Recent studies have shown 5-hydroxymethyl-2-furfural (5-HMF) has favorable biological effects, and its neuroprotection in a variety of neurological diseases has been noted. Our previous study showed that treatment of 5-HMF led to protection against permanent global cerebral ischemia. However, the underlying mechanisms in cerebral ischemic injury are not fully understood. This study was conducted to investigate the neuroprotective effect of 5-HMF and elucidate the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway mechanism in the striatum after transient global cerebral ischemia. C57BL/6 mice were subjected to bilateral common carotid artery occlusion for 20 min and sacrificed 24 h after reperfusion. 5-HMF (12 mg/kg) or an equal volume of vehicle was intraperitoneally injected 30 min before ischemia and 5 min after the onset of reperfusion. At 24 h after reperfusion, neurological function was evaluated by neurological disability status scale, locomotor activity test and inclined beam walking test. Histological injury of the striatum was observed by cresyl violet staining and terminal deoxynucleotidyl transferase (TdT)-mediated dNTP nick end labeling (TUNEL) staining. Oxidative stress was evaluated by the carbonyl groups introduced into proteins, and malondialdehyde (MDA) levels. An enzyme-linked immunosorbent assay (ELISA)-based measurement was used to detect Nrf2 DNA binding activity. Nrf2 and its downstream ARE pathway protein expression such as heme oxygenase-1, NAD (P)H:quinone oxidoreductase 1, glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modulatory subunit were detected by western blot. Our results showed that 5-HMF treatment significantly ameliorated neurological deficits, reduced brain water content, attenuated striatum neuronal damage, decreased the carbonyl groups and MDA levels, and activated Nrf2/ARE signaling pathway. Taken together, these results demonstrated that 5-HMF exerted significant antioxidant and neuroprotective effects following transient cerebral ischemia, possibly through the activation of the Nrf2/ARE signaling pathway.

Abstract. Tumor necrosis factor-alpha (TNF-α) has been used as an effective treatment for Hepatocellular Carcinoma, however, inducing tumor cell apoptosis by TNF-α alone is still unsatisfactory. RhoA is highly expressed in hepatocarcinoma cells and can be activated by TNF-α. The activation of RhoA directly leads to a poor prognosis of HCC. Therefore, we propose to investigate the therapeutic effect of TNF-α together with RhoA siRNA. RhoA inhibition was accomplished by constructing a recombinant adenovirus that can efficiently express RhoA siRNA in HepG2 cells. The recombinant adenovirus AdshRNA-RhoA and AdU6-control were generated by adenovirus-mediated siRNA expression system. The inhibition effects were detected by RT-PCR in addition to immunoblot to quantify the decreased levels of RhoA expression, and the therapeutic effect for HCC was demonstrated by the proliferation and apoptosis ratios of HepG2 cells. The inhibition effects of RhoA by AdshRNA-RhoA were significant at both mRNA and protein levels: the transcription of RhoA mRNA decreased by 74.46%, and the expression of protein decreased by 76.48%. The proliferation rate of HepG2 cells detected by MTT showed that a treatment of AdshRNA-RhoA and TNF-α together could strengthen the suppression ability of TNF-α to HepG2 cells, resulting in approximately 14.2% more than those treated with only TNF-α. FCA and TUNEL assays results revealed that the combined treatment can induce apoptosis in approximately 52.14%-65% of the HepG2 cells, whereas this ratio in the TNF-α-alone group was only 21.91%-32%. Our results showed that AdshRNA-RhoA can efficiently enhance the TNF-α-induced apoptosis of hepatocarcinoma cells. This method might be a useful therapeutic route in HCC and other tumors.

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