COMPARISON OF THE EFFICACY OF LOSARTAN, HYDROCORTISONE AND ACETYLSALICYLIC ACID (ASA) IN PREVENTING THE DEVELOPMENT OF FIBROUS SCAR TISSUE IN SKELETAL MUSCLE

Otavio Melo-Silva Junior,Luiz Ronaldo Alberti,Cristiana Buzelin Nunes,Laurice B Freitas,Tchalton Amador Corrêa,Marilia F Silva

doi:10.1590/1517-869220182406149841

Abstract

ABSTRACT Objective: To analyze fibrous scar tissue inhibition capacity with the use of losartan, hydrocortisone and acetylsalicylic acid. Method: The sample consisted of 120 male heterogeneic Wistar rats with a muscle laceration model. The rats were divided into four groups of 30 animals each: control group, losartan group, ASA group and hydrocortisone group. The animals were anesthetized and a 2.5 cm longitudinal incision was made in the left thoracolumbar paravertebral region. The muscles were subjected to a Grade III lesion caused by applying Kelly hemostatic forceps for 60 seconds, followed by sectioning with scissors. The skin was sutured with 3-0 nylon monofilament thread. The animals were placed in individual cages with plenty of food and water. The losartan group received losartan diluted in water at a dose of 0.1 mg/mL (10 mg/kg/day), the ASA Group received a 3 mg/mL ASA solution (300 mg/kg/day), and the hydrocortisone group received a 0.2 mg/mL hydrocortisone solution (20 mg/kg/day). Results: The control, losartan, hydrocortisone and aspirin groups had a fibrotic area of 0.95 ± 0.35 mm, 0.55 ± 0.34 mm, 0.93 ± 0.33 mm, and 0.66 ± 0.36 mm, respectively. We observed a significantly smaller fibrotic area in the losartan group compared to the control (p=0.01) and hydrocortisone (p=0.01) groups. There were no significant differences among the other groups. Conclusion: The healing of striated skeletal muscle produced less fibrous scar tissue when exposed to losartan in comparison to the control group or the hydrocortisone group. Level of Evidence I; Randomized double-blind placebo-controlled study.

Highlights

Skeletal muscle lesions are responsible for a large number of complaints in orthopedic patients; for example, those with pain after intensive efforts and sports practices, and in victims of low- and high-energy impact accidents
The rats were divided into four groups of 30 animals each: control group, losartan group, acetylsalicylic acid (ASA) group and hydrocortisone group
The healing of striated skeletal muscle produced less fibrous scar tissue when exposed to losartan in comparison to the control group or the hydrocortisone group

Summary

Introduction

Skeletal muscle lesions are responsible for a large number of complaints in orthopedic patients; for example, those with pain after intensive efforts and sports practices, and in victims of low- and high-energy impact accidents. The development of fibrosis within tissue leads to a loss of strength and muscular endurance; when an individual is subsequently exposed to new muscle stretching or trauma, new lesions may occur more readily, reinitiating the healing process, and perpetuating the presence of the lesion.[1]. The formation of fibrous tissue is the end result of any healing process, and predisposes skeletal muscle to recurrent lesions, limiting functional recovery. Inflammation and collagen synthesis by fibroblasts are important events in the healing process. This process is crucial for tissue repair, since collagen is the main component of the extracellular matrix. Reduced production of scar tissue (fibrosis) and stimulation of muscle fiber regeneration after an injury can lead to maintained contractility after injury, preventing functional loss and accelerating rehabilitation[2]

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