Oral vitamin C attenuates acute ischaemia-reperfusion injury in skeletal muscle

Abstract

I schaemia-reperfusion injury (IRI) is caused byendothelial and subendothelial damage by neutrophil-derived oxidants. Vitamin C is an antioxidant which attenuates endothelial injury after IRI. Our aim was to evaluate the effect of oral vitamin C in the prevention of IRI in skeletal muscle. We used a model of cross-clamping (3 hours) and reperfusion (1 hour) of the cremaster muscle in rats. Muscle function was assessed electrophysiologically by electrical field stimulation. Infiltration by neutrophils was determined by the activity of tissue myeloperoxidase (MPO) and tissue oedema by the wet-to-dry ratio. Neutrophil respiratory burst activity was measured in control animals and groups pretreated with vitamin C.IRI significantly decreased muscle function and increased muscle neutrophil MPO activity and muscle oedema. Pretreatment with vitamin C preserved muscle function and reduced tissue oedema and neutrophil infiltration. Neutrophil respiratory burst activity was reduced in the group treated with vitamin C compared with the control group.We conclude that pretreatment with oral vitamin C protects against acute muscle IRI, possibly by attenuating neutrophil respiratory burst activity.

Pravastatin attenuates tourniquet-induced skeletal muscle ischemia reperfusion injury

“…Advances in molecular biology are increasing our understanding of tourniquet-induced ischemia reperfusion injury at the cellular level, and pharmacological manipulation of the inflammatory cascade may now be possible. Restoration of blood flow to a limb following tourniquet deflation initiates a cascade of cellular and biochemical events that result in muscle edema, necrosis and impaired muscle function (Kearns et al 2001). Although the pathophysiology of ischemia reperfusion injury is not fully understood, an aberrantly activated immune response characterized by neutrophilmediated injury is felt to play a central role in this process.…”

N-acetylcysteine Protects Striated Muscle in a Model of Compartment Syndrome

“…We presumed this would correspond to an improvement in muscle contractile function. From previously published research, the mean contractile force 1 hour after exposure to CS was 47.0 g (SD, 14.45 g) reduced from a peak contractile force of 160.7 g in the control group [27]. We estimated 25% preservation of contractile force would equate to a clinically relevant treatment effect.…”

“…All animals were anesthetized with inhalation of halothane, temperature was maintained using a heating lamp, and rats were monitored using a rectal thermometer. All animals underwent orchidectomy with isolation of the cremaster muscle on its neurovascular pedicle using a previously described technique [27]. The cremaster was introduced into the CS simulation chamber (Fig.…”

Exposure to Direct and Scatter Radiation with Use of Mini-C-Arm Fluoroscopy

“…Because of the low numbers of patients who were known to have been taking supplements before the fracture and the high doses that were used in the study, this source of bias was limited. It is known that vitamin C rapidly reaches a steady state in human plasma at doses of >200 mg per day 5 . With a normal dietary intake of 50 to 60 mg of vitamin C per day added to our trial doses, we did not believe that there was a need to measure plasma levels of vitamin C. Compliance with taking the vitamins as recommended was not confirmed; however, all patients stated that they had consumed all fifty doses.…”

“…Therefore, we performed a dose-response study to replicate and further evaluate our earlier findings. A steady state in human plasma at doses of >200 mg of ascorbic acid (vitamin C) per day has been reported 5 . We performed a multicenter dose-response study of patients with all types of wrist fractures that were treated operatively and nonoperatively; the analysis was performed on the basis of the intention-to-treat principle.…”