Walk Locomotion Kinematic Changes in a Model of Penetrating Hippocampal Injury in Male/Female Mice and Rats.

Traumatic brain injury has been the leading cause of mortality and morbidity in human beings. One of the most susceptible structures to this damage is the hippocampus due to cellular and synaptic loss and impaired hippocampal connectivity to the brain, brain stem, and spinal cord. Thus, hippocampal damage in rodents using a stereotaxic device could be an adequate method to study a precise lesion from CA1 to the dentate gyrus structures. We studied male and female rats and mice, analyzing hindlimb locomotion kinematics changes to compare the locomotion kinematics using the same methodology in rodents. We measure (1) the vertical hindlimb metatarsus, ankle, and knee joint vertical displacements (VD) and (2) the factor of dissimilarity (DF). The VD in intact rats in metatarsus, ankle, and knee joints differs from that in intact mice in similar joints. In rats, the vertical displacement through the step cycle changed in the left and right metatarsus, ankle, and knee joints compared to the intact group versus the lesioned group. More subtle changes were also observed in mice. DF demonstrates contrasting results when studying locomotion kinematics of mice or rats and sex-dependent differences. Thus, a precise lesion in a rodent's hippocampal structure discloses some hindlimb locomotion changes related to species and sex. Thus, we only have a qualitative comparison between murine species. In order to make a comparison with other species, we should standardize the model.

Locomotion Outcome Improvement in Mice with Glioblastoma Multiforme after Treatment with Anastrozole.

Glioblastoma Multiforme (GBM) is a tumor that infiltrates several brain structures. GBM is associated with abnormal motor activities resulting in impaired mobility, producing a loss of functional motor independence. We used a GBM xenograft implanted in the striatum to analyze the changes in Y (vertical) and X (horizontal) axis displacement of the metatarsus, ankle, and knee. We analyzed the steps dissimilarity factor between control and GBM mice with and without anastrozole. The body weight of the untreated animals decreased compared to treated mice. Anastrozole reduced the malignant cells and decreased GPR30 and ERα receptor expression. In addition, we observed a partial recovery in metatarsus and knee joint displacement (dissimilarity factor). The vertical axis displacement of the GBM+anastrozole group showed a difference in the right metatarsus, right knee, and left ankle compared to the GBM group. In the horizontal axis displacement of the right metatarsus, ankle, and knee, the GBM+anastrozole group exhibited a difference at the last third of the step cycle compared to the GBM group. Thus, anastrozole partially modified joint displacement. The dissimilarity factor and the vertical and horizontal displacements study will be of interest in GBM patients with locomotion alterations. Hindlimb displacement and gait locomotion analysis could be a valuable methodological tool in experimental and clinical studies to help diagnose locomotive deficits related to GBM.

Neonatal Mice Spinal Cord Interneurons Send Axons through the Dorsal Roots.

Spontaneous interneuron activity plays a critical role in developing neuronal networks. Discharges conducted antidromically along the dorsal root (DR) precede those from the ventral root's (VR) motoneurons. This work studied whether spinal interneurons project axons into the neonate's dorsal roots. Experiments were carried out in postnatal Swiss-Webster mice. We utilized a staining technique and found that interneurons in the spinal cord's dorsal horn send axons through the dorsal roots. In vitro electrophysiological recordings showed antidromic action potentials (dorsal root reflex; DRR) produced by depolarizing the primary afferent terminals. These reflexes appeared by stimulating the adjacent dorsal roots. We found that bicuculline reduced the DRR evoked by L5 dorsal root stimulation when recording from the L4 dorsal root. Simultaneously, the monosynaptic reflex (MR) in the L5 ventral root was not affected; nevertheless, a long-lasting after-discharge appeared. The addition of 2-amino-5 phosphonovaleric acid (AP5), an NMDA receptor antagonist, abolished the MR without changing the after-discharge. The absence of DRR and MR facilitated single action potentials in the dorsal and ventral roots that persisted even in low Ca2+ concentrations. The results suggest that firing interneurons could send their axons through the dorsal roots. These interneurons could activate motoneurons producing individual spikes recorded in the ventral roots. Identifying these interneurons and the persistence of their neuronal connectivity in adulthood remains to be established.

Proliferation and apoptosis regulation by G protein-coupled estrogen receptor in glioblastoma C6 cells.

Glioblastoma is the most frequent primary tumor in the human brain. Glioblastoma cells express aromatase and the classic estrogen receptors ERα and ERß and can produce estrogens that promote tumor growth. The membrane G protein-coupled estrogen receptor (GPER) also plays a significant role in numerous types of cancer; its participation in glioblastoma tumor development is not entirely known. The present study investigated the effect of the agonists [17ß-estradiol (E2) and G1] and antagonist (G15) of GPER on proliferation and apoptosis of C6 glioblastoma cells. GPER expression was evaluated by immunofluorescence, western blotting and reverse transcription-quantitative PCR. Cell proliferation was determined using Ki67 immunopositivity. Cell viability was examined using the MTT assay and apoptosis using caspase-3 immunostaining and ELISA. C6 cells express GPER, and the immunopositivity increased after exposure to E2, G1, or their combination. GPER protein expression increased after treatment with E2 combined with G1. However, GPER mRNA expression decreased in treated cells compared with control. The percentage of Ki67 immunopositive C6 cells increased under the effect of E2 in combination with G1 or G1 alone. G15 significantly reduced Ki67 immunopositivity. Pearson's correlation analysis revealed a positive relationship between GPER and Ki67 immunopositivity across the study conditions. Additionally, the MTT assay showed a significant reduction in C6 cell viability after G15 treatment, alone or in combination with G1. The exposure to G15 increased the percentage of caspase-3 immunopositivity cells and caspase-3 levels. Pearson's correlation analysis demonstrated a negative correlation between GPER and caspase-3 immunopositivity across the study conditions. Glioblastoma C6 cells express GPER, and this receptor modulates cell proliferation and apoptosis. The GPER agonists E2 and G1 favored cell proliferation; meanwhile, the antagonist G15 reduced cell proliferation, viability and favored apoptosis. Therefore, GPER may be used as a biomarker of glioblastoma and as a target to develop new therapeutic strategies for glioblastoma treatment.

Toxoplasmosis Is More Frequent in Schizophrenia Patients Than in the General Population in Mexico and Is Not Associated with More Severe Course of Schizophrenia Measured with the Brief Psychiatric Rating Scale.

Toxoplasmosis is a disease, which was discovered in 1908, caused by the intracellular parasite Toxoplasma gondii. T. gondii infects neuronal, glial, and muscle cells, and chronic infections are characterized by the presence of cysts, in the brain and muscle cells, formed by bradyzoites. T. gondii is capable of synthesizing L-DOPA, a precursor of dopamine. Dopamine is a neurotransmitter that is key in the etiology of neuropsychological disorders such as schizophrenia. Previous studies have shown high levels of IgG Toxoplasma antibodies in schizophrenia patients. Many published studies show that the prevalence of toxoplasmosis is higher in schizophrenia patients. In this study, we aimed to identify the prevalence of Toxoplasma infection in patients with schizophrenia and the relationships between, sociodemographic factors and the Brief Psychiatric Rating Scale. A total of 27 schizophrenic patients were included and IgG anti-T. gondii was determined in serum samples by ELISA. The Brief Psychiatric Rating Scale, sociodemographic factors were associated with seropositivity. We found that the prevalence of Toxoplasma antibodies was 51.7%. In the Brief Psychiatric Rating Scale, statistical significant association (p = 0.024) was found in Item 13 which is related to motor retardation, however, the association turned non-significant after of correction for multiple tests or after of analyzed with a logistic regression p = 0.059, odds ratio (OR) = 2.316 with a 95% confidence interval [0.970 to 5.532]. Other association was not found between toxoplasmosis and others factors. The prevalence of toxoplasmosis on our population under study was significantly higher than that reported by general population or other group of Mexican schizophrenia patients.

Kinematic Changes in a Mouse Model of Penetrating Hippocampal Injury and Their Recovery After Intranasal Administration of Endometrial Mesenchymal Stem Cell-Derived Extracellular Vesicles.

Locomotion speed changes appear following hippocampal injury. We used a hippocampal penetrating brain injury mouse model to analyze other kinematic changes. We found a significant decrease in locomotion speed in both open-field and tunnel walk tests. We described a new quantitative method that allows us to analyze and compare the displacement curves between mice steps. In the tunnel walk, we marked mice with indelible ink on the knee, ankle, and metatarsus of the left and right hindlimbs to evaluate both in every step. Animals with hippocampal damage exhibit slower locomotion speed in both hindlimbs. In contrast, in the cortical injured group, we observed significant speed decrease only in the right hindlimb. We found changes in the displacement patterns after hippocampal injury. Mesenchymal stem cell-derived extracellular vesicles had been used for the treatment of several diseases in animal models. Here, we evaluated the effects of intranasal administration of endometrial mesenchymal stem cell-derived extracellular vesicles on the outcome after the hippocampal injury. We report the presence of vascular endothelial growth factor, granulocyte-macrophage colony-stimulating factor, and interleukin 6 in these vesicles. We observed locomotion speed and displacement pattern preservation in mice after vesicle treatment. These mice had lower pyknotic cells percentage and a smaller damaged area in comparison with the nontreated group, probably due to angiogenesis, wound repair, and inflammation decrease. Our results build up on the evidence of the hippocampal role in walk control and suggest that the extracellular vesicles could confer neuroprotection to the damaged hippocampus.

Fictive Scratching Patterns in Brain Cortex-Ablated, Midcollicular Decerebrate, and Spinal Cats.

Background: The spinal cord's central pattern generators (CPGs) have been explained by the symmetrical half-center hypothesis, the bursts generator, computational models, and more recently by connectome circuits. Asymmetrical models, at odds with the half-center paradigm, are composed of extensor and flexor CPG modules. Other models include not only flexor and extensor motoneurons but also motoneuron pools controlling biarticular muscles. It is unknown whether a preferred model can explain some particularities that fictive scratching (FS) in the cat presents. The first aim of this study was to investigate FS patterns considering the aiming and the rhythmic periods, and second, to examine the effects of serotonin (5HT) on and segmental inputs to FS. Methods: The experiments were carried out first in brain cortex-ablated cats (BCAC), then spinalized (SC), and for the midcollicular (MCC) preparation. Subjects were immobilized and the peripheral nerves were used to elicit the Monosynaptic reflex (MR), to modify the scratching patterns and for electroneurogram recordings. Results: In BCAC, FS was produced by pinna stimulation and, in some cases, by serotonin. The scratching aiming phase (AP) initiates with the activation of either flexor or extensor motoneurons. Serotonin application during the AP produced simultaneous extensor and flexor bursts. Furthermore, WAY 100635 (5HT1A antagonist) produced a brief burst in the tibialis anterior (TA) nerve, followed by a reduction in its electroneurogram (ENG), while the soleus ENG remained silent. In SC, rhythmic phase (RP) activity was recorded in the soleus motoneurons. Serotonin or WAY produced FS bouts. The electrical stimulation of Ia afferent fibers produced heteronymous MRes waxing and waning during the scratch cycle. In MCC, FS began with flexor activity. Electrical stimulation of either deep peroneus (DP) or superficial peroneus (SP) nerves increased the duration of the TA electroneurogram. Medial gastrocnemius (MG) stretching or MG nerve electrical stimulation produced a reduction in the TA electroneurogram and an initial MG extensor burst. MRes waxed and waned during the scratch cycle. Conclusion: Descending pathways and segmental afferent fibers, as well as 5-HT and WAY, can change the FS pattern. To our understanding, the half-center hypothesis is the most suitable for explaining the AP in MCC.

Challenges and Improvements of Developing an Ischemia Mouse Model Through Bilateral Common Carotid Artery Occlusion.

Brain ischemia is one of the principal causes of death and disability worldwide in which prevention or an effective treatment does not exist. In order to develop successful treatments, an adequate and useful ischemia model is essential. Transient global cerebral ischemia is one of the most interesting pathological conditions in stroke studies because of the observed degeneration of forebrain and delayed neuronal cell death in selective vulnerable regions such as hippocampus. Transient occlusion of both common carotid arteries is the most convenient model to induce tGCI. Although there are effective rat and gerbil models using this method, the induction of a reproducible and reliable injury after global ischemia in mouse has presented higher variations, mainly because of its size and the necessary monitoring skills in order to accomplish homogeneous and reproducible results. Further, great variability among cerebral vasculature and susceptibility of the different strains and sub-strains is observed. In recent years, some modifications have been made to the model in order to normalize the heterogenic effects. Analysis of posterior communicating artery patency has been proposed as an exclusion parameter due to the direct relationship reported with the reduction of cerebral blood flow. Another method used to significantly reduce blood flow is the induction of hypotension with isoflurane. Each protocol produces distinct injury outcomes. Further improvements are needed to attain a general, simpler, reproducible and globally accepted model that allows comparisons between research groups, progress in understanding ischemia and the consequent development of therapeutic alternatives for ischemic injury.

Kinematic Locomotion Changes in C57BL/6 Mice Infected with Toxoplasma Strain ME49.

Chronic infection with the intracellular parasite Toxoplasma gondii produces an accumulation of cysts in the brain and muscle, causing tissue damage. The cysts in the brain motor regions affect some kinematic locomotion parameters in the host. To localize the brain cysts from Toxoplasma gondii and study the changes in kinematic locomotion in C57BL/6 mice. Female adult C57BL/6 mice were infected orally with 30 ME-49 Toxoplasma gondii cysts. An uninfected group (n = 7) and two infected groups, examined 15 and 40 days postinfection, were used for this study. To evaluate kinematic locomotion, the mice were marked with indelible ink on the iliac crest, hip, knee, ankle, and phalangeal metatarsus of the left and right hindlimbs. At least three recordings were carried out to obtain videos of the left and right hindlimbs. Mice were video recorded at 90 fps at a resolution of 640 × 480 pixels while walking freely in a transparent Plexiglass tunnel. We measured the hindlimb pendular movement and the hindlimb transfer [linear displacement] curves for each step and evaluated them statistically with Fréchet dissimilarity tests. Afterward, the mice were sacrificed, and the brain, heart, skeletal muscle, lung, liver, and kidney were obtained. The different tissues were stained with hematoxylin and eosin for analysis with optical microscopy. Topographic localization of the cysts was made using bregma coordinates for the mouse brain. The cysts were distributed in several brain regions. In one mouse, cyst accumulation occurred in the hippocampus, coinciding with an alteration in foot displacement. The step length was different among the different studied groups.

Locomotion in intact and in brain cortex-ablated cats.

The current decerebration procedures discard the role of the thalamus in the motor control and decortication only rules out the brain cortex part, leaving a gap between the brain cortex and the subthalamic motor regions. In here we define a new preparation denominated Brain Cortex-Ablated Cat (BCAC), in which the frontal and parietal brain cortices as well as the central white matter beneath them were removed, this decerebration process may be considered as suprathalamic, since the thalamus remained intact. To characterize this preparation cat hindlimb electromyograms (EMG), kinematics and cutaneous reflexes (CR) produced by electrical stimulation of sural (SU) or saphenous (SAPH) nerves were analyzed during locomotion in intact and in BCAC. In cortex-ablated cats compared to intact cats, the hindlimb EMG amplitude was increased in the flexors, whereas in most extensors the amplitude was decreased. Bifunctional muscle EMGs presented complex and speed-dependent amplitude changes. In intact cats CR produced an inhibition of extensors, as well as excitation and inhibition of flexors, and a complex pattern of withdrawal responses in bifunctional muscles. The same stimuli applied to BCAC produced no detectable responses, but in some cats cutaneous reflexes produced by electrical stimulation of saphenous nerve reappeared when the locomotion speed increased. In BCAC, EMG and kinematic changes, as well as the absence of CR, imply that for this cat preparation there is a partial compensation due to the subcortical locomotor apparatus generating close to normal locomotion.

Tamoxifen Promotes Axonal Preservation and Gait Locomotion Recovery after Spinal Cord Injury in Cats.

We performed experiments in cats with a spinal cord penetrating hemisection at T13-L1 level, with and without tamoxifen treatment. The results showed that the numbers of the ipsilateral and contralateral ventral horn neurons were reduced to less than half in the nontreated animals compared with the treated ones. Also, axons myelin sheet was preserved to almost normal values in treated cats. On the contrary, in the untreated animals, their myelin sheet was reduced to 28% at 30 days after injury (DAI), in both the ipsilateral and contralateral regions of the spinal cord. Additionally, we made hindlimb kinematics experiments to study the effects of tamoxifen on cat locomotion after the injury: at 4, 16, and 30 DAI. We observed that the ipsilateral hindlimb angular displacement (AD) of the pendulum-like movements (PLM) during gait locomotion was recovered to almost normal values in treated cats. Contralateral PLM acquired similar values to those obtained in intact cats. At 4 DAI, untreated animals showed a compensatory increment of PLM occurring in the contralateral hindlimb, which was partially recovered at 30 DAI. Our findings indicate that tamoxifen exerts a neuroprotective effect and preserves or produces myelinated axons, which could benefit the locomotion recovery in injured cats.