Ana Elisa Toscano

Sertraline delays the somatic growth and reflex ontogeny in neonate rats

This study investigated the somatic maturation and ontogeny of reflexes in neonate rats treated with sertraline (Sert) during the suckling period. The animals were divided into four groups; three that received daily doses of Sert (5, 10 or 15 mg/kg s.c.; groups Sert5, Sert10, and Sert15, respectively), and a fourth group that received distilled water (Dw) (1 ml/kg/b.w.). Growth indicators (body weight, axis of the head and tail length) were measured daily, from the 1st to the 21st postnatal day. The reflexes (righting, free-fall righting, negative geotaxis, cliff avoidance, auditory startle response, vibrissa placing and palm grasp) and physical-feature maturation (ear unfolding, auditory conduit opening, irruption of the lower incisors and eye opening) were recorded each day of the animals life. All groups were compared to the Dw group. The body weight gain was reduced in all the Sert groups. Moreover, a delay in the growth of the body length was observed in all the Sert groups. Higher Sert doses reduced the speed of growth in the tail length. The medio-lateral head axis reduced in Sert15 and Sert5 doses. Otherwise, Sert10 had a temporary acceleration in this growth, but the growth of the anteroposterior head axis had a delay in all the Sert groups. The highest doses induced a delay in physical-feature maturation. The palm grasp reflex (disappearance) was retarded in Sert10; cliff avoidance advanced in Sert10; negative-geotaxis and free-fall righting retarded in Sert15. The findings suggest that altered serotonergic system activity induced by sertraline early in life could play a role in the retardation of the somatic growth ontogeny as well as a delay in the maturation of some reflexes.

Passive stiffness of rat skeletal muscle undernourished during fetal development

OBJECTIVES: The aim of the study was to investigate the effect of fetal undernutrition on the passive mechanical properties of skeletal muscle of weaned and young adult rats. INTRODUCTION: A poor nutrition supply during fetal development affects physiological functions of the fetus. From a mechanical point of view, skeletal muscle can be also characterized by its resistance to passive stretch. METHODS: Male Wistar rats were divided into two groups according to their mothers diet during pregnancy: a control group (mothers fed a 17% protein diet) and an isocaloric low‐protein group (mothers fed a 7.8% protein diet). At birth, all mothers received a standardized meal ad libitum. At the age of 25 and 90 days, the soleus muscle and extensor digitorum longus (EDL) muscles were removed in order to test the passive mechanical properties. A first mechanical test consisted of an incremental stepwise extension test using fast velocity stretching (500 mm/s) enabling us to measure, for each extension stepwise, the dynamic stress (σd) and the steady stress (σs). A second test consisted of a slow velocity stretch in order to calculate normalized stiffness and tangent modulus from the stress–strain relationship. RESULTS: The results for the mechanical properties showed an important increase in passive stiffness in both the soleus and EDL muscles in weaned rat. In contrast, no modification was observed in young adult rats. CONCLUSIONS: The increase in passive stiffness in skeletal muscle of weaned rat submitted to intrauterine undernutrition it is most likely due to changes in muscle passive stiffness.

Do malnutrition and fluoxetine neonatal treatment program alterations in heart morphology

Growth and development events are observed in all organisms and can be modified by exogenous factors such as nutritional changes. Drastic morphological and functional alterations may occur during a vulnerable stage of development. The aim of this study was to investigate if malnutrition and/or fluoxetine neonatal treatment program alterations in heart morphology during the postnatal period. The sample consisted of 48 albino Wistar male rats. The rats were divided into two groups: nourished and malnourished. Pharmacologic manipulation was performed during the suckling period. The animals of each group were divided into two subgroups: saline-nourished and saline-malnourished, treated with sodium chloride solution, and fluoxetine-nourished and fluoxetine-malnourished, treated with fluoxetine. Half of the individuals in each subgroup were weighed and sacrificed on day 30 and the other half on day 71. Myocardial perfusion was performed and the heart subsequently weighed. The ventricles were cross-sectioned into two parts, which were fixed, dehydrated and sectioned. There were differences in body weight, heart weight, cross-sectional area and perimeter of the heart and in the cross-sectional area and perimeter of the cardiac cells among the groups at the different ages. Malnutrition appears to program alterations in heart morphology. However, malnourished animals that had undergone drug treatment did not exhibit the same changes.

Differential developmental programming by early protein restriction of rat skeletal muscle according to its fibre-type composition

Differences in fibre‐type composition of skeletal muscle have been associated with obesity and insulin resistance. As a poor nutrient environment early in life is a predisposing factor for the development of obesity and related metabolic diseases at adulthood, this study aimed at determining the long‐term consequences of maternal undernutrition on the structural and metabolic properties of two skeletal muscles characterized by their different fibre‐type composition and metabolic properties.

Automatic system for analysis of locomotor activity in rodents—A reproducibility study

Automatic analysis of locomotion in studies of behavior and development is of great importance because it eliminates the subjective influence of evaluators on the study. This study aimed to develop and test the reproducibility of a system for automated analysis of locomotor activity in rats. For this study, 15 male Wistar were evaluated at P8, P14, P17, P21, P30 and P60. A monitoring system was developed that consisted of an open field of 1m in diameter with a black surface, an infrared digital camera and a video capture card. The animals were filmed for 2 min as they moved freely in the field. The images were sent to a computer connected to the camera. Afterwards, the videos were analyzed using software developed using MATLAB® (mathematical software). The software was able to recognize the pixels constituting the image and extract the following parameters: distance traveled, average speed, average potency, time immobile, number of stops, time spent in different areas of the field and time immobile/number of stops. All data were exported for further analysis. The system was able to effectively extract the desired parameters. Thus, it was possible to observe developmental changes in the patterns of movement of the animals. We also discuss similarities and differences between this system and previously described systems.

MORPHOMETRIC STUDY OF MENISC OF THE KNEE JOINT

Investigamos los aspectos morfometricos de los meniscos de la articulacion de la rodilla tales como: grosor de la circunferencia externa y el ancho de los meniscos, relacion area del menisco/area del platillo de la tibia y la distancia entre los cuernos posterior y anterior de cada menisco. Fueron analizados 44 meniscos de 22 rodillas de cadaveres humanos, adultos, de sexo masculino. Las variables morfometricas ancho y grosor fueron evaluadas en tres puntos distintos: tercio anterior, tercio medio y tercio posterior, y sus valores comparados entre los compartimientos medial y lateral. En el menisco medial no hubo diferencia significativa, en lo que se refiere al grosor, entre los tercios anterior, medio y posterior, mientras que en el menisco lateral, el tercio medio se mostro como sitio de mayor grosor. En cuanto al ancho, se observo que el tercio posterior del menisco medial fue estadisticamente el sitio mas ancho del menisco, mientras que en el menisco lateral no hubo ninguna diferencia significativa entre los tres puntos analizados. La relacion area del menisco/area del platillo de la tibia y la distancia entre los cuernos anterior y posterior fueron mayores en el compartimiento medial. Los resultados morfometricos de los meniscos demostraron relacion con los datos clinicos. El menisco medial se mostro mas ancho y ocupando una area de cobertura del platillo de la tibia mas grande, lo que justifica la mayor incidencia de lesiones que afectan ese menisco. De la misma manera, los valores de medicion en su tercio medio, confirman la mayor frecuencia de rupturas en esa region

Neonatal low-protein diet reduces the masticatory efficiency in rats

Little is known about the effects of undernutrition on the specific muscles and neuronal circuits involved in mastication. The aim of this study was to document the effects of neonatal low-protein diet on masticatory efficiency. Newborn rats whose mothers were fed 17% (nourished (N), n 60) or 8% (undernourished (U), n 56) protein were compared. Their weight was monitored and their masticatory jaw movements were video-recorded. Whole-cell patch-clamp recordings were performed in brainstem slice preparations to investigate the intrinsic membrane properties and N-methyl-d-aspartate-induced bursting characteristics of the rhythmogenic neurons (N, n 43; U, n 39) within the trigeminal main sensory nucleus (NVsnpr). Morphometric analysis (N, n 4; U, n 5) were conducted on masseteric muscles serial cross-sections. Our results showed that undernourished animals had lower numbers of masticatory sequences (P=0·049) and cycles (P=0·045) and slower chewing frequencies (P=0·004) (N, n 32; U, n 28). Undernutrition reduced body weight but had little effect on many basic NVsnpr neuronal electrophysiological parameters. It did, however, affect sag potentials (P<0·001) and rebound firing (P=0·005) that influence firing pattern. Undernutrition delayed the appearance of bursting and reduced the propensity to burst (P=0·002), as well as the bursting frequency (P=0·032). Undernourished animals showed increased and reduced proportions of fibre type IIA (P<0·0001) and IIB (P<0·0001), respectively. In addition, their fibre areas (IIA, P<0·001; IIB, P<0·001) and perimeters (IIA, P<0·001; IIB, P<0·001) were smaller. The changes observed at the behavioural, neuronal and muscular levels suggest that undernutrition reduces chewing efficiency by slowing, weakening and delaying maturation of the masticatory muscles and the associated neuronal circuitry.

Effects of maternal low-protein diet on parameters of locomotor activity in a rat model of cerebral palsy.

Children with cerebral palsy have feeding difficulties that can contribute to undernutrition. The aim of this study was to investigate the effect of early undernutrition on locomotor activity and the expression of the myofibrillar protein MuRF‐1 in an experimental model of cerebral palsy (CP). In order to achieve this aim, pregnant rats were divided into two groups according to the diet provided: Normal Protein (NP, n = 9) and Low Protein (LP, n = 12) groups. After birth, the pups were divided into four groups: Normal Protein Sham (NPS, n = 16), Normal Protein Cerebral Palsy (NPCP, n = 21), Low Protein Sham (LPS, n = 20) and Low Protein Cerebral Palsy (LPCP, n = 18) groups. The experimental cerebral palsy protocol consisted of two episodes of anoxia at birth and during the first days of life. Each day, nitrogen flow was used (9l/min during 12 min). After nitrogen exposure, sensorimotor restriction was performed 16 h per day, from the 2nd to the 28th postnatal day (PND). Locomotor activity was evaluated at 8th, 14th, 17th, 21th and 28th PND. At PND 29, soleus muscles were collected to analyse myofibrillar protein MuRF‐1. Our results show that CP animals decreased body weight (p < 0.001), which were associated with alterations of various parameters of locomotor activity (p < 0.05), compared to their control. Undernourished animals also showed a decrease (p < 0.05) in body weight and locomotor activity parameters. Moreover, CP decreased MuRF‐1 levels in nourished rats (p = 0.015) but not in undernourished rats. In summary, perinatal undernutrition exacerbated the negative effects of cerebral palsy on locomotor activity and muscle atrophy, but it appears not be mediated by changes in MuRF‐1 levels.

THE ARTICULAR MUSCLE OF THE KNEE: MORPHOLOGY AND DISPOSITION

Con el objetivo de investigar los aspectos morfologicos y las relaciones del musculo articular de la rodilla, asi como la disposicion de las fibras musculares a nivel del femur, ademas de comparar la masa muscular del referido musculo con el resto de la masa muscular del miembro inferior, fueron analizados 15 miembros inferiores de cadaveres humanos adultos, de ambos sexos, fijados en formol y seccionados transversalmente, a nivel del tercio medio del muslo y tercio proximal de la pierna. El musculo articular de la rodilla estaba presente en todo el material analizado y en el 93,3% de los casos tenia su punto de origen en la parte anterior distal del femur. Entre las piezas analizadas, un 40% mostro una masa muscular bastante reducida y en forma trapezoidal. Ese musculo presento en la insercion una distancia promedio de 3,07 cm arriba del borde superior de la troclea, variando los haces musculares entre 2 y 7. Estos, en su mayoria, presentaron una direccion vertical. El musculo mostro una disposicion anterior en el tercio distal del femur. Nuestro resultado sugiere que el tamano y las relaciones del musculo articular de la rodilla con la bolsa sinovial suprapatelar, pueden estar directamente relacionados con el resto de masa muscular del miembro inferior. Por tal motivo, cuando se trabaja para aumentar el tono muscular del musculo recto femoral, se esta provocando, de manera indirecta, la hipertrofia del musculo articular de la rodilla y potenciando su desempeno en la cavidad articular

Resistance Training Alters the Proportion of Skeletal Muscle Fibers but Not Brain Neurotrophic Factors in Young Adult Rats.

Abstract Antonio-Santos, J, Ferreira, DJS, Gomes Costa, GL, Matos, RJB, Toscano, AE, Manhães-de-Castro, R, and Leandro, CG. Resistance training alters the proportion of skeletal muscle fibers but not brain neurotrophic factors in young adult rats. J Strength Cond Res 30(12): 3531–3538, 2016—Resistance training (RT) is related to improved muscular strength and power output. Different programs of RT for rats have been developed, but peripheral and central response has not been evaluated directly in the same animal. To test the hypothesis that RT induces central and peripheral adaptations, this study evaluated the effects of a RT on the performance of a weekly maximum overload test, fiber-type typology, and brain neurotrophic factors in young adult rats. Thirty-one male Wistar rats (65 ± 5 days) were divided in 2 groups: nontrained (NT, n = 13) and trained (T, n = 18). Trained group was submitted to a program of RT ladder climbing, gradually added mass, 5 days per week during 8 weeks at 80% of individual maximum overload. This test was weekly performed to adjust the individual load throughout the weeks for both groups. After 48 hours from the last session of exercise, soleus and extensor digital longus (EDL) muscles were removed for myofibrillar ATPase staining analysis. Spinal cord, motor cortex, and cerebellum were removed for RT-PCR analysis of BDNF and insulin-like growth factor-1 (IGF-1) gene expression. In EDL muscle, T animals showed an increase in the proportion of type IIb fibers and a reduction of type IIa fibers. Insulin-like growth factor-1 gene expression was reduced in the cerebellum of T animals (NT: 1.025 ± 0.12; T: 0.57 ± 0.11). Our data showed that 8 weeks of RT were enough to increase maximum overload capacity and the proportion of glycolytic muscle fibers, but there were no associations with the expression of growth neurotrophic factors.