Effects of transcranial focal electrical stimulation via tripolar concentric ring electrodes on pentylenetetrazole-induced seizures in rats

Purpose: To study the effects of noninvasive transcranial focal electrical stimulation (TFS) via tripolar concentric ring electrodes (TCRE) on the electrographic and behavioral activity from pentylenetetrazole (PTZ)-induced seizures in rats. Methods: The TCREs were attached to the rat scalp. PTZ was administered and, after the first myoclonic jerk was observed, TFS was applied to the TFS treated group. The electroencephalogram (EEG) and behavioral activity were recorded and studied. Results: In the case of the TFS treated group, after TFS, there was a significant (p = 0.001) decrease in power compared to the control group in delta, theta, and alpha frequency bands. The number of myoclonic jerks was significantly different (p = 0.002) with median of 22 and 4.5 for the control group and the TFS treated groups, respectively. The duration of myoclonic activity was also significantly different (p = 0.031) with median of 17.56 min for the control group versus 8.63 min for the TFS treated group. At the same time there was no significant difference in seizure onset latency and maximal behavioral seizure activity score between control and TFS treated groups. Conclusions: TFS via TCREs interrupted PTZ-induced seizures and electrographic activity was reduced toward the “baseline.” The significantly reduced electrographic power, number of myoclonic jerks, and duration of myoclonic activity of PTZ-induced seizures suggests that TFS may have an anticonvulsant effect

Ischemia–reperfusion impairs blood–brain barrier function and alters tight junction protein expression in the ovine fetus

The blood–brain barrier is a restrictive interface between the brain parenchyma and the intravascular compartment. Tight junctions contribute to the integrity of the blood–brain barrier. Hypoxic–ischemic damage to the blood–brain barrier could be an important component of fetal brain injury. We hypothesized that increases in blood–brain barrier permeability after ischemia depend upon the duration of reperfusion and that decreases in tight junction proteins are associated with the ischemia-related impairment in blood–brain barrier function in the fetus. Blood–brain barrier function was quantified with the blood-to-brain transfer constant (Ki) and tight junction proteins by Western immunoblot in fetal sheep at 127 days of gestation without ischemia, and 4, 24, or 48 h after ischemia. The largest increase in Ki (P \u3c 0.05) was 4 h after ischemia. Occludin and claudin-5 expressions decreased at 4 h, but returned toward control levels 24 and 48 h after ischemia. Zonula occludens-1 and -2 decreased after ischemia. Inverse correlations between Ki and tight junction proteins suggest that the decreases in tight junction proteins contribute to impaired blood–brain barrier function after ischemia. We conclude that impaired blood–brain barrier function is an important component of hypoxic–ischemic brain injury in the fetus, and that increases in quantitatively measured barrier permeability (Ki) change as a function of the duration of reperfusion after ischemia. The largest increase in permeability occurs 4 h after ischemia and blood–brain barrier function improves early after injury because the blood–brain barrier is less permeable 24 and 48 than 4 h after ischemia. Changes in the tight junction molecular composition are associated with increases in blood–brain barrier permeability after ischemia

Experimental assessments of metallic and metal oxide nanoparticles toxicity

Nanoparticles of metals and their oxides (Me-NPs) are of special interest in the light of health risks assessment and management, because, along with engineered Me-NPs, there exists usually a substantial fraction of nanoscale ("ultrafine") particles of the same substances within the particle size distribution of condensation aerosols generated by arc-welding, metallurgical, and some chemical technologies. The nonspecific responses of the organism to the impact of Me-NP included: changes in the cytological and some biochemical characteristics of the bronchoalveolar lavage fluid caused by the deposition of particles in the lower airways, various manifestations of systemic toxicity including significant damage to the liver and kidneys, moderate neurological disturbances associated with possible penetration of Me-NP into the brain from the blood as well as from the nasal mucous membrane along the olfactory pathway, a paradoxically low manifestation of pulmonary pathology due to low chronic retention of nanoparticles in the lungs, and a genotoxic effect on the organism level. The toxicity and even genotoxicity of Me-NPs can be significantly attenuated by adequately composed combinations of some bioactive agents in innocuous doses. © Published under licence by IOP Publishing Ltd.Government Council on Grants, Russian FederationMinistry of Science and Higher Education of the Russian Federation: 3.9534.2017/8.9The research was partially supported by the Ministry of Science and Higher Education of the Russian Federation (project 3.9534.2017/8.9) and by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). The equipment of the Ural Centre for Shared Use “Modern Nanotechnology” UrFU was used