Status epilepticus: Using antioxidant agents as alternative therapies

Zingerone Targets Status Epilepticus by Blocking Hippocampal Neurodegeneration via Regulation of Redox Imbalance, Inflammation and Apoptosis

Epilepsy is an intricate neurological disease where the neurons are severely affected, leading to the mortality of millions worldwide. Status epilepticus (SE), induced by lithium chloride (LiCl) and pilocarpine, is the most accepted model for epilepsy. The current work aims to unravel the mechanisms underlying the anti-epileptic efficacy of zingerone (an active ingredient of ginger), which has beneficial pharmacological activities on seizure-induced behavioral, histological, neurochemical, and molecular patterns in mice. Zingerone restored cognitive function by diminishing seizure activity, escape latency, and subsequent hippocampal damage manifested in histology. Seizures are associated with local inflammation, redox imbalance, and neural loss, confirmed by the present study of SE, and was attenuated by zingerone treatment. Nuclear factor-kappa B and its downstream signaling molecules (TNF-α, IL-1β, IL-6, NO, MPO) were activated in the LiCl-and-pilocarpine-induced group leading to inflammatory signaling, which was substantially ameliorated by zingerone treatment. The intrinsic apoptotic process was triggered subsequent to SE, as demonstrated by augmentation of cleaved caspase-3, downregulation of Bcl-2. However, zingerone treatment downregulated caspase-3 and upregulated Bcl-2, increasing cell survival and decreasing hippocampal neural death, deciphering involvement of apoptosis in SE. Therefore, zingerone plays an essential role in neuroprotection, probably by precluding oxidative stress, inflammation, and obstructing the mitochondrial pathway of apoptosis.

LncRNA TUG1 inhibits neuronal apoptosis in status epilepticus rats via targeting the miR-421/mTOR axis

Status epilepticus (SE) induces apoptosis of hippocampal neurons. However, the underlying mechanism in SE is not fully understood. Recently, lncRNA TUG1 is reported as a significant mediator in neuronal development. In present study, we aimed to investigate whether lncRNA TUG1 induces apoptosis of hippocampal neurons in SE rat models. TUG1 expression in serum of normal volunteers and SE patients, SE rats and neurons with epileptiform discharge was detected. SE rat model was established and intervened with TUG1 to evaluate hippocampal neuronal apoptosis. The experiments in vitro were further performed in neurons with epileptiform discharge to verify the effects of TUG1 on neuronal apoptosis of SE rats. The downstream mechanism of TUG1 was predicted and verified. miR-421 was intervened to perform the rescue experiments. Levels of oxidative stress and inflammation-related factors and mTOR pathway-related proteins in SE rats and hippocampal neurons were detected. TUG1 was highly expressed in serum of SE patients, SE rats and neurons with epileptiform discharge. Inhibition of TUG1 relieved pathological injury, oxidative stress and inflammation and reduced neuronal apoptosis in SE rats, which were further verified in hippocampal neurons. TUG1 upregulated TIMP2 expression by targeting miR-421. Overexpressed miR-421 inhibited hippocampal neuronal apoptosis. TUG1 knockout inactivated the mTOR pathway via the miR-421/TIMP2 axis to relieve neuronal apoptosis, oxidative stress and inflammation in SE rats and hippocampal neurons. Taken together, these findings showed that downregulation of lncRNA TUG1 inhibited apoptosis of hippocampal neurons in SE rats, and attenuated oxidative stress and inflammation damage through regulating the miR-421/mTOR axis.

Taurine/Pilocarpine Interaction in the Malnourished Rat Brain: A Behavioral, Electrophysiological, and Immunohistochemical Analysis

This study aimed to evaluate the possible protective role of taurine on anxiety-like behavior, brain electrical activity and glial cell immunoreactivity in well-nourished and malnourished rats that were treated with a subconvulsing dose of pilocarpine. Newborn Wistar rats were subjected to normal or unfavorable lactation conditions, represented by the suckling of litters with 9 or 15 pups, resulting in well-nourished and malnourished animals, respectively. Each nutritional group was split into five subgroups that were treated from postnatal day (PND) 35 to 55 with 300 mg/kg/day of taurine + 45 mg/kg/day of pilocarpine (group T + P), taurine only (group T), pilocarpine only (group P), vehicle control (group V), or not treated control (group naïve; Nv). At PND56-58, the groups were subjected to the elevated plus-maze behavioral tests. Glycemia was measured on PND59. Between PND60 and PND65, the cortical spreading depression (CSD) was recorded in the cerebral cortex, and the levels of malondialdehyde and microglial and astrocyte immunoreactivity were evaluated in the cortex and hippocampus. Our data indicate that treatment with taurine and pilocarpine resulted in anxiolytic-like and anxiogenic behavior, respectively, and that nutritional deficiency modulated these effects. Both treatments decelerated CSD propagation and modulated GFAP- and Iba1-containing glial cells. Pilocarpine reduced body weight and glycemia, and administration of taurine was not able to attenuate the effects of pilocarpine. The molecular mechanisms underlying taurine action on behavioral and electrophysiological parameters in the normal and altered brain remain to be further explored.

Pilocarpine/ascorbic acid interaction in the immature brain: Electrophysiological and oxidative effects in well-nourished and malnourished rats

Ascorbic acid (AA) administration has been associated with neuroprotection against oxidative stress, although at high doses it can facilitate oxidation and acts like a proconvulsing drug. The pilocarpine-induced epilepsy model has been widely studied. However, less is known about the effects of sub-convulsive doses of pilocarpine on brain activity in immature animals under normal or deficient nutritional conditions. Herein, we investigated the effects of chronic pilocarpine administration in a sub-convulsive dose, with or without AA, on the excitability-related phenomenon denominated as cortical spreading depression (CSD) and levels of lipid peroxidation-induced malondialdehyde in well-nourished and malnourished rats. At postnatal days 7-28, rats received no gavage treatment (naïve group), saline (vehicle group), 45 mg/kg/d of pilocarpine and/or 120 mg/kg/d of AA. CSD propagation and malondialdehyde levels were analyzed at 34-40 days. The pilocarpine group presented with lower CSD velocities, while AA groups exhibited higher CSD velocities and augmented malondialdehyde levels compared with controls. The co-administration of AA partially antagonized the pilocarpine CSD effects, but did not revert it to control levels. Malnutrition increased CSD amplitude and velocity in comparison to the well-nourished condition. The electrocorticogram (ECoG) amplitude increased after CSD (ECoG potentiation) when compared with the baseline amplitude before CSD. However, no intergroup difference was observed in this CSD-related ECoG potentiation. The results support the hypothesis of a pilocarpine/ascorbic acid interaction in the immature rat brain and might help further the understanding of this interaction on neuronal electrical activity and oxidative stress.

Anticonvulsant activity of resveratrol-loaded liposomes in vivo

Resveratrol (3,5,4'-stilbenetriol), a natural polyphenol produced by various plants, has attracted attention over the past decade because of its multiple beneficial properties, including anti-inflammatory, anti-oxidant and chemopreventive, yet, there is limited information about its antiepileptic effects. Moreover, its poor solubility in water and low bioavailability are the challenging issues. In the present study, we aimed to investigate effects of free resveratrol and resveratrol delivered in amphipathic liposomal delivery system, which has a high blood-brain barrier crossing potential, on penicillin-induced epileptic seizure model. For this purpose, adult male Sprague-Dawley rats were divided into four groups as saline (Control), liposome (LIP), free resveratrol (RES) and resveratrol+liposome (RES+LIP). Penicillin-induced epileptic activity was recorded for 120 min by electrocorticography. Glutathione S-transferase (GST), Glutathione (GSH), Superoxide dismutase (SOD) and Malondialdehyde (MDA) assays were performed in brain tissues collected. Our results showed that RES+LIP was the most effective anticonvulsant treatment on penicillin-induced epileptic seizures when compared to control, as RES+LIP immediately decreased the number of spikes per minute. GST and SOD activity, as well as the GSH levels, were significantly increased in the RES+LIP group as compared with the control group. Also, the MDA levels were significantly higher in the RES+LIP compared to RES and control groups. In conclusion, RES+LIP treatment was more effective on the decrease in spike frequency and spike amplitudes than other treatments. Our results suggest that the RES+LIP is more effective than RES on penicillin-induced epileptiform activity.