Free radical activity, antioxidant enzyme, and glutathione changes with muscle stretch injury in rabbits

Abstract

The present study investigated changes in rate of free radical production, antioxidant enzyme activity, and glutathione status immediately after and 24 h after acute muscle stretch injury in 18 male New Zealand White rabbits. There was no change in free radical production in injured muscles, compared with noninjured controls, immediately after injury (time 0; P = 0.782). However, at 24 h postinjury, there was a 25% increase in free radical production in the injured muscles. Overall, there was an interaction (time and treatment) effect (P = 0.005) for free radical production. Antioxidant enzyme activity demonstrated a treatment (injured vs. control) and interaction effect for both glutathione peroxidase (P = 0.015) and glutathione reductase (P = 0.041). There was no evidence of lipid peroxidation damage, as measured by muscle malondialdehyde content. An interaction effect occurred for both reduced glutathione (P = 0.008) and total glutathione (P = 0.015). Morphological analysis (hematoxylin and eosin staining) showed significant polymorphonuclear cell infiltration of the damaged region at 24 h postinjury. We conclude that acute mechanical muscle stretch injury results in increased free radical production within 24 h after injury. Antioxidant enzyme and glutathione systems also appear to be affected during this early postinjury period.

Changes in Nitric Oxide and Inducible Nitric Oxide Synthase Following Stretch-Induced Injury to the Tibialis Anterior Muscle of Rabbit

“…Our model of a single stretch-induced injury to skeletal muscle has been described [18]. Briefly, all animals were anesthetized with an intramuscular preparation of ketamine (100 mg/kg), xylazine (2.5 mg/kg), and acepromazine (3 mg/kg).…”

“…We employed an isokinetic injury apparatus that quantifies tibialis anterior (TA) muscle-tendon shortening according to the method previously reported [18][19][20]. This in vivo model of acute mechanical muscle stretch injury would be different from the injury observed with exhaustive exercise and reported eccentric muscle contractions.…”

“…This in vivo model of acute mechanical muscle stretch injury would be different from the injury observed with exhaustive exercise and reported eccentric muscle contractions. Because injury was created by using a single stretch and stimulation of the muscle-tendon unit rather than repeated eccentric muscle contractions, this model can mimic the clinical injury pattern that occurs with a single stretch of the muscle-tendon unit, for example, the so-called "hamstring strain" [18]. However, we confirmed that this in vivo model of stretch injury showed a visible hematoma at the muscle-tendon junction, and that histological evaluation 48 h after injury revealed fiber tearing and inflammation at this junction [19].…”

ROS Scavenging Activity and Muscle Damage Prevention in Eccentric Exercise in Rats

“…The involvement of reactive oxygen species (ROS) in exercise-induced injury is increasingly apparent [13,14]. Aerobic metabolism during exercise and the inflammatory processes in damaged muscle can both produce ROS [14].…”

“…Aerobic metabolism during exercise and the inflammatory processes in damaged muscle can both produce ROS [14]. Other reports indicate that antioxidant enzyme systems undergo adaptive modulation in response to shortand long-term exercise [15], and that training can strengthen defenses against ROS in muscle [16].…”