Naringin Targets NFKB1 to Alleviate Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury in PC12 Cells Via Modulating HIF-1α/AKT/mTOR-Signaling Pathway.

This study was designed to investigate the effect of naringin in oxygen-glucose deprivation/reoxygenation (OGD/R) model and its mechanism. The target gene of naringin and the enriched pathways of the gene were searched and identified using bioinformatics analysis. Then OGD/R model was built using PC12 cells, after which the cells were treated with different concentrations of naringin. Subsequently, cell proliferation and apoptosis were evaluated by cell counting kit-8 (CCK-8) and flow cytometry assays, respectively. Meanwhile, the expression of NFKB1 in PC12 cells underwent OGD/R-induced injury was detected by qRT-PCR, while apoptosis-related and pathway-related proteins were checked by Western blot. DCF-DA kit was utilized to measure the level of ROS. Our results revealed that NFKB1, which was upregulated in MACO rats and OGD/R-treated PC12 cells, was a target gene of naringin. Naringin could alleviate OGD/R-induced injury via promoting the proliferation, and repressing the apoptosis of PC12 cells through regulating the expression of NFKB1 and apoptosis-associated proteins and ROS level. Besides, the depletion of NFKB1 was positive to cell proliferation but negative to cell apoptosis. Moreover, the depletion of NFKB1 enhanced the influences of naringin on cell proliferation and apoptosis as well as the expression of apoptosis-related proteins and ROS level. Western blotting indicated that both naringin treatment and depletion of NFKB1 could increase the expression of HIF-1α, p-AKT, and p-mTOR compared with OGD/R group. What's more, treatment by naringin and si-NFKB1 together could significantly increase these effects. Nevertheless, the expression of AKT and mTOR among each group was almost not changed. In conclusion, naringin could prevent the OGD/R-induced injury in PC12 cells in vitro by targeting NFKB1 and regulating HIF-1α/AKT/mTOR-signaling pathway, which might provide novel ideas for the therapy of cerebral ischemia-reperfusion (I/R) injury.

Activation of Nrf2-ARE signal pathway in hippocampus of amygdala kindling rats.

Oxidative stress resulting from excessive free-radical release is likely implicated in the initiation and progression of epilepsy. Therefore, antioxidant therapies have received considerable attention in epilepsy treatment. It is well known that the transcription factor NF-E2-related factor (Nrf2) binds to antioxidant response element (ARE) to induce antioxidant and phase II detoxification enzymes under conditions of oxidative stress, which reduces oxidative stress and accumulation of toxic metabolites. However, whether Nrf2-ARE pathway is activated after seizure has not been studied. In the present study, Wistar rats were rapidly kindled in the amygdala. Twenty-four hours after the last seizure, the hippocampus of control, sham and kindled rats were examined for oxidative stress parameters (malondialdehyde and glutathione) by spectrophotometry, the expression of Nrf2, heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO1) were determined using immunohistochemistry, Western blot and real-time fluorescence quantitative polymerase chain reaction (PCR). The results showed that the kindled seizures induced oxidative stress, the expression of Nrf2, HO-1 and NQO1 at protein or gene levels significantly increased in hippocampus after seizure. According to these results, it could be postulated that Nrf2-ARE signal pathway was activated in the hippocampus after seizure.

Anticonvulsant effect of dexmedetomidine in a rat model of self-sustaining status epilepticus with prolonged amygdala stimulation.

Status epilepticus (SE), leading to 27 percent mortality in adult patients, becomes refractory to firstline intravenous diazepam, with prolonged seizure duration. The mechanism could be attributed to the declined inhibitory action of GABA; therefore, alternative medications acting on other targets are necessary. The aim of the present study was to examine whether DEX, a highly specific central α2-adrenoreceptor agonist, could show the anticonvulsant effect on self-sustaining SE (SSSE), and to explore the involved mechanisms. Five minutes after SSSE, which was induced in adult Wistar rats by constant amygdala stimulation for 25 min, DEX was injected intraperitoneally at two dosages (50/100 µg/kg). The number and cumulative time of repeated seizures were recorded; the levels of Glu/GABA and glutathione/malondialdehyde (GSH/MDA) in hippocampus tissue were detected. The results showed that DEX effectively decreased the number and cumulative time of repeated seizures, alleviated the levels of Glu and GSH/MDA in hippocampus tissue, but no effect was detected on the level of GABA, suggesting that DEX could be a potential agent for the treatment of SSSE, the possible mechanisms were antioxidation and inhibition of the Glu release.

Environmental enrichment restores cognitive deficits induced by prenatal maternal seizure.

Maternal seizure has adverse effects on brain histology as well as on learning and memory ability in progeny. An enriched environment (EE) is known to promote structural changes in the brain and improve cognitive and motor deficits following a variety of brain injuries. Whether EE treatment in early postnatal periods could restore cognitive impairment induced by prenatal maternal seizure is unknown. Adult female Sprague-Dawley rats were randomly separated into two groups and were injected intraperitoneally either saline or pentylenetetrazol (PTZ) for 30 days. Then the fully kindled rats and control animals were allowed to mate. PTZ administration was continued until delivery, while the control group received saline at the same time. After weaning at postnatal day 22, one-half of the male offspring in the control and in the prenatal maternal group were given the environmental enrichment treatment through all the experiments until they were tested. Morris water maze testing was performed at 8 weeks of age. Western blot and synaptic ultrastructure analysis were then performed. We found that EE treatment reversed spatial learning deficits induced by prenatal maternal seizure. An EE also reversed the changes in synaptic ultrastructure following prenatal maternal seizure. In addition, prenatal maternal seizure significantly decreased phosphorylation states of cAMP response element binding (CREB) in the hippocampus, whereas EE reversed this reduced expression. These findings suggest that EE treatment on early postnatal periods could be a potential therapy for improving cognitive deficits induced by prenatal maternal seizure.

Effects of epigallocatechin-3-gallate on pentylenetetrazole-induced kindling, cognitive impairment and oxidative stress in rats.

Cognitive dysfunction is commonly observed in epileptic patients. It has been shown that not only epilepsy but also antiepileptic drugs could induce cognitive impairment. Thus, there is an urgent need for drugs that can suppress seizures without causing cognitive deficit. Recent studies have shown that oxidative stress is involved in the pathophysiology of epilepsy, and many antioxidants have an antiepileptic property. Epigallocatechin-3-gallate (EGCG), a catechin polyphenols component, is found to be an effective antioxidant. The purpose of this study was to assess the effect of EGCG against seizures, seizure-induced oxidative stress and cognitive impairment in pentylenetetrazole-induced kindling. Male Sprague-Dawley rats were injected intraperitoneally with a dose of 35 mg/kg of pentylenetetrazole (PTZ) once every alternate day for 13 injections. EGCG was administered daily in two doses (25mg/kg and 50mg/kg) intraperitoneally along with alternate-day PTZ. Morris water maze test was carried out 24h after the last injection of PTZ, and the oxidative stress parameters (malondialdehyde and glutathione) were assessed after the completion of the behavioral test. The results showed that EGCG dose-dependently suppressed the progression of kindling. EGCG also ameliorated the cognitive impairment and oxidative stress induced by PTZ kindling. These observations suggest that EGCG may be a potential agent for the treatment of epilepsy as well as a preventive agent against cognitive impairment induced by seizure.

[Exogenous carbon monoxide protects against liver injury induced by ischemia/reperfusion of hind limbs in rats].

AIM: To investigate the protective effect of exogenous carbon monoxide (CO) on the liver injury induced by ischemia/reperfusion (I/R) of hind limbs in rats. METHODS: 100 SD rats were divided randomly into sham operated group (S), S+ CO group (SC), I/R group (I/R), I/ R+ CO group (RC). A rat model of ischemia in hind limbs and the reperfusion liver injury was established with the occlusion of the femoral arteries for 4 h and re-opening for 6 - 72 h, 10 d. The rats in SC and RC groups were exposed to air containing CO (the volume traction of CO: 0.05%) for 2 h before and after reperfusion or the corresponding control time point, while the other two groups were exposed to the routine air. The pathologic changes of liver tissue were morphologically observed by HE stain. Serum GPT activity was tested by Automatic Biochemical Analyzer. The percentage of apoptosis, expression levels of bax and bcl-2 protein in liver tissue were detected by Flow Cytometry. RESULTS: There was no difference between S and SC groups. Compared with SC group: (1) Pathological changes in liver tissue were significant in I/R and RC groups. (2) The serum GPT activity of I/R and RC groups was obviously increased. (3) In IR and RC groups, the percentage of apoptosis in liver tissue was all significantly increased. (4) The bax expression level was significantly increased. Compared RC group with I/R group: (1) Pathological change was slight. (2) The serum GPT activity was depressed. (3) The percentage of apoptosis and expression level of bax protein in liver tissue were depressed. (4) The expression level of bcl-2 protein in liver tissue was increased. CONCLUSION: Exogenous CO could attenuate liver tissue injury induced by limbs I/R in rats.