Behavioral effects and neural changes induced by continuous and not continuous treadmill training, post bilateral cerebral ischemia in gerbils

Acupuncture and Electroacupuncture Effects of ST-36 (Zusanli) and SP-9 (Yinlingquan) on Motor Behavior in Ischemic Gerbils

Objective

Stroke is a leading cause of death and disability worldwide. To find ways to reduce behavioral disabilities, researchers study animal models. By targeting ST-36 (Zusanli) and SP-9 (Yinlingquan), this study investigated the effects of traditional acupuncture and electroacupuncture (EA) on motor behavior in gerbils following global cerebral ischemia.

Materials and Methods

Thirty-six male gerbils were randomly assigned to 6 groups (n = 6 in each): control (C); sham-surgical (S); ischemia (I); acupuncture (Ac); EA (Ea); and sham-EA (SEa). The animals were habituated in an activity cage (AC) 72 hours before surgery. After induction of global ischemia, the Ac, Ea, and SEa groups received bilateral stimulation at ST-36 and SP-9. In the Ea group, an alternating electrical current was used. The animals were tested in the AC 4 days after surgery, and the results were analyzed by Kruskal-Wallis, followed by Dunn's posthoc test.

Results

Statistical analysis revealed increased distance traveled and sensors triggered by the I, Ea, and SEa groups, compared to the C, Ac, and S groups. The animals' movement tracks had a similar pattern between the I and Ea groups, with increased exploration along the walls of the AC. Meanwhile, the Ac, S, and SEa groups explored the AC similarly to the C group.

Conclusions

These findings suggest that acupuncture may normalize motor behavior in gerbils with ischemia and could be a promising treatment for stroke-induced motor deficits.

Nonpharmacological Treatments for Hospitalized Patients with Stroke: A Nuanced Approach to Prescribing Early Activity

Stroke remains a leading cause of adult disability. To date, hyperacute revascularization procedures reach 5-10% of stroke patients even in high resource health systems. There is a limited time window for brain repair after stroke, and therefore, the activities such as prescribed exercise in the earliest period will likely have long-term significant consequences. Clinicians who provide care for hospitalized stroke patients make treatment decisions specific to activity often without guidelines to direct these prescriptions. This requires a balanced understanding of the available evidence for early post-stroke exercise and physiological principles after stroke that drive the safety of prescribed exercise. Here, we provide a summary of these relevant concepts, identify gaps, and recommend an approach to prescribing safe and meaningful activity for all patients with stroke. The population of thrombectomy-eligible stroke patients can be used as the exemplar for conceptualization.

Relationship between Neuronal Damage/Death and Astrogliosis in the Cerebral Motor Cortex of Gerbil Models of Mild and Severe Ischemia and Reperfusion Injury

Neuronal loss (death) occurs selectively in vulnerable brain regions after ischemic insults. Astrogliosis is accompanied by neuronal death. It can change the molecular expression and morphology of astrocytes following ischemic insults. However, little is known about cerebral ischemia and reperfusion injury that can variously lead to damage of astrocytes according to the degree of ischemic injury, which is related to neuronal damage/death. Thus, the purpose of this study was to examine the relationship between damage to cortical neurons and astrocytes using gerbil models of mild and severe transient forebrain ischemia induced by blocking the blood supply to the forebrain for five or 15 min. Significant ischemia tFI-induced neuronal death occurred in the deep layers (layers V and VI) of the motor cortex: neuronal death occurred earlier and more severely in gerbils with severe ischemia than in gerbils with mild ischemia. Distinct astrogliosis was detected in layers V and VI. It gradually increased with time after both ischemiae. The astrogliosis was significantly higher in severe ischemia than in mild ischemia. The ischemia-induced increase of glial fibrillary acidic protein (GFAP; a maker of astrocyte) expression in severe ischemia was significantly higher than that in mild ischemia. However, GFAP-immunoreactive astrocytes were apparently damaged two days after both ischemiae. At five days after ischemiae, astrocyte endfeet around capillary endothelial cells were severely ruptured. They were more severely ruptured by severe ischemia than by mild ischemia. However, the number of astrocytes stained with S100 was significantly higher in severe ischemia than in mild ischemia. These results indicate that the degree of astrogliosis, including the disruption (loss) of astrocyte endfeet following ischemia and reperfusion in the forebrain, might depend on the severity of ischemia and that the degree of ischemia-induced neuronal damage may be associated with the degree of astrogliosis.

The Organization of Somatostatin-Immunoreactive Cells in the Visual Cortex of the Gerbil

Somatostatin (SST) is widely expressed in the brain and plays various, vital roles involved in neuromodulation. The purpose of this study is to characterize the organization of SST neurons in the Mongolian gerbil visual cortex (VC) using immunocytochemistry, quantitative analysis, and confocal microscopy. As a diurnal animal, the Mongolian gerbil provides us with a different perspective to other commonly used nocturnal rodent models. In this study, SST neurons were located in all layers of the VC except in layer I; they were most common in layer V. Most SST neurons were multipolar round/oval or stellate cells. No pyramidal neurons were found. Moreover, 2-color immunofluorescence revealed that only 33.50%, 24.05%, 16.73%, 0%, and 64.57% of SST neurons contained gamma-aminobutyric acid, calbindin-D28K, calretinin, parvalbumin, and calcium/calmodulin-dependent protein kinase II, respectively. In contrast, neuropeptide Y and nitric oxide synthase were abundantly expressed, with 80.07% and 75.41% in SST neurons, respectively. Our immunocytochemical analyses of SST with D₁ and D₂ dopamine receptors and choline acetyltransferase, α₇ and β₂ nicotinic acetylcholine receptors suggest that dopaminergic and cholinergic fibers contact some SST neurons. The results showed some distinguishable features of SST neurons and provided some insight into their afferent circuitry in the gerbil VC. These findings may support future studies investigating the role of SST neurons in visual processing.

Aerobic exercise attenuates neurodegeneration and promotes functional recovery - Why it matters for neurorehabilitation & neural repair

Aerobic exercise facilitates optimal neurological function and exerts beneficial effects in neurologic injuries. Both animal and clinical studies have shown that aerobic exercise reduces brain lesion volume and improves multiple aspects of cognition and motor function after stroke. Studies using animal models have proposed a wide range of potential molecular mechanisms that underlie the neurological benefits of aerobic exercise. Furthermore, additional exercise parameters, including time of initiation, exercise dosage (exercise duration and intensity), and treatment modality are also critical for clinical application, as identifying the optimal combination of parameters will afford patients with maximal functional gains. To clarify these issues, the current review summarizes the known neurological benefits of aerobic exercise under both physiological and pathological conditions and then considers the molecular mechanisms underlying these benefits in the contexts of stroke-like focal cerebral ischemia and cardiac arrest-induced global cerebral ischemia. In addition, we explore the key roles of exercise parameters on the extent of aerobic exercise-induced neurological benefits to elucidate the optimal combination for aerobic exercise intervention. Finally, the current challenges for aerobic exercise implementation after stroke are discussed.

Continuous and not continuous 2-week treadmill training enhances the performance in the passive avoidance test in ischemic gerbils

This study aims to investigate the frequency and total duration effects of the 2-week treadmill training after experimental ischemic stroke in the passive avoidance test. We performed bilateral occlusion of common external carotid arteries, for five minutes, in Mongolian gerbils. The training groups were: continuous training for twelve consecutive days or not continuous training for six non-consecutive days. The groups remained in the treadmill for 15min, with the speed set at 10m/min, and the training started 24h after the stroke. In the Shuttle Box, each animal had ten trials during the Learning Session (LS), which occurred 24h before the stroke. The Retention Test (RT) occurred 24h after the stroke and started on the second, third, seventh and twelfth day after LS. After the experiments, the brains were perfused, and coronal sections of the CA1 area of the hippocampus were cut and stained with hematoxylin and eosin. ANOVA on Ranks was used for Behavioral data analysis and morphological data by percentage. Ischemic training groups showed preservation in neuron density in the CA1 area of the hippocampus, when compared to the control groups. Animals subjected to continuous training, showed a higher latency in the RT when compared to ischemic animals in both weeks [(2nd, H=39.81; P<0.05), (3rd, H=38.08; P<0.05), (7th, H=44.17; P<0.05), and (12th, H=39.55; P<0.05). Animals in the not continuous training showed higher latency in the RT, in the second week only [(2nd, H=39.81; P<0.05), (3rd, H=38.08; P<0.05), (7th, H=44.17; P<0.05), and (12th, H=39.55; P<0.05). These findings suggest that improvement of memory after stroke after treadmill training is dependent on the frequency and total duration of training.

Comparing the Organs and Vasculature of the Head and Neck in Five Murine Species

BACKGROUND/AIM

The purpose of the present study was to delineate the cervical and facial vascular and associated anatomy in five murine species, and compare them for optimal use in research studies focused on understanding the pathology and treatment of diseases in humans.

MATERIALS AND METHODS

The specific adult male animals examined were mice (C57BL/6J), rats (F344), mongolian gerbils (Merionesunguiculatus), hamsters (Syrian), and guinea pigs (Hartley). To stain the vasculature and organs, of the face and neck, each animal was systemically perfused using the vital stain, Trypan Blue. Following this step, the detailed anatomy of the head and neck could be easily visualized in all species.

RESULTS

Unique morphological characteristics were demonstrated by comparing the five species, including symmetry of the common carotid origin bilaterally in the Mongolian Gerbil, a large submandibular gland in the hamster and an enlarged buccal branch in the Guinea Pig. In reviewing the anatomical details, this staining technique proves superior for direct surgical visualization and identification.

CONCLUSION

The anatomical details provided through these five species atlas will help experimental researchers in the future to select the most appropriate animal model for specific laboratory studies aimed to improve our understanding and treatment of diseases in patients.

Neuroprotection and reduced gliosis by pre- and post-treatments of hydroquinone in a gerbil model of transient cerebral ischemia

Hydroquinone (HQ), a major metabolite of benzene, exists in many plant-derived food and products. Although many studies have addressed biological properties of HQ including the regulation of immune responses and antioxidant activity, neuroprotective effects of HQ following ischemic insults have not yet been considered. Therefore, in this study, we examined neuroprotective effects of HQ against ischemic damage in the gerbil hippocampal cornu ammonis 1 (CA1) region following 5 min of transient cerebral ischemia. We found that pre- and post-treatments with 50 and 100 mg/kg of HQ protected CA1 pyramidal neurons from ischemic insult. Especially, pre- and post-treatments with 100 mg/kg of HQ showed strong neuroprotective effects against ischemic damage. In addition, pre- and post-treatments with 100 mg/kg of HQ significantly attenuated activations of astrocytes and microglia in the ischemic CA1 region compared to the vehicle-treated-ischemia-operated group. Briefly, these results show that pre- and post-treatments with HQ can protect neurons from transient cerebral ischemia and strongly attenuate ischemia-induced glial activation in the hippocampal CA1 region, and indicate that HQ can be used for both prevention and therapy of ischemic injury.

Aerobic exercise combined with huwentoxin-I mitigates chronic cerebral ischemia injury

Ca²⁺ channel blockers have been shown to protect neurons from ischemia, and aerobic exercise has significant protective effects on a variety of chronic diseases. The present study injected huwentoxin-I (HWTX-I), a spider peptide toxin that blocks Ca²⁺ channels, into the caudal vein of a chronic cerebral ischemia mouse model, once every 2 days, for a total of 15 injections. During this time, a subgroup of mice was subjected to treadmill exercise for 5 weeks. Results showed amelioration of cortical injury and improved neurological function in mice with chronic cerebral ischemia in the HWTX-I + aerobic exercise group. The combined effects of HWTX-I and exercise were superior to HWTX-I or aerobic exercise alone. HWTX-I effectively activated the Notch signal transduction pathway in brain tissue. Aerobic exercise up-regulated synaptophysin mRNA expression. These results demonstrated that aerobic exercise, in combination with HWTX-I, effectively relieved neuronal injury induced by chronic cerebral ischemia via the Notch signaling pathway and promoting synaptic regeneration.