RESUMO Objetivo Analisar os efeitos dos treinamentos aeróbios e anaeróbios em diferentes ergômetros na hipertrofia muscular e cardíaca de ratos. Métodos Os animais foram separados nos grupos controle (C), treinamento aeróbio em natação (ATW), treinamento resistido em meio aquático (RTW), treinamento aeróbio em esteira rolante (ATT) e treinamento resistido em escalada (RTC). Os protocolos de treinamento foram realizados por 4 semanas, 3 x/semana. Foram mensurados a área de secção transversa (CSA) das células do músculo gastrocnêmio e as áreas dos cardiomiócitos. Resultados Nas fibras de contração rápida houve aumento da CSA dos grupos RTW e RTC em relação aos grupos ATW (p<0,01 e p<0,01) e ATT (p<0,01 e p<0,01). Nas fibras de contração lenta os grupos ATW e ATT demonstraram menor CSA comparado aos grupos RTW (p=0,03 e p<0,00) e RTC (p<0,01 e p<0,01). Nos cardiomiócitos houve aumento da área dos grupos RTW e RTC em comparação com os grupos C (p<0,01 e p<0,01), ATW (p=0,02 e p<0,01) e ATT (p<0,01 e p<0,01). Conclusão Os treinamentos anaeróbios promoveram hipertrofia nas fibras de contração rápida e nos cardiomiócitos. Nível de Evidência V; Estudo experimental em animais.

ABSTRACT Objective Analyze the effects of aerobic and anaerobic training on different ergometers on muscle and cardiac hypertrophy in rats. Methods The animals were separated into the following groups: Control (C), Aerobic Training in Water (ATW), Resistance Training in Water (RTW), Aerobic Training on Treadmill (ATT), and Resistance Training in Climbing (RTC). All training protocols were carried out for 4 weeks, 3 times/week. The cross-sectional area (CSA) of the gastrocnemius muscle cells and the areas of the cardiomyocytes were measured. Results In the fast-twitch fibers, there was an increase in CSA in the RTW and RTC groups compared to the ATW (p<0.01 and p<0.01) and ATT groups (p<0.01 and p<0.01). In the slow-twitch fibers, the ATW and ATT groups demonstrated a lower CSA compared to the RTW (p=0.03 and p<0.00) and RTC groups (p<0.01 and p<0.01). In the cardiomyocytes, there was an increase in the area of the RTW and RTC groups compared to groups C (p<0.01; p<0.01), ATW (p=0.02; p<0.01), and ATT (p<0.01; p<0.01). Conclusion The anaerobic training effectively promotes hypertrophy in the fast-twitch fibers and the cardiomyocytes. Level of Evidence V; Animal experimental study.

SUMMARY: Repeated stress is a risk factor for memory impairment and neurological abnormalities in both humans and animals. We sought to investigate the extent of (i) brain tissue injury; (ii) nitrosative and oxidative stress in brain tissue homogenates; (iii) apoptotic and survival biomarkers in brain tissue homogenates; and (iv) immobility and climbing abilities, induced over a period of three weeks by chronic unpredictable stress (CUS). Wistar rats were either left untreated (Control group) or exposed to a variety of unpredictable stressors daily before being sacrificed after 3 weeks (model group). Assessment of depression-like behavior was performed and animals were then culled and harvested brain tissues were stained with basic histological staining and examined under light microscopy. In addition, brain tissue homogenates were prepared and assayed for these parameters; inducible nitric oxide synthase (iNOS), malondialdehyde (MDA), superoxide dismutase (SOD), caspase-3, and B-cell lymphoma 2 (Bcl-2). Histology images showed CUS induced profound damage to the cerebral cortex as demonstrated by severe neuronal damage with shrunken cells, disrupted atrophic nuclei, perineuronal vacuolation and swollen glial cells. CUS also significantly (p<0.05) induced iNOS, MDA, and caspase-3, whereas SOD and Bcl-2 brain tissue levels were inhibited by CUS. In addition, data from the depression-like behavior, forced swimming test showed significant (p<0.05) increase in animal immobility and decrease in climbing ability in the model group of rats. Thus, here we demonstrated a reliable rat model of chronic stress-induced brain injury, which can further be used to investigate beneficial drugs or agents used for a period of three weeks to protect against CUS-induced brain damage.

RESUMEN: El estrés crónico es un factor de riesgo para el deterioro de la memoria y las anomalías neurológicas tanto en humanos como en animales. Intentamos investigar el alcance de lesión del tejido cerebral; (ii) estrés nitrosativo y oxidativo en homogeneizados de tejido cerebral; (iii) biomarcadores apoptóticos y de supervivencia en homogeneizados de tejido cerebral; y (iv) inmovilidad y habilidades de escalada, inducidas durante un período de tres semanas por estrés crónico impredecible (ECI). Se dejaron sin tratamiento (grupo control) ratas Wistar, o se expusieron a una variedad de factores estresantes impredecibles diariamente antes de ser sacrificadas después de 3 semanas (grupo modelo). Se realizó una evaluación del comportamiento similar a la depresión y luego se sacrificaron los animales y se tiñeron los tejidos cerebrales con tinción histológica básica y se examinaron con microscopía óptica. Además, se prepararon homogeneizados de tejido cerebral y se analizaron los siguientes parámetros; óxido nítrico sintasa inducible (iNOS), malondialdehído (MDA), superóxido dismutasa (SOD), caspasa- 3 y linfoma de células B 2 (Bcl-2). Las imágenes histológicas mostraron que el CUS indujo un daño profundo en la corteza cerebral como lo demuestra el daño neuronal severo con células encogidas, núcleos atróficos alterados, vacuolación perineuronal y células gliales inflamadas. ECI también indujo significativamente (p <0,05) iNOS, MDA y caspase-3, mientras que los niveles de tejido cerebral SOD y Bcl-2 fueron inhibidos por ECI. Además, los datos del comportamiento similar a la de- presión, la prueba de natación forzada mostró un aumento significativo (p <0,05) en la inmovilidad animal y una disminución en la capacidad de escalada en el grupo modelo de ratas. Por lo tanto, aquí demostramos un modelo confiable de daño cerebral crónico en rata inducido por el estrés, que se puede utilizar para investigar medicamentos o agentes beneficiosos usados durante un período de tres semanas para proteger el daño cerebral inducido por ECI.

This paper reports the development of a three-channel automatic speed-matching climbing training system that could train three rats at the same time for rehabilitation after an ischemic stroke. An infrared (IR) remote sensor was installed at the end of each channel to monitor the real-time position of a climbing rat. This research was carried out in five stages: i) system design; ii) hardware circuit; iii) running speed control; iv) functional testing; and v) verification using an animal model of cerebral stroke. The rehabilitated group significantly outperformed the middle cerebral artery occlusion (MCAo) sedentary group in the rota-rod and inclined plate tests 21 days after a stroke. The rehabilitated group also had a cerebral infarction volume of 28.34±19.4%, far below 56.81±18.12% of the MCAo group 28 days after the stroke, validating the effectiveness of this training platform for stroke rehabilitation. The running speed of the climbing rehabilitation training platform was designed to adapt to the physical conditions of subjects, and overtraining injuries can be completely prevented accordingly.

Objective: To evaluate behavioral changes and brain-derived neurotrophic factor (BDNF) levels in rats subjected to ketamine administration (25 mg/kg) for 7 days. Method: Behavioral evaluation was undertaken at 1 and 6 hours after the last injection. Results: We observed hyperlocomotion 1 hour after the last injection and a decrease in locomotion after 6 hours. Immobility time was decreased and climbing time was increased 6 hours after the last injection. BDNF levels were decreased in the prefrontal cortex and amygdala when rats were killed 6 hours after the last injection, compared to the saline group and to rats killed 1 hour after the last injection. BDNF levels in the striatum were decreased in rats killed 6 hours after the last ketamine injection, and BDNF levels in the hippocampus were decreased in the groups that were killed 1 and 6 hours after the last injection. Conclusion: These results suggest that the effects of ketamine on behavior and BDNF levels are related to the time at which they were evaluated after administration of the drug.

Early weaning (EW) has proven to be a factor that decreases the animal's organic resistance against adverse conditions. Climbing in the forced swimming test (FST) is the active behavior that expresses the will of the rat to escape the stressful situation. A possible association between these two stress factors (EW and FST) has not yet been reported as a plausible model for the study of stress and depression. Under the working hypothesis that EW has possible adult behavioral correlates when associated with the FST, our objective was to analyze the levels of alteration in the active behaviors among groups. 20 Wistar rats (4 month old), were divided into two groups, the early weaned group (G1) and a control group (G2). The unit of analysis (tip), was defined as the number of intended escapes the animal performs in five minutes. We have found the differences stated by our hypothesis, comparing the frequency of scale or escape (tips), from a group with EW to a control group (15.8 ± 4.15 vs. 21.4 ± 4.14, p< 0.05). In turn, we found that, among females, the difference was significantly wider. The present study could elucidate under experimental conditions the effect that in adult behavior induces an alteration in the more primary bonds.

El destete temprano ha demostrado ser un factor que disminuye la resistencia orgánica de los animales contra condiciones adversas. La prueba de natación forzada se diseñó para experimentar la defensa del animal frente a un estímulo estresante. La conducta activa como el "escalar" se interpreta como una modelización experimental de voluntad o capacidad activa de escape. Bajo la hipótesis de que el destete temprano podría tener manifestaciones en la vida adulta relacionadas con la defensa frente al estrés, nuestro objetivo fue analizar la conducta de "escalado" o escape, durante una prueba de natación forzada, en animales adultos que habían sido destetados precozmente. Se utilizaron 20 ratas Wistar (4 meses de edad), divididas en dos grupos: G1 con destete temprano y G2 control. La unidad de análisis o "tip", se refirió a la cantidad de veces que el animal presentó la conducta de escape a lo largo de 5 minutos. Se hallaron diferencias estadísticamente significativas entre los tips de G1 y G2 (15,8 ± 4,15 contra 21,4 ± 4,14, p< 0,05). Por otra parte, se encontró también una diferencia significativa entre las ratas hembra y los machos. El presente estudio permitiría elucidar experimentalmente las acciones que en la vida adulta del individuo ocasionan alteraciones tempranas en los vínculos primarios.

The localization of GluR1 subunits of ionotropic glutamate receptors in the glial cells and inhibitory neurons of cerebellar cortex and their association with the climbing and parallel fibers, and basket cell axons were studied. Samples of P14 and P21 rat cerebellar cortex were exposed to a specific antibody against GluR1 subunit(s) of AMPA receptors and were examined with confocal laser scanning microscopy. GluR1 strong immunoreactivity was confined to Purkinje cell and the molecular layer. Weak GluR1 immunoreactivity was observed surrounding some Golgi cells in the granule cell layer. Intense GluR1 immunoreactivity was localized around Purkinje, basket, and stellate cells. Purkinje cells expressed strong GluR1 immunoreactivity surrounding the cell body, primary dendritic trunk and secondary and tertiary spiny dendritic branches. Marked immunofluorescent staining was also detected in the Bergmann glial fibers at the level of middle and outer third molecular layer. Positive immunofluorescence staining was also observed surrounding basket and stellate cells, and in the capillary wall. These findings suggest the specific localization of GluR1 subunits of AMPA receptors in Bergmann glial cells, inhibitory cerebellar neurons, and the associated excitatory glutamatergic circuits formed by climbing and parallel fibers, and by the inhibitory basket cell axons.

The analysis of pellet contents of Barn Owls from southeastern Oaxaca, Mexico, shows that mammals represent the main prey of this bird. We identified a minimum of 184 individuals from 2 orders, 3 families and 8 species of mammals. The greatest number of prey was from hispid cotton rat (Sigmodon hispidus), which represented 83.69% of the total individuals and 84.68% of the biomass of the sample. From the other 7 species included in the pellets, 3 were very uncommon species: the cozumelan golden bat (Mimon cozumelae), the false vampire bat (Vampyrum spectrum), and the Peter's climbing rat (Tylomys nudicaudus). Bats represented 2.17% of prey number and 0.799% of the total biomass estimated in the sample. Comparisons of these results with the estimated abundances by standard trapping methods show differences. These results corroborate a general pattern of barn owl opportunistic predation over the locally most abundant species and bats as rare prey.

Se analizó el contenido de regurgitaciones de una lechuza de campanario del sureste del estado de Oaxaca México. Se encontró que los mamíferos representan la presa principal de esta ave. Se identificaron restos de 184 individuos pertenecientes a dos órdenes, tres familias y ocho especies. La mayor cantidad de restos correspondieron a la rata de los cañaverales (Sigmodon hispidus), que representó el 83.69% de individuos y 84.68% de la biomasa contenidos en la muestra. De las otras siete especies, tres son raras: los murciélagos Mimon cozumelae y Vampyrum spectrum y la rata arborícola Tylomys nudicaudus. Los murciélagos representaron el 2.17% de las presas y el 0.799% de la biomasa total estimada en la muestra. Los resultados corroboran un patrón general de depredación oportunista sobre las especies localmente más abundantes.

Population dinamics of the big-eared climbing rat (Ototylomys phyllotis) was studied in a subdeciduous tropical rainforest located at Rancho Hobonil, Tzucacab, Yucatan using a mark-recapture technique, from April 1996 to April 1998 during five nights per 24 months. The minimum-number-known-alive technique (MNKA) was used to estimate population size. We captured 123 rats, 52% were females and 48% males. The sex ratio was 1:1 during this study. Density ranged from 10 to 46 ind./ha. And was not significantly correlated with precipitation (p>0.05). Presence of reproductive individuals from both sexes during the majorities of the studied months and the reproductive activity from females suggest a continuous poliestric pattern for this species.

Se estudió la dinámica poblacional de la rata arborícola Ototylomys phyllotis en la selva mediana subcaducifolia del Rancho Hobonil, Tzucacab, Yucatán. Se trabajó de abril de 1996 a abril de 1998, usando el método de captura recaptura y trampeando por cinco noches consecutivas cada mes. La densidad se estimó mediante el método de Número Mínimo de Individuos Vivos (NMIV). Se capturaron un total de 123 individuos, de los cuales el 49% fueron hembras y el 51% machos. La proporción de sexos se mantuvo 1:1. La densidad poblacional fluctuó entre 10 y 46 individuos/ha. No se presentó correlación significativa entre la densidad y la precipitación pluvial anual (p<0.05). Los adultos constituyeron el principal componente de la población. La presencia de reproductores de ambos sexos, así como la actividad reproductiva de las hembras durante la mayoría de los meses de estudio, sugiere que esta especie presenta un patrón reproductivo poliéstrico continuo.