Histomorphometric alterations of muscle soleus provoked by drawn out immobilization: experimental study with wistar lineage rats

Priscila Daniele De Oliveira,Célia Regina De Godoy Gomes,Deise A De Almeida Pires-Oliveira,Rodrigo Franco De Oliveira,Sonia Maria Marques Gomes Bertolini

doi:10.1590/0103-5150.028.002.ao09

Abstract

Objective This study has as objective to analyze the effect of joint immobilization of the soleus muscle of posterior members of rats on morphometric profile view, at periods of 21 and 45 days. Materials and methods Ten male Rattus novergicus albinus, Wistar variety, were used, separated into two groups (group I and II), of 5 animals each, with the first group submitted to immobilization for 21 days and the second for 45 days. The experiment control was acquired from the right contralateral member of each animal. The immobilization of the left posterior member was done by adapted orthesis. The morphometric analysis of soleus was by non-serial cross sections, 8μm thick. Results From the obtained images, the muscle fibers areas were analyzed, including the form of the fibers, comparing with the control group. In both the periods of immobilization cross sections of staple fibres had reduction of the section area, front to the comparison to its respective member has controlled, with significant important (p < 0.0001), especially it enters the experimental groups of 21 and 45 days. Conclusion It can be concluded that immobilization to articulate of rats per 21 and 45 days modifies the section area more transversa of staple fibres of the sóleo muscle and deleterious effect of more significant the cellular components for drawn out periods.

Highlights

Gomes et al [17] add that the muscle disuse promotes the decrease in the density of capillaries and the spreading of the intramuscular connective tissue both in the perimysium and in the endomysium, besides promoting an increasing of collagen fibers of the tissue [18], reduction of glycogen reserves, increase in fatigability [19], decrease in Histomorphometric alterations of muscle soleus provoked by drawn out immobilization 291 size and number of mitochondria, increase in lactate concentration with the work [20] and lastly, skeletal muscle hypertrophy [19, 21]
It is important to emphasize the observation (p < 0.0001) of significant importance among the experimental groups of 21 and 45 days, suggesting the progressive exacerbation of hypertrophic degree when related to the immobilization time (Table 1). It was observed in the controlled group the presence of muscle fibers with polygon outlines and regular fascicular pattern (Figures 1A and 1C). It was observed in the experimental group the presence of distinct outlines of muscle fibers from soleus muscle
It was verified in this group the rounding and diameter decrease of muscle fibers, as well as the increase of the space occupied by endomysium and perymisium demonstrating a clear increase in the occupied area by the connective tissue (Figures 1B and 1D)

Summary

Introduction

In the clinical practice it is observed a tendency to precocious immobilization of a body segment [1, 2] due to orthopedic or neurological affections, such as ligament ruptures, fractures and muscle lesions [3, 4].The immobilization of a body segment comprehends local rest, continuous and rigid [5] with morphological, physiological and biochemical manifestations in the skeletal musculature [6, 7, 8, 9, 10] observed in animals [11] as well in human beings [12].The restriction to movement by immobilization, because of its non-contribution to homeostatic maintenance in anabolic and catabolic reactions, converges to alterations of trophic character [4], and, yet can be distinguished by the strength decreasing, by the muscle size, the fiber area [13], the extensibility [14], the resistance of ligaments and tendons, contracture formation, electrical activity alteration [15] and reduction of the number of sarcomeres in series resulting in muscle rigidity during the first week of immobilization [16].In this sense, Gomes et al [17] add that the muscle disuse promotes the decrease in the density of capillaries and the spreading of the intramuscular connective tissue both in the perimysium and in the endomysium, besides promoting an increasing of collagen fibers of the tissue [18], reduction of glycogen reserves, increase in fatigability [19], decrease in Histomorphometric alterations of muscle soleus provoked by drawn out immobilization 291 size and number of mitochondria, increase in lactate concentration with the work [20] and lastly, skeletal muscle hypertrophy [19, 21].According to Appel [22] and Glass [23], hypertrophy may be defined as a consequence of the subtraction in the muscle protein synthesis and/or development of it, and the decrease of availability of energetic substrates. The restriction to movement by immobilization, because of its non-contribution to homeostatic maintenance in anabolic and catabolic reactions, converges to alterations of trophic character [4], and, yet can be distinguished by the strength decreasing, by the muscle size, the fiber area [13], the extensibility [14], the resistance of ligaments and tendons, contracture formation, electrical activity alteration [15] and reduction of the number of sarcomeres in series resulting in muscle rigidity during the first week of immobilization [16]. Taking into account that the causes are distinguished among age, gender, muscle group (extensor/flexor), fiber type, length, immobilization time and position in which the muscle is immobilized [22]

Methods

Results

Discussion

Conclusion