A New Surgical Model of Skeletal Muscle Injuries in Rats Reproduces Human Sports Lesions

Abstract

Skeletal muscle injuries are the most common sports-related injuries in sports medicine. In this work, we have generated a new surgically-induced skeletal muscle injury in rats, by using a biopsy needle, which could be easily reproduced and highly mimics skeletal muscle lesions detected in human athletes. By means of histology, immunofluorescence and MRI imaging, we corroborated that our model reproduced the necrosis, inflammation and regeneration processes observed in dystrophic mdx-mice, a model of spontaneous muscle injury, and realistically mimicked the muscle lesions observed in professional athletes. Surgically-injured rat skeletal muscles demonstrated the longitudinal process of muscle regeneration and fibrogenesis as stated by Myosin Heavy Chain developmental (MHCd) and collagen-I protein expression. MRI imaging analysis demonstrated that our muscle injury model reproduces the grade I-II type lesions detected in professional soccer players, including edema around the central tendon and the typically high signal feather shape along muscle fibers. A significant reduction of 30% in maximum tetanus force was also registered after 2 weeks of muscle injury. This new model represents an excellent approach to the study of the mechanisms of muscle injury and repair, and could open new avenues for developing innovative therapeutic approaches to skeletal muscle regeneration in sports medicine.

Postinjury Exercise and Platelet-Rich Plasma Therapies Improve Skeletal Muscle Healing in Rats But Are Not Synergistic When Combined

“…11 After muscle injury, dMHC expression is commonly detected at days 2 to 3 after injury and progressively increases up to day 14 when its expression gradually declines due to the successive replacement by adult muscle myosin isoforms. 11,12,36,37…”

“…After 2 weeks of preinjury training, skeletal muscle injury was induced surgically just proximal to the myotendinous junction of the medial gastrocnemius muscle in all rats, as previously described. 12 Rats were anaesthetized with a mixture of ketamine (75 mg/kg, intraperitoneally [ip]) and xylazine (10 mg/kg, ip) before the surgical procedure. The muscle injury was generated by using an yy 18-gauge biopsy needle (Bard Monopty Disposable Core Biopsy Instrument, Bard Biopsy Systems).…”

“…11 After muscle injury, dMHC expression is commonly detected at days 2 to 3 after injury and progressively increases up to day 14 when its expression gradually declines due to the successive replacement by adult muscle myosin isoforms. 11,12,36,37 The cross-sectional area (CSA) of newly formed muscle fibers was measured in collagen I immunofluorescence microphotographs. Three images were randomly selected within the injured area of gastrocnemius muscle cross sections by use of a BX-61 microscope (Olympus) equipped with a DP72 camera (Olympus) and CellSens Digital Imaging software (version 1.9).…”

“…The aim of our study was to evaluate the beneficial effects of an early, active rehabilitation protocol or PRP administration after muscle injury and to determine the potential synergistic effect of both treatments when combined, by using a well-characterized experimental skeletal muscle injury model in rats that reproduces the injuries seen in human athletes. 12 To do this, we wanted to simulate the study protocols of the recently published RCTs on PRP therapy in the treatment of injured skeletal muscle 18,45 by addressing the respective individual effects of PRP and early active rehabilitation as well as their potential interaction on the experimental skeletal muscle injury model using a classic 2 × 2 study design.…”

Intramuscular Injection of Combined Calf Blood Compound (CFC) and Homeopathic Drug Tr14 Accelerates Muscle Regeneration In Vivo

“…To evaluate the healing process in structural skeletal muscle injury, we sought to use a mechanical injury model with laceration of the quadriceps femoris muscle in rats, with modification to reflect the protocol of Nakaska et al [53]. Surgical lesion models have been described to best represent injuries arising during the performance of sporting activities [54,55].…”