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Objective To investigate the role of miR-21 and p53 in hypoxic-ischemic injury of neural cells and to explore its mechanism. Methods The cultured mouse neuroblastoma cell line N2a was randomly divided into the miR-21 (20, 40, 60 nmol/L) transfection group, negative control group, and blank control group by using Lipo2000 liposome transfection method. Ischemia-reperfusion injury model was established by oxygen glucose deprivation and reperfusion. Ap-optotic index was measured by TUNEL staining, the expression of intracellular miR-21 and p53 mRNA was detected by real-time fluorescence quantitative PCR , and the expression of p53 protein was detected by Western blotting. Results Compared with blank control group and negative control group, the relative expression of miR-21 in the transfection group was higher (P<0.05) , and the relative expression of miR-21 was concentration-dependent (P< 0.05). The apoptotic index of miR-21 (60 nmol/L) transfection group was lower than that of negative control group and blank control group (P < 0.05). The expression of p53 in the cells transfected with miR-21 (40, 60 nmol/L) was lower than that in the negative control group and the blank control group (P < 0. 05) , and the higher the concentration, the lower the expression of p53 ( P <0. 05 ). Conclusion Overexpression of miR-21 can protect neurons from hypoxic-ischemic injury, which may be related to its negative regulation of p53 expression in N2a cells. [ABSTRACT FROM AUTHOR]

Objective To observe the effeet of the formula of Herba Erigerontis and Radix Paeoniae Rubra in oxygen-glueose deprivation/reoxygenation (OGD/R) on oxidative stress and nuclear factor-κB (NF-κB) signaling pathway of nerve cells (PC12 cells) after ischemia-reperfusion injury and to investigate its mechanism of protective effect. Methods The PC 12 cells were cultured and divided into the control group, model group and low-dose, medium-dose and high-dose formula groups. The models of ischemia-reperfusion injury in the model group and formula groups were established by OGD/R. Then the rats in the low-dose, medium-dose and high-dose formula groups were treated with 0. 31 . 0. 62, and 1. 25 mg/L formula of Herba Erigerontis and Radix Paeoniae Rubra, and all were intervened for 4 h. The control and model groups were treated with DMEM only. The activity of superoxide dismuta.se (SOD) and the level of malondialdehyde (MDA) in cell supernatant were detected by ELISA. The protein expression of NO synthase (iNOS), cyclooxygenase-2 (COX-2) and the related proteins (IκBcα. p-IκBcα and p65) of NF-κB signaling pathway was examined by Western blotting. Results Compared with the control group, the level of SOD was decreased, the level of MDA was increased in the model group (all P <0.01). Compared with the model group, the level of SOD was increased in the medium-dose and high-dose formula groups (P < 0.05 or P <0. 01). The level of MDA was decreased in all formula groups (P < 0. 05 or P < 0. 01). Compared with the control group, the protein expression of iNOS and COX-2 was decreased in the model group (all P <0. 01). Compared with the model group. the protein expression of iNOS and COX-2 was deereased in all formula groups (P <0. 05 or P <0. 01). Compared with the eontrol group, the value of p-IκBcα/IκBo in cytoplasm, and p65 in nucleus of the model group was increased (all P <0. 01). Compared with the model group. the value of p-IκBαand IκBcα in cytoplasm and p65 in nucleus of all formula groups (P <0. 05 or P <0. 01). Conclusions The formula has protective effect on PC12 cells after ischemia-reperfusion injury. The mechanism may be related to the reduction of intracellular oxidative stress response and inhibition of NF-kB pathway activation. [ABSTRACT FROM AUTHOR]

Objective To observe the protective effect of erythropoietin (EPO) on rats with hypoxic-ischemic brain injury (HIBD) and to explore its mechanism. Methods A total of 120 Wistar rats in 7-day-old were selected and randomly divided into three groups (n=40): sham operation group (control group), HIBD group and EPO treatment group. After HIBD model was established, EPO (5 000 IU/kg) was injected into rats of the EPO treatment group; while in the HIBD group, the equal volume normal saline was injected. Rats were killed at 6, 12, 24, 48 and 72 h, 8 rats at each time point per group. Then the expression levels of Fas/FasL mRNA and protein in the brain tissues were detected by real-time PCR and Western blotting, respectively. Results In HIBD group, Fas mRNA expression was observed at 6 h, increased rapidly and reached the peak at 12 h, then decreased after 24 h; in EPO treatment group, the expression of Fas mRNA was lower than that in HIBD group at each time point, and the difference was significant at time points of 12, 24 and 48 h (all P<0.05). Similarly, FasL mRNA was increased obviously from 6 h to 24 h, and reached the peak at 24 h, and then decreased gradually, the FasL mRNA level was significantly decreased in EPO treatment group as compared with that of the HIBD group at 6, 12, 24 and 48 h (all P<0.05). On the protein level, the Fas and FasL in the control group was very low; and there was a changing trend in the HIBD group, which rose first and then fell; the Fas protein expression at 24 and 48 h, and FasL protein expression at all the time points in the EPO treatment group was significantly decreased (all P<0.05). Conclusion EPO could alleviate the damage of HIBD on neurons in the brain tissue and have an effective protective effect, whose mechanism might be that the apoptosis of neuronal cells are inhibited through the down-regulation of Fas/FasL signal pathway in the HIBD brain tissues. [ABSTRACT FROM AUTHOR]