Estrogen receptor expression in lumbar intervertebral disc of the elderly: gender- and degeneration degree-related variations.
OBJECTIVE
Sexual dimorphism does occur in intervertebral disc (IVD) degeneration. The involvement of estrogen on IVD health has been well reported in recent years. The estrogen receptors (ER) are the main mediators of estrogen action. ER might play specific roles in the sexual variations of the IVD degeneration.


METHODS
Thirty-six elderly patients with lumbar disc degeneration were selected and graded using Pfirrmann's system based on MRI images. Differences of ERα and ERβ immunoreactivity staining in nucleus pulposus of each sex and degeneration degree were recorded and compared.


RESULTS
Both cytoplasmic and nuclear staining of ERα and ERβ immunoreactivity were observed in the nucleus pulposus cells. ERα and ERβ expression significantly decreased along with the aggravation of IVD degeneration both in males and females. Expression of ERα and ERβ protein in nucleus pulposus of males was significantly higher than that of females.


CONCLUSIONS
Gender-specific expression of ER might play a part in sexual dimorphism of IVD degeneration. Gender and degeneration condition differences should be taken into account when the effects of estrogen on IVD metabolism are studied further.
Department of Orthopaedic Surgery, Ren Ji Hospital,School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Department of Anesthesiology, Rui Jin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Xiao-xing
XX
Song
Department of Orthopaedic Surgery, Ren Ji Hospital,School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Yong-juan
YJ
Yu
Department of Orthopaedic Surgery, Ren Ji Hospital,School of Medicine, Shanghai Jiao Tong University, Shanghai, China. Electronic address: xinfengli@126.com.
Xin-feng
XF
Li
Department of Orthopaedic Surgery, Ren Ji Hospital,School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Zu-de
ZD
Liu
Department of Anesthesiology, Rui Jin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China. Electronic address: littlestar77@126.com.
Bu-wei
BW
Yu
Department of Orthopaedic Surgery, Ren Ji Hospital,School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Zhen
Z
Guo
D000368:Aged; D047628:Estrogen Receptor alpha / Q000096:biosynthesis*; D047629:Estrogen Receptor beta / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000378:metabolism* / Q000601:surgery; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D012737:Sex Factors
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta
Degeneration; Estrogen receptor; Intervertebral disc; Nucleus pulposus