title: Low magnitude of tensile stress represses the inflammatory response at intervertebral disc in rats.
abstract: OBJECTIVE
  This study aims to determine if the involvement of tensile stress affects the expressions of inflammatory cytokines interleukin-17(IL-17), interleukin-1β (IL-1β), and inducible nitric oxide synthase (iNOS) at intervertebral discs in vivo.
  
  
  METHODS
  Sixty-four female Sprague-Dawley rats were randomly divided into four groups: sham, tail-suspended (TS), tail-suspended with needle puncture (TSNP), and single-needle puncture (SNP) groups. A tail-suspension device provides low magnitude of tensile stress (2.45 Newton (N)), and aseptic needle puncture on the tail disc induces inflammatory response. After 4 weeks, the treated discs were harvested for histologic analysis, quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Pathological examination demonstrated that compared to the sham group, the morphologies of nucleus pulposus (NP) and anulus fibrosus (AF) in TS, SNP, and TSNP groups displayed degenerative changes in varying degrees. Results from RT-qPCR showed that IL-17 and iNOS mRNA expression levels were significantly higher in both TSNP and SNP groups than those in the sham groups. Expression of IL-17 and iNOS are not significantly different between the sham and TS groups (P > 0.05). Compared with the SNP group, the mRNA expression of IL-17 and iNOS in the TSNP groups were markedly decreased (P < 0.05). The regulation of IL-1β and IL-17 detected by ELISA was coincident with the qRT-PCR results.
  
  
  CONCLUSIONS
  The results from this study suggested that relatively low magnitude tensile stress might play an essential role in the anti-inflammatory process and the relief of low-back pain (LBP).
authors.affiliation: Department of Orthopaedics, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin City, 300052, PR China. craborth@163.com.|Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin City, 300211, PR China. craborth@163.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Han
authors.affiliation: Department of Orthopaedics, Tianjin Medical University General Hospital, No.154 Anshan Road, Heping District, Tianjin City, 300052, PR China. orthtj@yahoo.com.|Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin City, 300211, PR China. orthtj@yahoo.com.
authors.forename: Xin-Long
authors.initials: XL
authors.lastname: Ma
authors.affiliation: Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin City, 300211, PR China. orthspinewang@163.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin City, 300211, PR China. mjx969@163.com.
authors.forename: Jian-Xiong
authors.initials: JX
authors.lastname: Ma
authors.affiliation: Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin City, 300211, PR China. tianpeng007@foxmail.com.
authors.forename: Peng
authors.initials: P
authors.lastname: Tian
authors.affiliation: Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin City, 300211, PR China. zangjch1983@163.com.
authors.forename: Jia-Cheng
authors.initials: JC
authors.lastname: Zang
authors.affiliation: Tianjin Hospital, No. 406 Jiefang South Road, Hexi District, Tianjin City, 300211, PR China. kjb1501@163.com.
authors.forename: Jing-Bo
authors.initials: JB
authors.lastname: Kong
authors.affiliation: Department of Anesthesiology, Tianjin First Central Hospital, No.24 Fukang Road, Nankai District, Tianjin City, 300192, PR China. lixiaodantj@163.com.
authors.forename: Xiao-Dan
authors.initials: XD
authors.lastname: Li
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D005260:Female; D019417:Hindlimb Suspension; D007249:Inflammation / Q000150:complications / Q000378:metabolism* / Q000517:prevention & control; D020381:Interleukin-17 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D007403:Intervertebral Disc / Q000378:metabolism* / Q000473:pathology; D017116:Low Back Pain / Q000209:etiology / Q000628:therapy*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical
chemical_list: D015415:Biomarkers; C000594089:IL1B protein, rat; D020381:Interleukin-17; D053583:Interleukin-1beta; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat