Study Design. Both sequestrated nucleus pulposus (SNP) and the remaining nucleus pulposus (RNP) were studied from the discs of the same patient to evaluate apoptosis using immunohistochemical staining.
Objective. To compare apoptosis of the SNP and the RNP in the disc of the same patient.
Summary of Background Data. Many studies have been conducted on the natural history and apoptosis of the herniated nucleus pulposus; however, apoptosis of the remaining nucleus cells, after removal of the sequestrated disc, in the same patient, has not been reported.
Materials and Methods. Eight samples of SNP and RNP from the disc of the same patient were obtained. The TUNEL stain was performed to confirm the occurrence of apoptosis in disc cells. Immunohistochemistry staining and Western blot analysis were performed to determine the presence of proteins, including caspase-3,-8,-9, and Bid.
Results. TUNEL-positive chondrocytes were identified in all of the SNP and RNP samples; the apoptotic index was 5.8 ± 1.9% and 5.9 ± 1.2%, respectively (P = 0.60). Caspase-3,-8,-9, and Bid were expressed in the SNP and the RNP of the cytoplasm and the nucleus by the immunohistochemical staining. The expression of active caspase-3,-8,-9, and Bid in the RNP of the disc and the SNP was different in each patient.
Conclusion. The frequency of chondrocyte apoptosis in the SNP and the RNP was not different in the disc. The pathways involved in chondrocyte apoptosis of the SNP and the RNP differed among individuals and included intrinsic and/or extrinsic pathways.
This study evaluated apoptosis of the SNP and the RNP in the disc of patients. The apoptotic index for the SNP and RNP was 5.8 ± 1.9% and 5.9 ± 1.2%, respectively. The expression of active caspase-3,-8.-9 and Bid in the RNP and the SNP of the disc was different in each patient
From the Department of Orthopaedic Surgery, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
Address correspondence and reprint requests to Kee-Yong Ha, MD, 505 Ban Po-Dong, Seo Cho-Ku, Department of Orthopaedic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, 137–701, Korea; E-mail: firstname.lastname@example.org.
Acknowledgment date: September 25, 2009. Revise date: January 12, 2010. Accepted date: February 18, 2010.
The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.