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Vol 110, No 8 (2024)
EXPERIMENTAL ARTICLES
EEG sensorimotor rhythms dynamics in children with cerebral palsy during the course of neurorehabilitation, depending in the success of their imagination of movements
Abstract
An analysis of changes in sensorimotor rhythms of the electroencephalogram (EEG) and features of the restoration of motor functions during a course of neurorehabilitation using a non-invasive brain-computer-hand exoskeleton interface was carried out in 50 children aged 7–15 years of both sexes suffering from cerebral palsy (CP). EEG was recorded in 32 leads under conditions of rest and kinesthetic imagination of hand extension movements. Depending on the success of the classifier program in determining imaginary states based on the EEG pattern, the children were divided into two groups – with high and low success when imagining movements. In children of the studied groups, when undergoing a course of neurorehabilitation, differences were revealed in the nature of changes in EEG amplitude in the sensorimotor mu (8–13 Hz) and beta (15–25 Hz) rhythms frequency ranges. When imagining movements of the right hand, intergroup differences for the mu rhythm reached the level of statistical significance in the medial electrodes of the fronto-central and parietal areas of the neocortex, for the beta rhythm – in the medial lead of the parietal region. Children in the group with high success showed a decrease or slight increase in the amplitude of the mu- and beta rhythm in these brain areas at the last session of the course compared to the first. We hypothesize that children in this group are not only better able to kinesthetically imagine movements throughout the course of neurorehabilitation, but also, based on feedback signals, learn to effectively adjust their strategies for movement imagination. Children in the group with low success showed an increase in the amplitude of sensorimotor rhythms in these brain areas, indicating the development of inhibition in the frontoparietal motor network. Patients, whose conditions were determined more accurately by the classifier, achieved higher rates of motor rehabilitation. The results of the study are important for clarifying the brain mechanisms of motor functions restoration in patients with cerebral palsy under the influence of a course of neurorehabilitation.
1223-1237
Intranasal administration of GRP78 protein (HSPA5) counteracts the neurodegeneration in the locus coeruleus in a model of chronic sleep restriction in rats
Abstract
Chronic sleep restriction (sleep less than 6 hours per day) due to the workload and a decrease in sleep quality is an endemic disease in modern society. Chronic sleep deprivation causes serious neuropsychiatric disorders associated with irreversible neurodegenerative changes in the brain. The search for pharmacological agents that can reduce the risk of neurodegeneration as a result of chronic sleep loss is an urgent task issue for biomedicine. Intranasal administration of glucose-regulated 78 kDa heat shock protein (GRP78) has a neuroprotective effect in a rat model of Parkinson´s disease. The neuroprotective potential of intranasally administered GRP78 in chronic sleep deprivation has not been previously studied. The aim of the study is to find out whether preventive intranasal administration of GRP78 is able to weaken and/or stop the process of neurodegeneration in the locus coeruleus in the model of chronic sleep restriction (SR) in rats. The study was conducted on 6 months old male Wistar rats. For sleep deprivation, a validated method of a swinging platform was used in the mode: 3 hours of sleep deprivation and 1 hour of rest continuously for 5 days. Recombinant human protein GRP78 was administered intranasally two days before the start of SR and during 5 days of SR. Cellular and molecular changes in the locus coeruleus during SR and during the administration of GRP78 were studied using immunohistochemistry and Western blotting. It was shown that chronic SR leads to the degeneration of 30% of noradrenergic neurons in the locus coeruleus, that was associated with an increase in the levels of activated caspases-3 and 9. This indicates the development of apoptosis along the mitochondrial pathway. No signs of reactive microgliosis were found in the model of chronic SR in rats. We have demonstrated that intranasally administered GRP78 penetrates and accumulates in the neurons of the locus coeruleus, GRP78 counteracts the death of neurons along the path of apoptosis. The data obtained allows to consider GRP78 as a potential neuroprotective agent for the prevention of pathological consequences of chronic sleep deprivation.
1238-1252
Application of lactoferrin for the prevention and restoration of bone tissue in Wistar rats under conditions of hindlimb unloading
Abstract
The influence of gravitational unloading (antiorthostatic suspension) and subsequent recovery on the mineral density and mechanical properties of the femoral and tibial bones of Wistar rats was studied with oral administration of a biotechnological analog of human lactoferrin (200 mg/kg) derived from the milk of producer goats. Bone mineral density was determined by dual-energy X-ray absorptiometry, and strength and stiffness were assessed through three-point bending tests.
It was shown that gravitational unloading for 21 days led to a decrease in the mineral density of the tibial and femoral bones. The administration of lactoferrin did not significantly affect the mineral density or projected area of the studied bones. No statistically significant differences in mechanical stiffness were found between the experimental groups, but after readaptation, the ultimate strength was significantly higher in the groups that received lactoferrin. Thus, the obtained results may indicate the potential of lactoferrin preparations as prophylactic agents for maintaining bone strength. At the same time, maintaining bone mineral density under deficit-stimulating conditions requires consideration of alternative dosages and delivery methods of the drug.
1253-1263
Effect of preservation on changes in the volume of corneal endothelial cells in an environment with a high concentration of potassium
Abstract
The experimental study of preservation length on the effect of high potassium concentration in the medium on the volume of human corneal endothelial cells was done. The results of the study of individual samples of fragments of donor material and the values calculated using joined data after hypothermic preservation for 4 and 10 days are presented. The increase of the time when cornea samples are kept in preservation medium (Eusol-C) at 4℃ led to a decrease in the average value (M ± SEM) of cell swelling indicator (N) in a potassium medium from 1.055 ±0.001; n = 982 to 1.014±0.001; n = 338; after 4 and 10 days, respectively. Student’s-t test for independent samples showed a high degree of significance for the difference between these values (p = 2E-76). Identification of the proportion of cells capable to swell in a medium with a high content of potassium ions (N > 1), reflecting the electrogenic activity in these cells, showed a decrease of this indicator in the studied groups with increasing duration of preservation (94.3% and 56.8% after 4 and 10 days, respectively).
Based on the results of the study, it is suggested that the values of endothelial cells swelling in a potassium environment can serve as indicators of the cells’ ability to restore electrogenic transport. It is concluded that the study of cell swelling in a medium with a high content of potassium ions can provide information for predicting the functionality of the graft.
1264-1272