Intensive treadmill training promotes cognitive recovery after cerebral ischemia-reperfusion in juvenile rats

Therapeutic effects of intracerebral transplantation of human modified bone marrow-derived stromal cells (SB623) with voluntary and forced exercise in a rat model of ischemic stroke

Ischemic stroke results in significant long-term disability and mortality worldwide. Although existing therapies, such as recombinant tissue plasminogen activator and mechanical thrombectomy, have shown promise, their application is limited by stringent conditions. Mesenchymal stem cell (MSC) transplantation, especially using SB623 cells (modified human bone marrow-derived MSCs), has emerged as a promising alternative, promoting neurogenesis and recovery. This study evaluated the effects of voluntary and forced exercise, alone and in combination with SB623 cell transplantation, on neurological and psychological outcomes in a rat model of ischemic stroke. Male Wistar rats that had undergone middle cerebral artery occlusion (MCAO) were divided into six groups: control, voluntary exercise (V-Ex), forced exercise (F-Ex), SB623 transplantation, SB623 + V-Ex, and SB623 + F-Ex. Voluntary exercise was facilitated using running wheels, while forced exercise was conducted on treadmills. Neurological recovery was assessed using the modified neurological severity score (mNSS). Psychological symptoms were evaluated through the open field test (OFT) and forced swim test (FST), and neurogenesis was assessed via BrdU labeling. Both exercise groups exhibited significant changes in body weight post-MCAO. Both exercises enhanced the treatment effect of SB623 transplantation. The forced exercise showed a stronger treatment effect on ischemic stroke than voluntary exercise alone, and the sole voluntary exercise improved depression-like behavior. The SB623 + F-Ex group demonstrated the greatest improvements in motor function, infarct area reduction, and neurogenesis. The SB623 + V-Ex group was most effective in alleviating depression-like behavior. Future research should optimize these exercise protocols and elucidate the underlying mechanisms to develop tailored rehabilitation strategies for stroke patients.

Coenzyme Q10 and exercise training reinstate middle cerebral artery occlusion-induced behavioral deficits and hippocampal long-term potentiation suppression in aging rats

RATIONAL

Patients experience post-stroke cognitive impairment during aging. To date, no specific treatment solution has been reported for this disorder.

OBJECTIVE

The purpose of this study was to evaluate the effects of exercise training and coenzyme Q10 supplementation on middle cerebral artery occlusion (MCAO) induced behavioral impairment, long-term potentiation inhibition and cerebral infarction size in aging rats.

METHODS

Fifty aging male rats underwent MCAO surgery and were randomly distributed in to the following groups: 1-Sham, 2- control, 3- Coenzyme Q10, 4- Exercise training and 5- Exercise training with Q10 supplementation (Ex + Q10). Aerobic training groups were allowed to run on a treadmill for 12 weeks. Q10 (50 mg/kg) was administered intragastrically by gavage. Morris water maze, shuttle box and elevated plus maze tests were used to evaluate cognitive function. The population spike (PS) amplitude and slope of excitatory postsynaptic potentials (EPSP) in the dentate gyrus area were recorded as a result of perforant pathway electrical stimulation.

RESULTS

Our study showed that Q10 and aerobic training alone ameliorate spatial memory in the acquisition phase, but have no effect on spatial memory in the retention phase. Q10 and exercise training synergistically promoted spatial memory in the retention phase. Q10 and exercise training separately and simultaneously mitigated cerebral ischemia-induced passive avoidance memory impairment in acquisition and retention phases. The EPSP did not differ between the groups, but exercise training and Q10 ameliorate the PS amplitude in hippocampal responses to perforant path stimulation. Exercising and Q10 simultaneously reduced the cerebral infarction volume.

CONCLUSION

Collectively, the findings of the present study imply that 12 weeks of aerobic training and Q10 supplementation alone can simultaneously reverse cerebral ischemia induced neurobehavioral deficits via amelioration of synaptic plasticity and a reduction in cerebral infarction volume in senescent rats.

Potential effect of physical exercise on the downregulation of BDNF mRNA expression in rat hippocampus following intracerebral hemorrhage

OBJECTIVES

Physical exercise is known to induce expression of the neuroprotective brain derived neurotrophic factor (BDNF) in the hippocampus. This study examined the effects of physical exercise on hippocampal BDNF expression and the potential benefits for preventing remote secondary hippocampal damage and neurological impairment following intracerebral hemorrhage (ICH).

MATERIALS AND METHODS

Wistar rats were randomly assigned to sham-operated, ICH, and ICH followed by exercise (ICH/Ex) groups. The two ICH groups were injected with type IV collagenase into the left basal ganglia, while sham animals were injected with equal-volume saline. The ICH/Ex group rats ran on a treadmill at 11 m/min for 30 min/day from day 3 to 16 post-ICH. All animals were examined for neurological function on day 2 pretreatment and from day 3 to 15 posttreatment, for spontaneous motor activity in the open field on day 15, and for cognitive ability using the object location test on day 16. Animals were then euthanized and bilateral hippocampi collected for gene expression analyses.

RESULTS

Experimental ICH induced neurological deficits that were not reversed by exercise. In contrast, ICH did not alter spontaneous activity or object location ability. Expression of BDNF mRNA of the ICH group was significantly downregulated in the ipsilateral hippocampus compared to the SHAM group, but this downregulation was not shown in the ICH/Ex group. The ICH/Ex group showed the downregulation of caspase-3 mRNA expression in the contralateral hippocampus compared to the SHAM group, while neither ICH nor exercise influenced toll-like receptor 4 mRNA expression.

CONCLUSIONS

ICH induced the secondary BDNF downregulation in the hippocampus remote from the lesion, whereas physical exercise might partially mitigate the downregulation.

Exercise Intervention Modulates Synaptic Plasticity by Inhibiting Excessive Microglial Activation via Exosomes

Background

Exosomes can activate microglia to modulate neural activity and synaptic plasticity by phagocytosis of neural spines or synapses. Our previous research found that an early 4-week exercise intervention in middle cerebral artery occlusion (MCAO) rats can promote the release of exosomes and protect the brain. This study intended to further explore the intrinsic mechanism of neuroprotection by exosome release after exercise.

Methods

Rats were randomly divided into four groups: the sham operation (SHAM), middle cerebral artery occlusion (MCAO) with sedentary intervention (SED-MCAO), MCAO with exercise intervention (EX-MCAO), and MCAO with exercise intervention and exosome injection (EX-MCAO-EXO). Modified neurological severity score (mNSS), cerebral infarction volume ratio, microglial activation, dendritic complexity, and expression of synaptophysin (Syn) and postsynaptic density protein 95 (PSD-95) were detected after 28 days of intervention.

Results

(1) The exercise improved body weight and mNSS score, and the survival state of the rats after exosome infusion was better. (2) Compared with the SED-MCAO group, the EX-MCAO (P = 0.039) and EX-MCAO-EXO groups (P = 0.002) had significantly lower cerebral infarct volume ratios (P < 0.05), among which the EX-MCAO-EXO group had the lowest (P = 0.031). (3) Compared with the SED-MCAO group, the EX-MCAO and EX-MCAO-EXO groups had a significantly decreased number of microglia (P < 0.001) and significantly increased process length/cell (P < 0.01) and end point/cell (P < 0.01) values, with the EX-MCAO-EXO group having the lowest number of microglia (P = 0.036) and most significantly increased end point/cell value (P = 0.027). (4) Compared with the SED-MCAO group, the total number of intersections and branches of the apical and basal dendrites in the EX-MCAO and EX-MCAO-EXO groups was increased significantly (P < 0.05), and the increase was more significant in the EX-MCAO-EXO group (P < 0.05). (5) The expression levels of Syn and PSD-95 in the EX-MCAO (P_Syn = 0.043, P_PSD−95 = 0.047) and EX-MCAO-EXO groups were significantly higher than those in the SED-MCAO group (P < 0.05), and the expression levels in the EX-MCAO-EXO group were significantly higher than those in the EX-MCAO group (P < 0.05).

Conclusion

Early exercise intervention after stroke can inhibit the excessive activation of microglia and regulate synaptic plasticity by exosome release.

Complicated Role of Exercise in Modulating Memory: A Discussion of the Mechanisms Involved

Evidence has shown the beneficial effects of exercise on learning and memory. However, many studies have reported controversial results, indicating that exercise can impair learning and memory. In this article, we aimed to review basic studies reporting inconsistent complicated effects of exercise on memory in rodents. Also, we discussed the mechanisms involved in the effects of exercise on memory processes. In addition, we tried to find scientific answers to justify the inconsistent results. In this article, the role of brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (involved in synaptic plasticity and neurogenesis), and vascular endothelial growth factor, nerve growth factor, insulin-like growth factor 1, inflammatory markers, apoptotic factors, and antioxidant system was discussed in the modulation of exercise effects on memory. The role of intensity and duration of exercise, and type of memory task was also investigated. We also mentioned to the interaction of exercise with the function of neurotransmitter systems, which complicates the prediction of exercise effect via altering the level of BDNF. Eventually, we suggested that changes in the function of neurotransmitter systems following different types of exercise (depending on exercise intensity or age of onset) should be investigated in further studies. It seems that exercise-induced changes in the function of neurotransmitter systems may have a stronger role than age, type of memory task, or exercise intensity in modulating memory. Importantly, high levels of interactions between neurotransmitter systems and BDNF play a critical role in the modulation of exercise effects on memory performance.

Effects of Treadmill Exercise on the Expression Level of BAX, BAD, BCL-2, BCL-XL, TFAM, and PGC-1α in the Hippocampus of Thimerosal-Treated Rats

Thimerosal (THIM) induces neurotoxic changes including neuronal death and releases apoptosis inducing factors from mitochondria to cytosol. THIM alters the expression level of factors involved in apoptosis. On the other hand, the anti-apoptotic effects of exercise have been reported. In this study, we aimed to discover the effect of three protocols of treadmill exercise on the expression level of mitochondrial transcription factor A (TFAM), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), BCL-2-associated death (BAD), BCL-2-associated X (BAX), BCL-XL, and BCL-2 (a pro-survival BCL-2 protein) in the hippocampus of control and THIM-exposed rats. Male Wistar rats were used in this research. Real-time PCR was applied to assess genes expression. The results showed that THIM increased the expression of pro-apoptotic factors (BAD and BAX), decreased the expression of anti-apoptotic factors (BCL-2 and BCL-XL), and decreased the expression of factors involved in mitochondrial biogenesis (TFAM and PGC-1α). Treadmill exercise protocols reversed the effect of THIM on all genes. In addition, treadmill exercise protocols decreased the expression of BAD and BAX, increased the expression of BCL-2, and increased the expression of TFAM and PGC-1α in control rats. In conclusion, THIM induced a pro-apoptotic effect and disturbed mitochondrial biogenesis and stability, whereas treadmill exercise reversed these effects.