The effect of lentivirus-mediated interleukin-1β siRNA on motor function in spinal cord contused rats

English Keywords:Spinal cord injury  Interleukin-1β  Synuclein gamma  Motor function  Rat

English Abstract:

  【Abstract】 Objectives: To observe the effect of interleukin-1β(IL-1β) small interfering RNA(siRNA) on motor function in rats after spinal cord contusion(SCC), and to investigate the corresponding mechanism. Methods: A total of 98 female SD rats was randomly divided into four groups: Sham group, SCC group, Vector group and IL-1β SH group. Rats in IL-1β SH group and Vector group were locally injected with IL-1β siRNA or vector in spinal cord at 48 hours before surgery. The vertebra resection was only performed in Sham group and the T10 contusion was prepared in other three groups. Basso Beattie & Bresnahan(BBB) score was recorded for five rats in each group at the day of surgery and 1d, 3d, 5d, 7d and 14d after surgery. In Sham group, rats were sacrificed at 28d after surgery, and the relative expression levels of IL-1β and synuclein gamma(SNCG) mRNA were detected by real-time fluorescence quantitative polymerase chain reaction(qRT-PCR). In SCC group, the relative expression levels of IL-1β and SNCG mRNA were detected at 6h, 12h, 1d, 3d, 5d, 7d and 14d after SCC. In Vector group and IL-1β SH group, the relative expression level of SNCG mRNA was detected at 7d after surgery, and the contused spinal cord was also perfused and fixed at 3d, 7d and 28d after surgery. Immunohistochemistry(IHC) was used to observe the SNCG immune-positive cells. The cells were then counted, and the average integrated optical density(IOD) values were determined. GeneMANIA analyzed the theoretical relationship between IL-1β and SNCG. Results: The BBB score in Sham group was always 21 at each time point. After SCC, the score of SCC group were significantly lower than that of Sham group(P<0.05). The score of IL-1β SH group was significantly higher than that of Vector group at 3d, 5d, 7d and 14d after SCC(P<0.05). The expression of IL-1β mRNA in SCC group was significantly more up-regulated than that in Sham group at 6h, 12h and 7d after surgery respectively(P<0.05), while the expression of SNCG mRNA at each time point was significantly more down-regulated than that in Sham group(P<0.05). The level of SNCG mRNA in IL-1β SH group was significantly higher than that in Vector group at 7d after surgery(P<0.05). In IL-1β SH group, SNCG immunoreactive cells and IOD values in the anterior horn of injured spinal cord were significantly better than those in Vector group at 3d, 7d and 28d after surgery(P<0.05). The subcellular localization between IL-1β and SNCG through Cfd was predicted by GeneMANIA. Conclusions: IL-1β siRNA improves the hindlimb motor function in rats, and upregulated the expression of SNCG protein and mRNA, which may be related to regulation of neuronal plasticity and inhibition of mitochondrial apoptosis pathways.