Effects of Trans-Cinnamaldehyde on Reperfused Ischemic Skeletal Muscle and the Relationship to Laminin.

PURPOSE: Ischemia-reperfusion (I-R) injury is a serious problem caused by vascular trauma, tourniquet use and/or compartment syndrome. Studies have reported that skeletal muscle function is impaired due to the lower extremity I-R injury. There are insufficient studies on the treatment methods used for the recovery of dysfunction. This study is designed to investigate the effects of trans-cinnamaldehyde (TCA), a volatile oil of cinnamon structure, on the contractile dysfunction due to I-R injury of rat extensor-digitorum-longus (EDL) muscle. MATERIALS AND METHODS: Sprague-Dawley rats were randomly divided into three groups. Except for the animals in the control group, all animals received saline (3-ml/kg) or TCA solution (30-mg/kg) which was administered orally three times with an 8-h interval before ischemia. After 24-hours, experimental groups were subjected to 3-h of lower extremity ischemia followed by 5-h reperfusion period. Then, the compound muscle action potential (CMAP) and mechanical activity of muscle were recorded using the standard electro-biophysical techniques. RESULTS: There was a decrease in the maximum contractile force in I-R group compared to the control group (p < 0.05). Oxidative damage indicator (MDA) and antioxidant indicator (CAT) increased in the EDL muscle and serum samples in the I-R group (p < 0.05). Laminin expression showed a reduction in the I-R group (p < 0.05). It was seen that TCA achieve again the maximum contraction force in the EDL muscle (p < 0.05) and maintain the expression of laminin (p > 0.05). CONCLUSION: We concluded that TCA has a potential protective effect with antioxidant effects against I-R injury and may maintain laminin levels.

Alpha 7 integrin preserves the function of the extensor digitorum longus muscle in dystrophin-null mice.

The dystrophin-associated glycoprotein complex (DGC) and the α7ß1-integrin complex are two independent protein complexes that link the extracellular matrix with the cytoskeleton in muscle cells. These associations stabilize the sarcolemma during force transmission. Loss of either one of these complexes leads to muscular dystrophy. Dystrophin is a major component of the DGC. Its absence results in Duchenne muscular dystrophy (DMD). Because α7-integrin overexpression has been shown to ameliorate muscle histopathology in mouse models of DMD, we hypothesize that the α7ß1-integrin complex can help preserve muscle function. To test this hypothesis, we evaluated muscle force, elasticity, and the viscous property of the extensor digitorum longus muscle in 19-day-old normal BL6, dystrophin-null mdx4cv, α7-integrin-null, and dystrophin/α7-integrin double knockout mice. While nominal changes were found in single knockout mice, contractility and passive properties were significantly compromised in α7-integrin double knockout mice. Our results suggest that DGC and α7ß1-integrin complexes may compensate each other to maintain normal skeletal muscle function. α7ß1-Integrin upregulation may hold promise to treat not only histological, but also physiological, defects in DMD.