Guilherme Bertolino

Neuropathology and behavioral impairments after three types of global ischemia surgery in Meriones unguiculatus: Evidence in motor cortex, hippocampal CA1 region and the neostriatum

The effects of three types of global ischemia by occlusion of carotid artery on motor and exploratory behaviors of Gerbils were evaluated by the Activity Cage and Rota rod tests. Animals were divided based on two surgical criteria: unilateral (UNI) or bilateral (BIL) carotid occlusion, with (REP) or without (OCL) reperfusion; and their behavior was evaluated on the fourth (4) or sixth (6) day. There was reduction of cell number in striatum, motor cortex M1 area, and hippocampal CA1 area in all groups in comparison to control animals. For M1 area and striatum, the largest reduction was observed in UNI6, UNI4, and BIL4 groups. Neuronal loss was also observed in CA1 area of BIL4 rodents. There was a decrease in crossings and rearings in all groups in activity cage test, compared to control. Reperfusion, unilateral and bilateral occlusion groups showed decrease in crossings. Only the BIL4 showed a decrease of rearing. In the Rota rod test, except the UNIOCL6, the groups showed a decrease in the balance in comparison to control. Both groups with REP4 showed a major decrease in balance. These findings suggest that both unilateral and bilateral carotid occlusions with reperfusion produce impairments of motor and exploratory behavior.

Influence of treadmill training on motor performance and organization of exploratory behavior in Meriones unguiculatus with unilateral ischemic stroke: histological correlates in hippocampal CA1 region and the neostriatum.

This study examined the effects of motor stimulation via treadmill on the behavior of male gerbils after external carotid ischemic brain lesion. The animals were assigned to five groups; ischemic with no stimulation (SIG), ischemic with stimulation (SIG 12/24/48/72h after surgery), non-ischemic with no stimulation (CC), non-ischemic with stimulation (CE) and sham, surgery without occlusion with no stimulation (SH). All the animals were tested in the open-field (OF) and rotarod (RR), 4 days after surgery in order to evaluate exploratory behaviors and motor performance. Data were submitted to one-way variance (ANOVA) and Dunnetts post hoc comparisons. SIG and SIG 12 groups showed a significant decrease in motor response (crossing) when compared to the control group (CC) (F=20.65, P<0.05) in the OF. SIG 12 group showed an increase in grooming behavior (F=23.136, P<0.05) and all ischemia groups (SIG, SIG12/24/48/72) spent less time on the RR (F=10.40, P<0.05), when compared to the control group (CC). Histological analyses show extensive lesions in the hippocampus and neostriatum for all groups with ischemia (SIG, SIG12/24/48/72), which are structures involved in the organization of motor behavior. Interestingly, the most pronounced damage was found in animals submitted to motor stimulation 12h after ischemia which can be correlated to the increased number of grooming behavior showed by them in the OF. These findings suggest that motor stimulation through treadmill training improve motor behavior after ischemia, except when it starts 12h after surgery.

Neuropathology and behavioral impairments after bilateral global ischemia surgery and exposure to static magnetic field: Evidence in the motor cortex, the hippocampal CA1 region and the neostriatum

Abstract Purpose: To evaluate the effects of continuous magnetic field stimulation after four days of global encephalic ischemia on motor behavior and brain morphology in gerbils. Material and methods: Sixty Mongolian gerbils were divided into five groups: Control (CG), sham (SG), ischemia (IG), ischemia north (INPG) and south (ISPG) pole. Experimental animals underwent bilateral occlusion of the carotid artery. In groups with magnetic stimulation, a 3200 gauss magnet was fixed to the skull. After brain perfusion, coronal sections of the striatum, motor cortex (M1) and CA1 area of the hippocampus (CA1) were cut and stained with hematoxylin and eosin. Results: In the open field test (OF) we observed an increase in crossing in the IG compared to the CG, INPG and ISPG (F = 20.19), and a reduction in the time spent on the Rota-rod test (RR) with the IG compared to CG, IPNG and ISPG (F = 17.59). Morphometric analysis revealed a reduction in the density of the neurons in the CA1, in the number of M1 and striatal neurons in the IG compared to the CG, INPG and ISPG. Conclusion: Our results demonstrate a potential therapeutic application of static magnetic fields for the preservation of motor behavior and neurons in regions analyzed after global cerebral ischemia.

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

This study aims to investigate the effects of treadmill training and the possible influences of the start, regularity, and duration after experimental ischemic stroke. We performed bilateral occlusion of both the carotid arteries for 5 min in Mongolian gerbils. The training groups were: continuous training for 5 consecutive days or not continuous training for 3 non-consecutive days. The groups remained in the treadmill for 15 min, and the training started 12 or 24h after the stroke. In the activity cage (AC), behaviors of crossing and distance traveled were registered. The forced motor behavior was analyzed by a Rota Rod test. After the experiments, the brains were perfused, and coronal sections of the striatum, motor cortex M1, and CA1 area of the hippocampus were cut and stained with hematoxylin and eosin. Behavioral and morphological data analysis was performed by an ANOVA and MANCOVA. Results showed an increased density of neurons in the CA1 area of the hippocampus, motor cortex M1, and the striatum in ischemic training groups compared to the not training ischemic groups. Animals subjected to continuous training that started 24h after ischemia showed a satisfactory behavior in the AC and a higher number of striatal neurons when compared to ischemic animals. The animals in the not continuous training started 12h after the stroke showed an unsatisfactory performance in the AC and Rota Rod. These findings suggest that early training and not continuous training are inadequate for motor behavior improvement after stroke.

Neuropathology and behavioral impairments in Wistar rats with a 6-OHDA lesion in the substantia nigra compacta and exposure to a static magnetic field

Studies have sought to assess various potential neuroprotective therapeutics in Parkinsons disease. The aim of this study was to evaluate the effects of static magnetic field stimulation 14 days after a 6-Hydroxydopamine (6-OHDA) substantia nigra compacta (SNc) lesion on motor behavior, as assessed by the rotarod (RR) test and brain tissue morphology. Forty male Wistar rats were used and were divided into five groups: control group, sham group (SG), lesion group (LG), lesion north pole group (LNPG) and lesion south pole group (LSPG). In groups with magnetic stimulation, a 3200-gauss magnet was fixed to the skull. After the experiments, the animals were anesthetized for brain perfusion. Coronal sections of the SNc were stained with Nissl. The RR test showed a decrease in the time spent on the apparatus in the LG compared with all groups. The LNPG and LSPG had significant increases in the time spent when compared to the LG. A morphometric analysis revealed a significant reduction in the number of neurons in the LG, LNPG and LSPG in relation to the SG. There were a higher number of neurons in the LNPG and LSPG than the LG, and a higher number of neurons in the LSPG than the LNPG. We observed that the LG, LNPG and LSPG showed a higher number of glial cells than the SG, and the LNPG and LSPG showed a lower number of glial cells than the LG. Our results demonstrate a potential therapeutic use of static magnetic fields for the preservation of motor behavior and brain morphology in the SNc after 14 days with 6-OHDA lesion.

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.