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Int J Clin Exp Pathol 2013;6(8):1567-1573

Original Article
Expression of soluble Fas and soluble FasL in human nucleus pulposus cells

Zhen Sun, Zhong-Yuan Wan, Zhi-Heng Liu, Yun-Shan Guo, Jun-Bin Yin, Chun-Guang Duan, Yang Gao, Tao Li, Hai-Qiang Wang, Zhuo-Jing Luo

Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi’an, P. R. China; Department of Anatomy & K.K. Leung Brain
Research Center, Preclinical School of Medicine, Fourth Military Medical University, Xi’an, P. R. China

Received June 20, 2013; Accepted July 5, 2013; Epub July 15, 2013; Published August 1, 2013

Abstract: The study aimed for addressing the expression of soluble Fas (sFas) and soluble Fas Ligand (sFasL) in human nucleus pulposus
(NP) and its attendant relationship with disc degeneration. Human NP samples were collected from patients with disc degeneration and
cadavers as degenerate and normal groups, respectively. Subsequently, NP cells were cultured in monolayer. ELISA was performed to identify
the expression levels of sFas and sFasL in the supernatant of NP cell cultures in vitro. Quantitative real-time PCR was used to detect the
expression of sFas and sFasL in human NP cells in mRNA solution. The study comprised 12 degenerate and 8 normal cadaveric NP
samples. The concentration value of sFas in the supernatant was significantly higher from degenerate NP than that from normal NP at each
time point. In contrast, sFasL was significantly lower at each time point. Moreover, the expression of sFas and sFasL reached the peak at
various early stages of cell cultures and decreased thereafter. Furthermore, the mRNA level of Fas in degenerate NP cells was significantly
higher than that in normal cells; whereas FasL showed an opposite pattern. The study is the first addressing the expression of sFas and
sFasL in human NP cell cultures. Moreover, the expression of sFas and sFasL varies with culture time in vitro with different levels in
degenerate and normal settings. These findings indicate that sFas and sFasL might play a role in intervertebral disc degeneration.
(IJCEP1306017).

Keywords: Intervertebral disc, nucleus pulposus, soluble Fas, soluble FasL, immune privilege

Address correspondence to: Hai-Qiang Wang and Zhuo-Jing Luo, Institute of Orthopaedics, Xijing Hospital, 15 Changle Western Road, Fourth
Military Medical University, Xi’an, P. R. China, 710032, USA. Phone: +86-298-477-5285; Fax: +86-298-477-5285; E-mail: hqwang@fmmu.edu.cn
and zjluo@fmmu.edu.cn