Avaliação de parâmetros histomorfométricos em sóleos de ratos submetidos à remobilização por salto em meio aquático (original) (raw)
Related papers
Revista Brasileira De Medicina Do Esporte, 2013
Introduction: The muscular tissue is able to respond to stimuli such as immobilization that induces hypotrophy, altering muscle performance and it is important to find methods that aim to reverse these deleterious effects in the post-immobilization period. Objective: The aim of this study was to evaluate transverse and longitudinal histomorphometric parameters of the soleus muscle fibers of rats immobilized in shortened position and submitted to remobilization by jumping in water. Methods: 24 rats divided into 3 groups were used: G1 -remobilized freely, G2 -remobilized with jumps daily, and G3 -jumps on alternate days. Immobilization and remobilization occurred in 2 weeks for the right limb. The variables analyzed were: muscle mass, muscle fiber diameter, length and sarcomeres in series estimate along the muscle. Results: There was reduction in muscle mass for both groups. Concerning diameter, there was difference in G1 and G3. No significant differences were observed for muscle length; however, for the sarcomeres in series estimate significant changes were found in all groups. Conclusion: The protocol used presents partial activity against the deleterious effects of immobilization.
Brazilian Journal of Medical and Biological Research, 2008
The objective of the present study was to determine to what extent, if any, swimming training applied before immobilization in a cast interferes with the rehabilitation process in rat muscles. Female Wistar rats, mean weight 260.52 ± 16.26 g, were divided into 4 groups of 6 rats each: control, 6 weeks under baseline conditions; trained, swimming training for 6 weeks; trainedimmobilized, swimming training for 6 weeks and then immobilized for 1 week; trained-immobilized-rehabilitated, swimming training for 6 weeks, immobilized for 1 week and then remobilized with swimming for 2 weeks. The animals were then sacrificed and the soleus and tibialis anterior muscles were dissected, frozen in liquid nitrogen and processed histochemically (H&E and mATPase). Data were analyzed statistically by the mixed effects linear model (P < 0.05). Cytoarchitectural changes such as degenerative characteristics in the immobilized group and regenerative characteristics such as centralized nucleus, fiber size variation and cell fragmentation in the groups submitted to swimming were more significant in the soleus muscle. The diameters of the lesser soleus type 1 and type 2A fibers were significantly reduced in the trained-immobilized group compared to the trained group (P < 0.001). In the tibialis anterior, there was an increase in the number of type 2B fibers and a reduction in type 2A fibers when trained-immobilized rats were compared to trained rats (P < 0.001). In trained-immobilized-rehabilitated rats, there was a reduction in type 2B fibers and an increase in type 2A fibers compared to trained-immobilized rats (P < 0.009). We concluded that swimming training did not minimize the deleterious effects of immobilization on the muscles studied and that remobilization did not favor tissue re-adaptation.
Remobilization in aquatic medium of rat soleus immobilized in lengthening
Journal of Morphological Sciences, 2015
Introduction: The aim of this study was to evaluate histomorphometrically two protocols of aquatic exercise on soleus of rats immobilized in dorsiflexion. Material and Methods: It was used 30 Wistar rats, randomly distributed in five groups: G1 - right hindlimb immobilized in maximum dorsiflexion, for 15 consecutive days, after this the animals were euthanized; G2 - also immobilized in maximum dorsiflexion, for 15 consecutive days, then the animals were freely remobilized; G3 - submitted to remobilization by free swim; G4 - submitted to remobilization with overload of 10% of body weight; G5 - remobilization by jumping in water with overload of 50% of body weight. The immobilization model used was made by plaster cast directly in the lower right limb of each animal. After removing the immobilization, the animals were submitted to remobilization for 10 days according to the group. At the end of the remobilization, the right and left soleus muscles were isolated, cleaned and weighed on...
2011
Background: In rehabilitation, immobilization of skeletal muscles in the elongated position is performed as a countermeasure in order to reverse the effects of severe muscle shortening and postoperative events. The return to normal functional activities is believed to stimulate mechanotransducers capable of reorganizing the normal muscle cytoarchitecture, but few data describing the histopathological changes relating to these procedures are available in the literature. Objectives: To assess and quantify histological abnormalities induced by immobilization of the extensor digitorum longus (EDL) muscle in elongation and to compare them with free movement of the animal after this procedure. Methods: Eighteen female Wistar rats were used, divided into the following groups: Control; Immobilized in plantar flexion (EDL in an elongated position) for 14 days (GI); Immobilized for 14 days and released for 10 days (GIL). EDL fragments were frozen, sectioned and processed through immunohistochemical reactions for collagens I and III and histochemical methods for myofibrillar adenosine triphosphatase using hematoxylin-eosin. Results: GI animals presented slight increases in collagen I and fiber expression in a degenerative/necrotic process, and reductions in the proportion of FT2A fibers and in the diameters of all fiber types, compared with the controls. In GIL, the quantity of collagen I returned to control conditions; the proportion of FT2D decreased; the number of centralized nuclei increased; and the fiber diameter was smaller than in GI. However, FT2B and FT2D expression did not reach the reference values. Conclusions: The data presented show that the recovery of function over a 10-day period was partially efficient with regard to recuperation of the characteristics of the EDL muscle after the period of immobilization. If the data are extrapolated to physiotherapeutic clinical practice, use of procedures directed towards primary dysfunctions of the muscle may favor a morphofunctional response in the segment and its full recovery.
Effect of hind-limb immobilization on contractile and histochemical properties of skeletal muscle
Pfl�gers Archiv European Journal of Physiology, 1973
Both hind limbs of male rats were immobilized in casts. After 4 weeks, serial sections of hind limb muscles were stained for myosin ATPase and NADHdiaphorase. The soleus from immobilized limbs had significantly fewer muscle fibers than the control solcus. Moreover, the soleus from immobilized limbs had a significantly lower percentage and lower number of fibers with low myosin ATPase activity than the so]eus from control rats. Immobilization also resulted in the speed of contraction for the soleus being significantly faster than the soleus from control rats. There were no significant differences in the contractile properties or in the percentages of fibers with low myosin ATPase between rectus femoris muscles from immobilized and control limbs. The deep portion of the rectus femoris from immobilized limbs had a significantly smaller percentage of muscle fibers with high NADHdiaphorase activity than did the rectus femoris from control rats.
Acta Histochemica, 2013
Stretching is frequently used in physiotherapy to minimize or even reverse the alterations that occur after muscle disuse. Alterations that occur after 10 and 21 days of maintained stretch in soleus and plantaris muscles post-disuse were evaluated in the present study in experimental rats. Thirty adult female Wistar rats were divided into seven groups: hindlimb immobilization for 10 days; immobilization and 10 days stretched; immobilized and 21 days stretched; three control groups consisting of animals of different ages and anesthetized group. The right hindlimb was immobilized using a lightweight apparatus composed of two sections: (i) upper part: a small cotton T-shirt and, and (ii) lower part: a steel mesh to fix the ankle in plantar-flexion-shortened position. Fragments of the soleus and plantaris muscle were frozen and processed using histochemical and immunohistochemical methods. Limb immobilization caused important morphological alterations in skeletal muscle including: reduction in the number of type I fibers and an increase in type IIC fibers, reduction in the lesser diameter of type I, IIA and IIAD fibers and in the number of capillaries in soleus muscle. The stretching program applied for 10 days was insufficient to allow recovery from the disuse alterations in both muscles. However, after 21 days there were improved morphological characteristics, size and distribution of the different fibers.
Architectural alterations of rat hind-limb skeletal muscles immobilized at different lengths
Experimental Neurology, 1982
Modifications in architectural profiles of the rat soleus (Sol), medial gastrocnemius (MG), and tibialis anterior (TA) muscles were studied after hind-limb immobilization with an external brace. The muscles were chronically lengthened, shortened, or maintained at approximately resting length (neutral) for 4 weeks, when muscle weight and length, and cross-sectional areas of fibers (F-XSA) and whole muscle were measured. Compared with control muscles, the Sol and MC immobilized in a lengthened position were able to maintain muscle weight better than when immobilized neutrally (approximately 85 versus 55% of control weight) due, in part, to elongation of muscle fibers of the Sol and MG (123 and 111% of control length, respectively). In addition, the F-XSAs of lengthened Sol and MG muscles were 72 and 20% greater, respectively, compared with neutrally fixed muscle fibers. Immobilization in a shortened position resulted in the most extreme muscle atrophy due to significantly shorter fibers (86% of control Sol; 74% of control MG) and reduced F-XSA (42% of control Sol; 42% of control MG). In contrast to the Sol and MG, muscle weight, fiber length, and F-XSA of the TA immobilized with the ankle in extreme plantarflexion were not significantly different from neutrally fixed muscle. That the TA was unaffected in this position is due presumably to a difference in the anatomic attachment of the distal tendon of this muscle, compared with that of the Sol and MC. These results suggest that for muscle affected by immobilization at extreme joint angles, chronic lengthening is a potent stimulus for elongation of muscle fibers and more normally maintained F-XSA. In contrast, the removal of this stimulus leads to extreme muscle atrophy which is manifested by reductions in both muscle fiber length and F-XSA.
Physical Exercise After Immobilization of Skeletal Muscle of Adult and Aged Rats
Revista Brasileira de Medicina do Esporte
Introduction: Immobilization is a treatment technique often used to reduce pain and prevent worsening of the injury. However, it promotes harmful effects on musculoskeletal tissue, resulting in a marked loss of muscle function, which may be aggravated in the elderly. Physical exercise is an important intervention to mitigate these harmful effects. Objective: To analyze possible morphometric changes in the gastrocnemius muscle of rats after immobilization and remobilization with physical exercise. Methods: Fifty-six rats were divided into adult (A) and aged (E) groups and subdivided into adult and aged control (AC and EC), immobilized (AI and EI), free remobilized (AIF and EIF), and remobilized through physical exercise (AIE and EIE). The hind limbs were immobilized with the gastrocnemius muscle in a shortened position for a period of seven days, except for the control group. The exercise protocol consisted of five swimming sessions, once per day (25 minutes/session). The animals wer...
Background: The responses to the use of neuromuscular electrical stimulation (NMES) technique, once or twice a day, are not well described in literature. In this direction, we measured the biomechanical properties and morphological responses of NMES, applied once or twice a day to the gastrocnemius muscle of female rats after cast immobilization in comparison with both sham control and immobilized control groups. Methods: Eighty Female Wistar rats (Body mass±SDg; 210±10g) were divided into five groups: Control (CG); Immobilized (IG); Immobilized then freed (IFG); Immobilized and subjected to NMES once a day (1ESIG) and another twice a day (2ESIG). All groups that suffered cast immobilization were kept in a shortened position for fourteen days, and then NMES was applied once or twice a day for ten consecutive days. The assessments included the mechanical properties of load and elongation at the limit of proportionality, as well as the resilience obtained from the load versus elongation graph. The crosssectional area (CSA), the different fiber type proportions and the perimisial connective area were measured. Results: There was restoration of load at the limit of proportionality (LLP), but not resilience, in the 1ESIG and 2ESIG, as well as restoration of atrophy (CSA) of type I (TIF), type IIad (TIIadF) and type IId (TIIdF) fibers in the 1ESIG, but not in the 2ESIG. An induction of the TIIcF proportions in the 1ESIG and 2ESIG, and a reduction of the TIIad in the 1ESIG were verified. Conclusions: The muscle remobilization intensity can, influence the recovery responses postimmobilization either positively or negatively, for it was observed that NMES once a day can recover most mechanical (except resilience) and structural parameters of gastrocnemius muscle after casting, whereas twice daily, promoted deleterious effects to the much clearer muscles. Moreover, the animals` free movement allowed them to identify their own mobilization limits, which did not cause neither mechanical nor structural overload in the evaluated muscles.