Expression of microRNAs miR-126, miR-133b and miR-221 associated with apoptosis in rats submitted to focal cerebral ischemia and physical exercise / Expresión de microRNAs miR-126, miR-133b y miR-221 asociados a apoptosis en ratas sometidas a isquemia cerebral focal y ejercicio físico

SUMMARY: Stroke is one of the main causes of death and disability worldwide. The great impact on the quality of life of the population and on the health system justifies that we seek relevant alternatives to reduce the incidence and improve the treatment and recovery of patients affected by this disease. Physical exercise appears as an important tool in this scenario, being already pointed out as a possible therapeutic approach for the prevention of non-contagious chronic diseases. In this context, biomarkers such as miRNAs that respond to physical exercise and are directly related to several epigenetic mechanisms appear. Therefore, explaining the molecular mechanisms involved during physical exercise will lead to a better understanding of each stimulus and the dose to be used to better respond to each situation, thus being a promising approach for the evolution of prescription and control of training and processes recovery from various diseases, including stroke. Forty-eight Wistar rats were used, divided into four experimental groups: control group, ischemia group, physical exercise group and exercise + ischemia group. Real-time PCR methodology was used to analyze the expression of miRNAs: miR-126, miR-133b and miR-221. In our study we observed a significant difference in the expression of miR- 221 between the control group and the others groups. However, microRNAs: miR-126 and miR-133b do not show significant differences in expression between groups.

El ictus es una de las principales causas de muerte y discapacidad en todo el mundo. El gran impacto en la calidad de vida de la población y en el sistema de salud justifica buscar alternativas pertinentes para reducir la incidencia y mejorar el tratamiento y recuperación de los pacientes afectados por esta enfermedad. El ejercicio físico aparece como una herramienta importante en este escenario, siendo ya señalado como un posible abordaje terapéutico para la prevención de enfermedades crónicas no contagiosas. En este contexto, aparecen biomarcadores como los miRNAs que responden al ejercicio físico y están directamente relacionados con varios mecanismos epigenéticos. Por lo tanto, explicar los mecanismos moleculares involucrados durante el ejercicio físico conducirá a una mejor comprensión de cada estímulo y la dosis a utilizar para responder mejor a cada situación, siendo así un enfoque prometedor para la evolución de la prescripción, el control del entrenamiento y los procesos de recuperación de diversas enfermedades, incluido el accidente cerebrovascular. Se utilizaron cuarenta y ocho ratas Wistar, divididas en cuatro grupos experimentales: grupo control, grupo isquemia, grupo ejercicio físico y grupo ejercicio + isquemia. Se utilizó la metodología de PCR en tiempo real para analizar la expresión de miRNAs: miR-126, miR-133b y miR-221. En nuestro estudio observamos una diferencia significativa en la expresión de miR-221 entre el grupo control y los demás grupos. Sin embargo, los microARN: miR-126 y miR-133b no mostraron diferencias significativas en la expresión entre grupos.

Morphology and morphometry of the vagus nerve in male and female spontaneously hypertensive rats.

The vagus nerve is an important component of the efferent arm of the baroreflex. Blood pressure levels as well as baroreflex control of circulation are significantly different in male and female spontaneously hypertensive rats (SHR). We proposed to investigate the morphometric differences between genders using the vagus nerve of SHR. Adult animals (20 weeks old) were anesthetized and had their arterial pressure (AP) and heart rate (HR) recorded by a computerized system. The rats were then systemically perfused with a fixative solution and had their cervical vagi nerves prepared for light microscopy. Proximal and distal segments of the left and right vagi nerves were evaluated for morphometric parameters including fascicle area and diameter, myelinated fiber number, density, area and diameter. Comparisons were made between sides and segments on the same gender as well as between genders. Differences were considered significant when p<0.05. Male SHR had significantly higher AP and HR. Morphometric data showed no differences between the same levels of both sides and between segments on the same side for male and female rats. In addition, no significant morphometric differences were observed when genders were compared. This is the first description of vagus nerve morphometry in SHR indicating that gender differences in AP and HR cannot be attributed to dissimilarities in vagal innervation of the heart. These data provide a morphological basis for further studies involving functional investigations of the efferent arm of the baroreflex in hypertension.