ABSTRACT
Objective To observe the effect of HIF-1a/iNOS signaling pathway on myocardial ischemia-reperfusion injury in rat heart transplantation and the protective mechanism of N-acetylcysteine (NAC) on donor heart after cardiac transplantation in rats.Methods Eighty healthy male Lewis rats were randomly divided into 3 groups,the control group (0.3 ml saline was infused via inferior vena cava 30 min before donor harvest or implantation),NAC donor pretreatment group [NAC (30 mg/kg.w) was injected into the vena cava of donor rat 30 min defore donor harvest],and the NAC receptor pretreatment group (NAC 300 mg/kg.w was injected into the vena cava of the recipient rats 30 min before transplantation.The 30 min was injected into the vena cava of the recipient rats).A transplant model was established and the graft was obtained after 24 h transplantation.The expression of iNOS,HIF-1a and mRNA in cardiac muscle tissue was detected by immunohistochemistry and Real time-PCR.Results HIF-1a protein expression in graft myocardial tissue was significantly lower in NAC donor pretreatment and recipient pretreatment group compared with control group (P ＜0.05),the differences were statistically significant (2.72±0.17 vs.2.24±0.23 vs.3.14.±0.16,F=56.26,P =0.000).The iNOS protein expression in NAC donor pretreatment group,and NAC recipient pretreatment group were lower than that in the control group (1.52±0.18 vs.1.61±0.19 vs.3.30±0.18,F=232.345,P =0.000),the differences were statistically significant (P ＜ 0.05).24 h after transplantation,the differences in graft myocardial tissue HIF-1a and iNOS mRNA among the three groups were statistically significant (F=7.467,16.490,P=0.003,0.000).The expression of iNOS mRNA in the NAC receptor pretreatment group was significantly lower than that in the control group (P＜0.05).Conclusion HIF-1a/iNOS signaling pathway can regulate ischemia reperfusion injury in rat heart transplantation,and the protective effect of NAC on donor heart maybe mediated via this pathway.
ABSTRACT
MicroRNAs are a class of small noncoding RNAs that function as critical gene regulators through targeting mRNAs for translational repression or degradation. In this study, we showed that the miR-133b expression level was decreased while the Sirt1 mRNA expression level was increased in osteosarcoma tissue and cell lines. A low expression of miR-133b was significantly associated with tumor size, distant metastasis, and advanced clinical stage. In addition, osteosarcoma patients with a low miR-133b expression showed a worse prognosis when compared to those with a high level of miR-133b expression. Thus, we identified Sirt1 as a novel direct target of miR-133b. Overexpression of miR-133b suppressed Sirt1 expression and attenuated cell proliferation and invasion. Forced expression of Sirt1 could partly rescue the inhibitory effect of miR-133b in osteosarcoma cells. Our finding also suggested that the inhibitory effects of the miR-133b/Sirt1 axis on osteosarcoma progression were involved in the Wnt/ß-catenin pathway. Taken together, these findings will shed light on the role and mechanism of miR-133b in regulating osteosarcoma cell growth via the miR-133b/Sirt1 axis, and miR-133b may serve as a potential therapeutic target in osteosarcoma in the future.
