Figures & data
Figure 1. HBO therapy enhanced the decreased expression and activity of spinal cord SIRT1 induced by traumatic SCI. (A) The locomotor dysfunction was significantly improved after traumatic SCI rats were applied with series HBO therapy (n = 12/per group). (B) The protein level of spinal cord SIRT1 began to reduce at 8 h (1/3 day) and lasted at least at day 14 after the SCI injury established (n = 4/per group). (C–E) HBO treatment for consecutive 7 days significantly enhanced the decreased protein, mRNA and activity of SIRT1 in spinal cord (n = 5/per group). *p<0.05, **p<0.01, ***p<0.001 compared with sham group, #p<0.05, ##p<0.01 compared with SCI group.
Figure 2. Administration of SIRT1 antagonist EX-527 reversed the beneficial effects of HBO on locomotor recovery, whereas the SIRT1 agonist SRT1720 had synergic effects on the motor function with HBO therapy. (A-B) The SCI injury rats were applicated with both HBO and EX-527 (i.p.) for continuous 7 days (started at 8h postinjury) got the worse BBB scores compared with those with only administration of HBO and vehicle therapy, while the injury rats treated by HBO and intraperitoneal injection SRT1720 had the higher BBB scores versus those with only administration of HBO and vehicle therapy (n = 12 per group). (C-D) The EX-527 inhibited the enhanced activity of SIRT1 induced by HBO treatment, while SRT1720 increased effects of HBO therapy on the activity of SIRT1(n = 5 per group). *p < 0.05, **p < 0.01compared with SCI + vehicle + HBO group.
Figure 3. SIRT1 was implicated in the inflammatory cascade induced by traumatic SCI in rats. (A)The enhanced acetylation of NF-κB in SCI rats was remarkably inhibited by HBO treatment (n = 4/per group). (B)The increase of pro-inflammatory cytokines TNF-α, IL-6 and IL-1β and decrease of anti-inflammatory cytokine IL-10 in spinal cord of SCI model rats was revered after the SCI rats was administrated with HBO (n = 5/per group). (C) The effects of HBO treatment on TNF-α, IL-6, IL-1β and IL-10 was blocked by SIRT1 antagonist EX-527 (n = 5/per group). (D) Both application of SIRT1 agonist SRT1720 and HBO promoted the effects of HBO in TNF-α, IL-1β and IL-10 but not IL-6 (n = 5/per group). ***p<0.001 compared with sham group, #p<0.05, ##p<0.01 compared with SCI group, $$p<0.01 compared with SCI + vehicle + HBO group. SCI + V(SCI + vehicle), SCI + V + H (SCI + vehicle + HBO), SCI + E + H(SCI + EX-527 + HBO), SCI + S + H (SCI + SRT1720 + HBO).
Figure 4. HBO modulated the caspase family in a SIRT1-depentent manner. (A) The increase of expression of caspase 1, caspase 3, caspase 8 but not that of caspase 12 in SCI rats was dramatically alleviated following the HBO treatment (n = 4/per group). (B) After application of HBO and SIRT1 antagonist EX-527, the decreased caspase 1, caspase 3 and caspase 8 induced by HBO treatment was reversed (n = 5/per group). (C) The effects of HBO on the increased expression of caspase 3 and caspase 8 was enhanced following intraperitoneal injection of SIRT1 agonist (n = 5/per group). **p<0.01, ***p<0.001 compared with sham group, #p<0.05, $p<0.05 compared with SCI + vehicle + HBO group. SCI + V(SCI + vehicle), SCI + V + H (SCI + vehicle + HBO), SCI + E + H(SCI + EX-527 + HBO), SCI + S + H (SCI + SRT1720 + HBO).
Figure 5. Induction of autophagy in spinal cord of the injury rats was enhanced following HBO treatment. (A–C) The increased expression of autophagy-related protein ATG-5, Beclin-1, LC-II following the injury was enhanced (n = 5 per/group). (D) The decreased expression of p62 was induced by SCI injury and boosted by HBO treatment (n = 5 per/group). *p<0.05,**p<0.01 compared with sham group, #p<0.05 compared with SCI group.
Figure 6. The enhanced autophagy-related protein by HBO treatment was reduced after administration of EX-527. (A-C) Intraperitoneal injection of SIRT1 antagonist EX-527 abolished the increased expression of pro-autophagy formation-related protein (ATG-5, beclin-1, and LC3-2) in SCI rats following the series HBO therapy, (D) while the level of autophagy substrate p62 was upregulated by HBO (n = 5/per group). **p<0.01, ***p<0.001 compared with SCI + vehicle + HBO group.
Availability of data and material
The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.