Diacutaneous fibrolysis versus passive stretching after articular immobilization: Muscle recovery and extracellular matrix remodelling

Abstract

Introduction Atrophy and muscle shortening due to articular immobilisation are common problems in musculoskel- etal rehabilitation. Muscle stretching mechanical stimuli might be consid- ered as the golden standard proce- dure to improve muscle flexibility in rehabilitation. Muscle stretching generates mechanotransduction, po- tentiating specific gene expression and promotes sarcomerogenesis and extracellular matrix remodelling on shortened and atrophied muscles. Hypothesis Diacutaneous fibrolysis, like stretch- ing, uses an external force to stress connective and muscle tissues me- chanically to treat muscle short- ening; thus, it is widely used in clinical practice even if there is no evidence to support it. Consider- ing this subject, we have hypoth- esised that diacutaneous fibrolysis can generate mechanotransduction, affecting muscle hypertrophy and extracellular matrix remodelling after immobilisation. Evaluation of hypothesis We have designed a laboratory ex- perimental study with a sample of 50 rats. The sample was randomly di- vided into five groups: Control group (n = 10) with non–immobilised rats; 3–week immobilisation group (n = * Corresponding author Email: wrmartins@me.com 1 Division of Physical Therapy, University of Brasilia, Brasilia, Distrito Federal, Brazil 2 College of Health Sciences, University Center of Brasília, Brasília, Brazil 10); 3–week immobilisation/3–week non–immobilisation group (n = 10); 3–week immobilisation/3–week stretching group (n = 10); and 3– week immobilisation/3–week dia- cutaneous fibrolysis group (n = 10). All rats had their left tibiotarsal joint immobilised in maximum plantar flexion with the orthotics for 3 con- secutive weeks. After the immobilisa- tion period, the intervention groups received their respective interven- tion on their left triceps suralis for 3 weeks. Dependent variables of the study were sarcomere analysis, poly- merase chain reaction, connective tissue density, collagen birefringence and matrix metalloproteinases. Sta- tistical analysis was performed using analysis of variance and Duncan post hoc test was applied for differences between groups. For all calculations, a 5% (p < 0.05) significance level was established. Conclusion If the hypothesis is confirmed, the present study might provide evidence to support the use of this physical therapy resource widely used to treat muscle dysfunctions.