) on rat nucleus pulposus cells growth inhibition and apoptosis and to learn the roles of mitogen activated protein kinases(MAPKs) in rat nucleus pulposus cells apoptosis.METHODS:The rat nucleus pulposus are obtained in aseptic condition.After enzyme digestion,isolation,purification,the rat nucleus pulposus cell are cultured and maintened.The hydrogen peroxide was used to induce oxidative stress.The primary cultured cells are then divided into five groups:the control,H₂O₂,H₂O₂+SB203580, H₂O₂+SP600125 and H₂O₂+SB203580+ SP600125.The expression and localization of Phospho-mitogen activated protein kinase(P-p38MAPK)and Phospho-c-Jun NH2-terminal Kinase(P-JNK) was investigated by immunohistochemistry and Western blotting.RT-PCR was used to detect the expression of collagen typeâ…¡.RESULTS:The expression of phosphorylation of P38MAPK and JNK were increased after treatment of H₂O₂,The expression of phosphorylation of P38MAPK or JNK was significantly inhibited with the pretreatment of SB203580 or SP600125 compared with the H₂O₂ group.Immunofluorescence analysis demonstrated that P-p38MAPK and P-JNK were expressed and distributed mainly in cytoplasmic and nuclear,however,there were no expression in the control.CONCLUSIONS:Oxidative stress is a potent growth inhibitor of rat nucleus pulposus cells and MAPKs,especially p38MAPK and JNK,are important components of oxidative stress-mediated cell death.