Effects of treadmill training on limb motor function and acetylcholinesterase activity in rats with stroke

Neuroprotective effect of long-term resistance physical exercise against memory damage elicited by a lipopolysaccharide-induced neuroinflammation model in male rats

Resistance exercise training (RET) is considered an excellent tool for preventing diseases with an inflammatory background. Its neuroprotective, antioxidant, and anti-inflammatory properties are responsible for positively modulating cholinergic and oxidative systems, promoting neurogenesis, and improving memory. However, the mechanisms behind these actions are largely unknown. In order to investigate the pathways related to these effects of exercise, we conducted a 12-week long-term exercise training protocol and used lipopolysaccharide (LPS) to induce damage to the cortex and hippocampus of male Wistar rats. The cholinergic system, oxidative stress, and histochemical parameters were analyzed in the cerebral cortex and hippocampus, and memory tests were also performed. It was observed that LPS: (1) caused memory loss in the novel object recognition (NOR) test; (2) increased the activity of acetylcholinesterase (AChE) and Iba1 protein density; (3) reduced the protein density of brain-derived neurotrophic factor (BDNF) and muscarinic acetylcholine receptor M1 (CHRM1); (4) elevated the levels of lipid peroxidation (TBARS) and reactive species (RS); and (5) caused inflammatory damage to the dentate gyrus. RET, on the other hand, was able to prevent all alterations induced by LPS, as well as increase per se the protein density of the alpha-7 nicotinic acetylcholine receptor (nAChRα7) and Nestin, and the levels of protein thiols (T-SH). Overall, our study elucidates some mechanisms that support resistance physical exercise as a valuable approach against LPS-induced neuroinflammation and memory loss.

Possible cerebroprotective effect of citronellal: molecular docking, MD simulation and in vivo investigations

This study focused on molecular docking, dynamic simulation, and in vivo approaches to examine the molecular interactions between citronellal (CT) and neurotoxic proteins. In silico studies of CT were performed using proteins involved in the pathophysiology of stroke, such as interleukin-6 (IL-6), interleukin-12 (IL-12), TNF-α, and nitric oxide synthase (NOS), to determine the binding affinity based on their interactions. The docking results of CT revealed that, among the targets, NOS had a better binding energy of -6.4 Kcal/mol. NOS showed good hydrophobic interactions: TYR A, 347; VAL A, 352; PRO A, 350; TYR A, 373 amino acids. Interactions with IL-6, TNF-α, and IL-12 resulted in lower binding affinities of -3.7, -3.9 and -3.1 Kcal/mol. Based on molecular dynamics simulations of 100 ns, the binding affinity of CT (-66.782 ± 7.309 kJ/mol) was well complemented, and NOS stability at the docked site was confirmed. In in vivo studies, cerebral stroke was induced by occlusion of the bilateral common carotid arteries for 30 min and reperfusion for 4 h. CT treatment protected the brain by decreasing cerebral infarction size, increasing GSH(p < 0.001***), decreasing MPO (p < 0.001***), MDA (p < 0.001***), NO production (p < 0.01**), and AChE (p < 0.001***) compared to stroke rats. Histopathological examination revealed that CT treatment reduced the severity of cerebral damage. The investigation concluded that CT strongly binds to NOS, as observed in molecular docking and dynamic simulation studies, which are involved in nitric oxide production, leading to cerebral damage, and CT treatment reduces NO production and oxidative stress parameters, and increases antioxidants via inhibition of NOS function.Communicated by Ramaswamy H. Sarma.

Neuroprotective Effect of Piclamilast-Induced Post-Ischemia Pharmacological Treatment in Mice

Various studies have evidenced the neuroprotective role of PDE4 inhibitors. However, whether PDE4 inhibitor, Piclamilast pharmacological post-treatment is protective during cerebral ischemia reperfusion-induced injury remains unknown. Therefore, this study design included testing the hypothesis that Piclamilast administered at the beginning of a reperfusion phase (Piclamilast pPost-trt) shows protective effects and explores & probes underlying downstream mechanisms. Swiss albino male mice were subjected to global ischemic and reperfusion injury for 17 min. The animals examined cerebral infarct size, biochemical parameters, inflammatory mediators, and motor coordination. For memory, assessment mice were subjected to morris water maze (MWM) and elevated plus maze (EPM) test. Histological changes were assessed using HE staining. Piclamilast pPost-trt significantly reduced I/R injury-induced deleterious effects on biochemical parameters of oxidative stress, inflammatory parameters, infarct size, and histopathological changes, according to the findings. These neuroprotective effects of pPost-trt are significantly abolished by pre-treatment with selective CREB inhibitor, 666-15. Current study concluded that induced neuroprotective benefits of Piclamilast Post-trt, in all probability, maybe mediated through CREB activation. Hence, its neuroprotective effects can be further explored in clinical settings.

Exercise Improves Recognition Memory and Acetylcholinesterase Activity in the Beta Amyloid-Induced Rat Model of Alzheimer's Disease

Objective

A correlation between physical exercise and cognitive improvement has been found in Alzheimer's disease (AD). This study aimed to investigate the effects of aerobic and resistance exercise on the recognition memory and acetylcholinesterase (AChE) activity in beta amyloid (Aβ) model of AD in rat.

Materials and Methods

Fifty male 8-week-old Wistar rats (250-280 g) were divided into 5 groups (n = 10 each) of control, sham surgery, Aβ-received sedentary, Aβ-received with aerobic exercise and Aβ-received with resistance exercise. AD was induced by intracerebroventricular injection of Aβ_25-35 peptide. The sham surgery group received normal saline using the same route and condition. Two groups of Aβ-received animals were trained by treadmill for aerobic exercise and by ladder for strength exercise for 8 weeks (4 days/week). Novel object recognition (NOR) task was used to assess recognitional memory in groups. AChE activity in the brain tissue was assessed using the Spectrophotometry method.

Results

There was no significant difference in memory index and AChE activity between the sham surgery and control groups (p > 0.05). Also, impairment of NOR indices was seen in the Aβ-injected sedentary rats (p < 0.05). However, both aerobic and strength training improved the exploration index in this test (p < 0.05). Further, AChE activity increased in the Aβ-injected sedentary group but declined in the aerobic and resistance exercise groups (p < 0.01).

Conclusion

Aerobic and resistance exercise could improve recognition memory and decrease AChE activity in Aβ-induced AD in rats. The decrease in AChE activity may be one of the mechanisms by which exercise improves cognition and memory in AD.

Circulating extracellular vesicles in the aging process: impact of aerobic exercise

Our aim was to investigate transitory and delayed exercise effects on serum extracellular vesicles (EVs) in aging process. Male Wistar rats of 3-, 21-, and 26-month old were allocated into exercised and sedentary groups. The exercise protocol consisted in a daily moderate treadmill exercise (20 min daily during 2 weeks). Trunk blood was collected 1 and 18 h after the last exercise session, and circulating EVs were obtained. CD63 levels and acetylcholinesterase (AChE) activity were used as markers of exosome, a subtype of EVs. In addition, the quantification of amyloid-β (Aβ) levels and the oxidative status parameters, specifically reactive species content, superoxide dismutase (SOD) activity, and SOD1 content were evaluated. Aged rats showed reduced CD63 levels and increased AChE activity in circulating exosomes compared to young ones. Moreover, higher reactive species levels were found in circulating EVs of aged rats. Delayed exercise effects were observed on peripheral EVs, since CD63, reactive species content, and AChE activity were altered 18 h after the last exercise session. Our results suggest that the healthy aging process can modify circulating EVs profile, and exercise-induced beneficial effects may be related to its modulation on EVs.

Effects of the combined treatment of bone marrow stromal cells with mild exercise and thyroid hormone on brain damage and apoptosis in a mouse focal cerebral ischemia model

This study examined whether post-stroke bone marrow stromal cells (BMSCs) therapy combined with exercise (EX) and/or thyroid hormone (TH) could reduce brain damage in an experimental ischemic stroke in mice. Focal cerebral ischemia was induced under Laser Doppler Flowmetry (LDF) guide by 45 min of middle cerebral artery occlusion (MCAO), followed by 7 days of reperfusion in albino mice. BMSCs were injected into the right cerebral ventricle 24 h after MCAO, followed by daily injection of T3 (20 μg/100 g weight S.C) and 6 days of running on a treadmill. Infarct size, neurobehavioral test, TUNEL and BrdU positive cells were evaluated at 7 days after MCAO. Treatment with BMSCs and mild EX alone significantly reduced the infarct volume by 23% and 44%, respectively (both, p < 0.001). The BMSCs + TH, BMSCs + EX, and BMSCs + EX + TH combination therapies significantly reduced the infarct volume by 26%, 51%, and 70%, respectively (all, p < 0.001). A significant improvement in the neurobehavioral functioning was observed in the EX, BMSCs + EX, and BMSCs + EX+ TH groups (p < 0.001). The number of TUNEL-positive cells (a marker of apoptosis) was significantly reduced in the EX, BMSCs, BMSCs + EX, BMSCs + TH, and BMSCs + EX + TH groups (all, p < 0.001). Moreover, the combination therapy considerably increased BrdU-labeled cells in the subventricular zone (SVZ) (p < 0.01). Our findings indicated that the combined treatment of BMSCs with mild EX and TH more efficiently reduces the cerebral infarct size after stroke. More likely, these effects mediate via enchaining generation of new neuronal cells and the attenuation of apoptosis in ischemia stroke in young mice.

MODULATION OF KEY BIOCHEMICAL MARKERS RELEVANT TO STROKE BY ANTIARIS AFRICANA LEAF EXTRACT FOLLOWING CEREBRAL ISCHEMIA/REPERFUSION INJURY

BACKGROUND

Oxidative stress plays a significant role in stroke pathogenesis. Hence, plants rich in antioxidant phytochemicals have been suggested as effective remedies for prevention and treatment of stroke and other neurological diseases. Antiaris africana Engl. (Moraceae) is traditionally used for the management of brain-related problems but there is paucity of data on its anti-stroke potential.

MATERIALS AND METHODS

Ischemia/reperfusion injury was induced by a 30 min bilateral common carotid artery occlusion/ 2 h reperfusion (BCCAO/R) in the brain of male Wistar rats. A sham-operated group which was not subjected to BCCAO/R and a group subjected to BCCAO/R without treatment with MEA served as controls. The ameliorative effect of 14 days of pretreatment with 50 mg/kg or 100 mg/kg A. africana methanol leaf extract (MEA) on BCCAO/R-mediated alterations to key markers of oxidative stress (malondialdehyde, reduced glutathione, xanthine oxidase, superoxide dismutase, catalase and glutathione peroxidase) and neurochemical disturbances and excitotoxicity (myeloperoxidase, glutamine synthetase, Na⁺/K⁺ ATPase, acetylcholinesterase and tyrosine hydroxylase), was evaluated and compared with the effect produced by treatment with 20 mg/kg quercetin as a reference standard.

RESULTS

Results show that pretreatment with MEA significantly mitigated or reversed BCCAO/R-induced changes in the level or activity of the evaluated biochemical markers of oxidative stress, neurochemical dysfunction and excitotoxicity compared with the BCCAO/R untreated control group (p < 0.05). The effect produced by 100 mg/kg MEA was similar to that of the reference standard, quercetin.

CONCLUSION

These results revealed the neuroprotective potential of A. africana in stroke and other ischemia-related pathologies.

Enhancement of brain plasticity and recovery of locomotive function after lumbar spinal cord stimulation in combination with gait training with partial weight support in rats with cerebral ischemia

Lumbar spinal cord stimulation (LSCS) is reportedly effective for the recovery of locomotive intraspinal neural network, motor cortex and basal ganglia in animals with complete spinal cord injury and parkinsonism. We evaluated the effect of LSCS in combination with gait training on the recovery of locomotive function and brain plasticity using a rat model of brain ischemia. Adult male Sprague Dawley rats with ischemia were randomly assigned into one of four groups: sham treatment (group 1), LSCS only (group 2), LSCS with gait training and 50% (group 3) and 80% (group 4) of body weight support. Evaluations before randomization and 4weeks after intervention included motor scoring index, real-time PCR and Western blot. Motor scoring index was significantly improved after the intervention in groups 2 and 3. The ratio of phospho-protein kinase C (PKC) to PKC measured in the infarcted area tended to be higher in groups 3 and 4. Protein expression of mGluR2 and mRNA expression of mGluR1 measured in the contralateral cortex were lower in groups 3 and 4. The ratio of phospho-Akt to Akt and mRNA expression of vascular endothelial growth factor measured in the ischemic border zone were higher in group 2. The mRNA expression of MAP1b measured in the infarcted area was significantly higher in group 2. The findings suggest that LSCS and gait training with an adequate amount of body weight support may promote brain plasticity and facilitate the functional recovery.

Progesterone induces neuroprotection following reperfusion-promoted mitochondrial dysfunction after focal cerebral ischemia in rats

Organelle damage and increases in mitochondrial permeabilization are key events in the development of cerebral ischemic tissue injury because they cause both modifications in ATP turnover and cellular apoptosis/necrosis. Early restoration of blood flow and improvement of mitochondrial function might reverse the situation and help in recovery following an onset of stroke. Mitochondria and related bioenergetic processes can be effectively used as pharmacological targets. Progesterone (P4), one of the promising neurosteroids, has been found to be neuroprotective in various models of neurological diseases, through a number of mechanisms. This influenced us to investigate the possible role of P4 in the mitochondria-mediated neuroprotective mechanism in an ischemic stroke model of rat. In this study, we have shown the positive effect of P4 administration on behavioral deficits and mitochondrial health in an ischemic stroke injury model of transient middle cerebral artery occlusion (tMCAO). After induction of tMCAO, the rats received an initial intraperitoneal injection of P4 (8 mg/kg body weight) or vehicle at 1 h post-occlusion followed by subcutaneous injections at 6, 12 and 18 h. Behavioral assessment for functional deficits included grip strength, motor coordination and gait analysis. Findings revealed a significant improvement with P4 treatment in tMCAO animals. Staining of isolated brain slices from P4-treated rats with 2,3,5-triphenyltetrazolium chloride (TTC) showed a reduction in the infarct area in comparison to the vehicle group, indicating the presence of an increased number of viable mitochondria. P4 treatment was also able to attenuate mitochondrial reactive oxygen species (ROS) production, as well as block the mitochondrial permeability transition pore (mPTP), in the tMCAO injury model. In addition, it was also able to ameliorate the altered mitochondrial membrane potential and respiration ratio in the ischemic animals, thereby suggesting that P4 has a positive effect on mitochondrial bioenergetics. In conclusion, these results demonstrate that P4 treatment is beneficial in preserving the mitochondrial functions that are altered in cerebral ischemic injury and thus can help in defining better therapies.

Summary: Progesterone treatment is beneficial in preserving the altered mitochondrial functions in cerebral ischemic injury and thus can help in defining better therapies.

Defining Optimal Aerobic Exercise Parameters to Affect Complex Motor and Cognitive Outcomes after Stroke: A Systematic Review and Synthesis

Although poststroke aerobic exercise (AE) increases markers of neuroplasticity and protects perilesional tissue, the degree to which it enhances complex motor or cognitive outcomes is unknown. Previous research suggests that timing and dosage of exercise may be important. We synthesized data from clinical and animal studies in order to determine optimal AE training parameters and recovery outcomes for future research. Using predefined criteria, we included clinical trials of stroke of any type or duration and animal studies employing any established models of stroke. Of the 5,259 titles returned, 52 articles met our criteria, measuring the effects of AE on balance, lower extremity coordination, upper limb motor skills, learning, processing speed, memory, and executive function. We found that early-initiated low-to-moderate intensity AE improved locomotor coordination in rodents. In clinical trials, AE improved balance and lower limb coordination irrespective of intervention modality or parameter. In contrast, fine upper limb recovery was relatively resistant to AE. In terms of cognitive outcomes, poststroke AE in animals improved memory and learning, except when training was too intense. However, in clinical trials, combined training protocols more consistently improved cognition. We noted a paucity of studies examining the benefits of AE on recovery beyond cessation of the intervention.

Physical Exercise as a Diagnostic, Rehabilitation, and Preventive Tool: Influence on Neuroplasticity and Motor Recovery after Stroke

Stroke remains a leading cause of adult motor disabilities in the world and accounts for the greatest number of hospitalizations for neurological disease. Stroke treatments/therapies need to promote neuroplasticity to improve motor function. Physical exercise is considered as a major candidate for ultimately promoting neural plasticity and could be used for different purposes in human and animal experiments. First, acute exercise could be used as a diagnostic tool to understand new neural mechanisms underlying stroke physiopathology. Indeed, better knowledge of stroke mechanisms that affect movements is crucial for enhancing treatment/rehabilitation effectiveness. Secondly, it is well established that physical exercise training is advised as an effective rehabilitation tool. Indeed, it reduces inflammatory processes and apoptotic marker expression, promotes brain angiogenesis and expression of some growth factors, and improves the activation of affected muscles during exercise. Nevertheless, exercise training might also aggravate sensorimotor deficits and brain injury depending on the chosen exercise parameters. For the last few years, physical training has been combined with pharmacological treatments to accentuate and/or accelerate beneficial neural and motor effects. Finally, physical exercise might also be considered as a major nonpharmacological preventive strategy that provides neuroprotective effects reducing adverse effects of brain ischemia. Therefore, prestroke regular physical activity may also decrease the motor outcome severity of stroke.

The effect of sesamol on rats with ischemic stroke

[Purpose] Although previous studies have demonstrated several effects of sesamol on neurological diseases, its effects on ischemic stroke are unclear. We evaluated the direct effects of sesamol on infarcts and efficacy in terms of functional improvement in rats with transient middle cerebral artery occlusion (MCAO). [Subjects and Methods] Male Sprague Dawley rats (n = 30) were randomly divided into two groups: an MCAO with sesamol group and an MCAO group. MCAO was induced for 2 h, and sesamol was administered in the treatment group just after reperfusion. Infarct size was calculated 5 days after MCAO. Efficacy in function was assessed using a modified sticky-tape test (MST) and percent weight borne on the paretic leg during 5 days. [Results] Infarct volumes did not differ significantly between the two MCAO groups. The values of MST did not differ between the two MCAO groups. Based on the values of percent weight borne on the paretic leg, function of the hindlimb in the MCAO with sesamol group was significantly better than in the MCAO group throughout the experimental period. [Conclusion] These results demonstrate that sesamol induced functional improvements during 5 days after MCAO, and could be a useful addition to the therapeutic regimen for the treatment of ischemic stroke.