Morphologic evaluation and comparison between types of muscle fibers of the lateral and medial gastrocnemius and flexor halucis longus after painful stimulation in the neonatal period

Abstract

This study aims to evaluate and compare the muscle fibers of the lateral gastrocnemius muscle, medial gastrocnemius (bilateral) in rats, males and females exposed to painful stimuli after birth, at different stages of development. For the study, will be used a control group of 48 animals (6 females and 6 males with 15 days old, 6 females and 6 males with 30 days old, 6 females and 6 males at 90 days old, 6 females 6 males with 180 days of life) and a group of 48 animals to be subjected to painful procedures in the neonatal period (6 females and 6 males with 15 days old, 6 females and 6 males with 30 days old, 6 females and 6 males with 90 days old, 6 females and 6 males with 180 days of life). Pain assessment is performed using the paw pressure and tactile stimulation, assessment of motor function will be carried out using the Functional Assessment of Tibial Nerve. This evaluation will take place every 15 days, during all experimental. After the last functional test, the animals are weighed, anesthetized and perfused with a solution of buffered saline solution followed by Karnowisky. Lateral gastrocnemius muscles and bilateral medial be dissected, prepared with histological techniques for immunostaining of muscle fiber types and cross-sectioned for analysis at the level of light microscopy. The statistical analysis will be performed by specific statistical tests. Considered to be significant differences when p <0.05. (AU)