Effects of tension stress on the expression of inflammatory cytokines in intervertebral disc in rat / 中华骨科杂志

ABSTRACT

Objective To investigate the effect of tension stress on the changes of mRNA expression of interleukin-17B (IL-17) and inducible nitric oxide synthase (iNOS) in rat discs.Methods Sixty-four female Sprague-Dawley rats were randomly divided into 4 groupssham (S),tail-suspended (TS),tail-suspended with needle puncture (TSNP) and single needle puncture (SNP) groups.Tail-suspension device made rats of TS group and TSNP group hindlimb suspended,which exerted tension force on the coccygeal vertebrae disc;and aseptic needle puncture on the tail disc between the seventh and eighth coccygeal vertebrae (Co7/Co8)of TSNP,SNP group induced the inflammatory environment.The discs were harvested 4 weeks later.Measurements included gross observation,histological observation and real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR) analysis.Results Gross and histological examination found that varying degrees of degenerative changes in the annulus and nucleus in TS,SNP and TSNP groups,but not in the S group.RT-qPCR results showed that the mRNA of IL-17B and iNOS were significantly higher in the TSNP and SNP groups than that in the S group.The values of 2-△△Q were 12.99 and 8.12 in TSNP groups,and the 2-△△Q values of SNP group demonstrated 22.49 and 14.98 compared to S groups.Sole application of tension stress brought by the tail-suspension slightly enhanced the expression of IL-17B and iNOS,the values of 2-△△Q were 1.22 and 1.49,which didn't reach a statistically significant change.Compared with SNP group,the mRNA expression of IL-17B and iNOS in TSNP groups were shapely decreased,the values of 2-△△Q were-9.50 and -6.86 respectively.Conclusion Relatively low magnitude tension stress might play a key role in anti-inflammatory process and the relief of discogenic pain.