Remarkable cell recovery from cerebral ischemia in rats using an adaptive escalator-based rehabilitation mechanism

Effect of stress on the rehabilitation performance of rats with repetitive mild fluid percussion-induced traumatic brain injuries

Animal models of traumatic brain injury (TBI) have shown that impaired motor and cognitive function can be improved by physical exercise. However, not each animal with TBI can be well rehabilitated at the same training intensity due to a high inter-subject variability. Hence, this paper presents a two-stage wheel-based mixed-mode rehabilitation mechanism by which the effect of stress on the rehabilitation performance was investigated. The mixed-mode rehabilitation mechanism consists of a two-week adaptive and a one-week voluntary rehabilitation program as Stages 1 and 2, respectively. In Stage 1, the common over and undertraining problem were completely resolved due to the adaptive design, and rats ran voluntarily over a 30-min duration in Stage 2. The training intensity adapted to the physical condition of all the TBI rats at all times in Stage 1, and then the self-motivated running rats were further rehabilitated under the lowest level of stress in Stage 2. For comparison purposes, another group of rats took a 3-week adaptive rehabilitation program. During the 3-week program, the rehabilitation performance of the rats were assessed using modified neurologic severity score (mNSS) and an 8-arm radial maze. Surprisingly, the group taking the mixed mode program turned out to outperform its counterpart in terms of mNSS. The mixed-mode rehabilitation mechanism was validated as an effective and efficient way to help rats restore motor, neurological and cognitive function after TBI. It was validated that the rehabilitation performance can be optimized under the lowest level of stress.

Senkyunolide H Affects Cerebral Ischemic Injury through Regulation on Autophagy of Neuronal Cells via P13K/AKT/mTOR Signaling Pathway

Cerebral ischemia (CI) is associated with high global incidence and risk; therefore, its rapid and reliable therapeutic management is essential for protecting patients' lives and improving health. Senkyunolide H (SH) is remarkably effective against phlebosclerosis, oxidation, and apoptosis. Blood-brain barrier is the main obstacle impeding the delivery of drugs and xenobiotics to brain areas. Drugs' loading in nanoparticles can overcome the blood-brain barrier obstacle and thus directly and completely act on brain tissue, and such a loading can also change the half-life of drugs in vivo and lower the dosage requirement of drugs. In this study, we loaded the SH in lipid nanoparticles to improve its delivery to the brain for the therapy of CI. Thus, this study preliminarily analyzed the mechanism of SH-loaded nanoparticles in CI. The SH-loaded lipid nanoparticles were prepared and characterized with electron microscopy and PS potentiometery. The SH-loaded nanoparticles were intraperitoneally administered to CI-induced rats and brain tissue water content, and neuronal apoptosis and autophagy-associated proteins were determined. Our assays revealed SH-loaded nanoparticle's ability to reduce nerve injury and brain tissue water content in rats with CI and inhibit the apoptosis and autophagy of their neuronal cells (NCs). Additionally, under intervention with SH-loaded nanoparticles, P13K/AKT/mTOR pathway-associated proteins in brain tissue of rats decreased. As the assay results showed, SH-loaded nanoparticles can suppress the autophagy of NCs through medicating P13K/AKT/mTOR pathway and lower apoptosis, thus delivering the effect of treating CI. Results of this study indicate SH-loaded nanoparticles as promising strategy for delivery SH to brain areas for treating CI.

Behavioral Assessment of Sensory, Motor, Emotion, and Cognition in Rodent Models of Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the second most common type of stroke and has one of the highest fatality rates of any disease. There are many clinical signs and symptoms after ICH due to brain cell injury and network disruption resulted from the rupture of a tiny artery and activation of inflammatory cells, such as motor dysfunction, sensory impairment, cognitive impairment, and emotional disturbance, etc. Thus, researchers have established many tests to evaluate behavioral changes in rodent ICH models, in order to achieve a better understanding and thus improvements in the prognosis for the clinical treatment of stroke. This review summarizes existing protocols that have been applied to assess neurologic function outcomes in the rodent ICH models such as pain, motor, cognition, and emotion tests. Pain tests include mechanical, hot, and cold pain tests; motor tests include the following 12 types: neurologic deficit scale test, staircase test, rotarod test, cylinder test, grid walk test, forelimb placing test, wire hanging test, modified neurologic severity score, beam walking test, horizontal ladder test, and adhesive removal test; learning and memory tests include Morris water maze, Y-maze, and novel object recognition test; emotion tests include elevated plus maze, sucrose preference test, tail suspension test, open field test, and forced swim test. This review discusses these assessments by examining their rationale, setup, duration, baseline, procedures as well as comparing their pros and cons, thus guiding researchers to select the most appropriate behavioral tests for preclinical ICH research.

Rehabilitation Effects of Fatigue-Controlled Treadmill Training After Stroke: A Rat Model Study

Background: Traditional rehabilitation with uniformed intensity would ignore individual tolerance and introduce the second injury to stroke survivors due to overloaded training. However, effective control of the training intensity of different stroke survivors is still lacking. The purpose of the study was to investigate the rehabilitative effects of electromyography (EMG)-based fatigue-controlled treadmill training on rat stroke model. Methods: Sprague-Dawley rats after intracerebral hemorrhage and EMG electrode implantation surgeries were randomly distributed into three groups: the control group (CTRL, n = 11), forced training group (FOR-T, n = 11), and fatigue-controlled training group (FAT-C, n = 11). The rehabilitation interventions were delivered every day from day 2 to day 14 post-stroke. No training was delivered to the CTRL group. The rats in the FOR-T group were forced to run on the treadmill without rest. The fatigue level was monitored in the FAT-C group through the drop rate of EMG mean power frequency, and rest was applied to the rats when the fatigue level exceeded the moderate fatigue threshold. The speed and accumulated running duration were comparable in the FAT-C and the FOR-T groups. Daily evaluation of the motor functions was performed using the modified Neurological Severity Score. Running symmetry was investigated by the symmetry index of EMG bursts collected from both hind limbs during training. The expression level of neurofilament-light in the striatum was measured to evaluate the neuroplasticity. Results: The FAT-C group showed significantly lower modified Neurological Severity Score compared with the FOR-T (P ≤ 0.003) and CTRL (P ≤ 0.003) groups. The FAT-C group showed a significant increase in the symmetry of hind limbs since day 7 (P = 0.000), whereas the FOR-T group did not (P = 0.349). The FAT-C group showed a higher concentration of neurofilament-light compared to the CTRL group (P = 0.005) in the unaffected striatum and the FOR-T group (P = 0.021) in the affected striatum. Conclusion: The treadmill training with moderate fatigue level controlled was more effective in motor restoration than forced training. The fatigue-controlled physical training also demonstrated positive effects in the striatum neuroplasticity. This study indicated that protocol with individual fatigue-controlled training should be considered in both animal and clinical studies for better stroke rehabilitation.

Individualized Running Wheel System with a Dynamically Adjustable Exercise Area and Speed for Rats Following Ischemic Stroke

Background

An innovative animal running wheel with an individualized design was implemented for the rehabilitation of rats following ischemic stroke.

Material/Methods

The design of the running wheel platform included the running wheel and a side plate for exercise area adjustments. A U-curve with a width of 2 cm was drawn on the lower half of the side plate for the dynamic adjustments of five infrared (IR) sensors based on the physical fitness of the rats. The individualized training process for this running wheel consisted of 2 days of free training to record their average and maximum speeds, 3 days of progressive training to determine their exercise areas, and 2 weeks of normal training based on their average speeds, maximum speeds, and exercise areas. Blood samples were obtained from the tail veins of all rats before the operations and on Days 14, 21, and 28 postsurgery to measure cortisol levels. The motor function tests were performed on Days 7 and 28 postsurgery. On Day 28 postsurgery, the rats were sacrificed under anesthesia, and their brains were removed for Nissl and H&E staining.

Results

On Day 28 after surgery, the motor function, lesion volume, and cell damage of the DEARW and control groups differed significantly, indicating that this device is effective for stroke rehabilitation.

Conclusions

The outcomes of the rats that were rehabilitated using the newly designed training system were better than those of their control-group counterparts, indicating the advantages of this designed system.

Development of a three-channel automatic climbing training system for rat rehabilitation after ischemic stroke

This paper reports the development of a three-channel automatic speed-matching climbing training system that could train three rats at the same time for rehabilitation after an ischemic stroke. An infrared (IR) remote sensor was installed at the end of each channel to monitor the real-time position of a climbing rat. This research was carried out in five stages: i) system design; ii) hardware circuit; iii) running speed control; iv) functional testing; and v) verification using an animal model of cerebral stroke. The rehabilitated group significantly outperformed the middle cerebral artery occlusion (MCAo) sedentary group in the rota-rod and inclined plate tests 21 days after a stroke. The rehabilitated group also had a cerebral infarction volume of 28.34±19.4%, far below 56.81±18.12% of the MCAo group 28 days after the stroke, validating the effectiveness of this training platform for stroke rehabilitation. The running speed of the climbing rehabilitation training platform was designed to adapt to the physical conditions of subjects, and overtraining injuries can be completely prevented accordingly.