Protective effect of thyroid hormone on spinal cord injury neurons in rats / 中华创伤杂志

ABSTRACT

Objective To investigate the protective effect of thyroid hormone on spinal cord injury neurons and its molecular mechanism.Methods A DMEM culture medium with a volume fraction of 10％ fetal bovine serum was cultured with the dorsal ridge neurons of RN-dsc rats.The neurons were inoculated in the culture plate after the digestion of trypsin and treated differently as follows(1) control groupDMEM treatment with no drugs or serum;(2) H2O2 groupserum-free DMEMtreatment containing 100 μmol/L H2O2;(3) H2O2 + 10-6 mol/L triiodothyronine (T3) groupserumfree DMEM treatment containing 100 μnol/L H2O2 and 10-6mol/L T3;(4) H2O2 + 10-5 mol/L T3 groupserum-free DMEM treatment containing 100 μ mol/L H2O2 and 10-5 mol/L T3;(5) negativecontrol grouptransfection of negative control mimics with LipofectamineTM2000 reagent;(6) miR-210 grouptransfection of miR-210 mimics with LipofectamineTM 2000 reagent.Cell viability,apoptosis number,and expressions of nuclear factor E2 correlation factor 2 (Nrf-2) antioxidant pathway molecules and miR-210 were determined.After transfection of miR-210 mimics and negative control mimics,expressions of Nrf-2 antioxidant pathway molecules were determined.Results The cell proliferation activity and protein expressions of Nrf-2,antioxidant reaction elements (ARE),superoxide dismutase 2 (SOD2),and heme oxygenase (HO-1) in H2O2 group (0.39 ±0.06,0.52 ±0.08,0.31 ±0.08,0.25 ± 0.05,respectively) were significantly lower than those in control group (1.00 ± 0.15,1.00 ± 0.17,1.00 ± 0.13,1.00 ± 0.11,respectively) (P ＜ 0.05),while the apoptosis numbers and the expressions of miR-210 were significantly higher than those in control group (P ＜ 0.05).The cell proliferation activity and protein expressions of Nff-2,ARE,SOD2,HO-1 in H2O2 + 10-6mol/L T3 group and H2O2 +10-5 mol/L T3 group were significantly higher than those in the H2O2 group (P ＜ 0.05),while apoptosis numbers and expressions of miR-210 were significantly lower than those in H2O2 group (P ＜ 0.05).The cell proliferation activity and protein expressions of Nrf-2,ARE,SOD2,HO-1 in H2O2 + 10-5mol/L T3 group (0.88 ±0.14,0.84 ±0.12,0.72 ±0.09,0.69 ±0.09) were significantly higher than those in H2O2 + 10-6mol/L T3 group (0.73 ±0.09,0.71 ±0.08,0.58 ±0.09,0.52 ±0.08) (P＜0.05),while apoptosis numbers and expressions of miR-210 were significantly lower than those in H2O2 + 10-6mol/L T3 group.The protein expressions of Nrf-2,ARE,SOD2,and HO-1 in miR-210 group (0.37 ±0.06,0.24 ±0.05,0.45 ± 0.08,0.49 ± 0.07,respectively) were significantly lower than those in negative control group (1.00±0.13,1.00±0.19,1.00±0.15,1.00±0.14,respectively) (P＜0.05).Conclusion Thyroid hormone can inhibit the expression of Nrf-2 in oxidative stress injury process of neurons by inhibiting the expression of miR-210,and hence reduce the oxidative stress injury of spinal cord neurons.