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

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.

L4-to-L4 nerve root transfer for hindlimb hemiplegia after hypertensive intracerebral hemorrhage

There is no effective treatment for hemiplegia after hypertensive intracerebral hemorrhage. Considering that the branches of L4 nerve roots in the lumbar plexus root control the movement of the lower extremity anterior and posterior muscles, we investigated a potential method of nerve repair using the L4 nerve roots. Rat models of hindlimb hemiplegia after a hypertensive intracerebral hemorrhage were established by injecting autogenous blood into the posterior limb of internal capsule. The L4 nerve root on the healthy side of model rats was transferred and then anastomosed with the L4 nerve root on the affected side to drive the extensor and flexor muscles of the hindlimbs. We investigated whether this method can restore the flexible movement of the hindlimbs of paralyzed rats after hypertensive intracerebral hemorrhage. In a beam-walking test and ladder rung walking task, model rats exhibited an initial high number of slips, but improved in accuracy on the paretic side over time. At 17 weeks after surgery, rats gained approximately 58.2% accuracy from baseline performance and performed ankle motions on the paretic side. At 9 weeks after surgery, a retrograde tracing test showed a large number of fluoro-gold-labeled motoneurons in the left anterior horn of the spinal cord that supports the L4-to-L4 nerve roots. In addition, histological and ultramicrostructural findings showed axon regeneration of motoneurons in the anterior horn of the spinal cord. Electromyography and paw print analysis showed that denervated hindlimb muscles regained reliable innervation and walking coordination improved. These findings suggest that the L4-to-L4 nerve root transfer method for the treatment of hindlimb hemiplegia after hypertensive intracerebral hemorrhage can improve the locomotion of hindlimb major joints, particularly of the distal ankle. Findings from study support that the L4-to-L4 nerve root transfer method can effectively repair the hindlimb hemiplegia after hypertensive intracerebral hemorrhage. All animal experiments were approved by the Animal Ethics Committee of the First Affiliated Hospital of Nanjing Medical University (No. IACUC-1906009) in June 2019.