Protective Effects Of Extract Of Ginkgo Biloba Against Ethaol-induced Oxidative Injury In Rat Muscles

Chronic alcoholic myopathy(CAM) is one of the most frequent causes of acquired skeletal myopathy in developed countries, which affects up 30%~60% of all alcohol misusers. Amount of alcohol poisoning patients in our country is becoming more and more in recent years. However, there is merely a few clinical reports about CAM in our country, and with respect to the research of the CAM pathogenesis and prophylaxis, it's still vacant essentially. The underlying mechanisms responsible for CAM are multiple factors, and only part of which is elucidated, studies have found that the imbalance of oxidation and anti-oxidation system affects the genesis and development of CAM. Oxidative stress is closely correlated with pathological proceeding in some myopathies. Theories of free radicals and lipid peroxidation during the metabolism of ethanol have been admitted by researchers. Increased oxidative stress can be induced by alcohol, which can cause atrophy of skeletal muscles. Compare with the genetic myopathy, CAM is the only treatable muscle disease. EGb is a standardized extract of Ginkgo biloba leaves containing 24% flavone glycosides(primarily quercetin, kaempferl and 6% terpene lactones). EGB has antioxidant properties EGB is mostly used to treat cardiac and cerebral vascular diseases as a free-radical scavenger and anti lipid peroxidation presently in China and Western countries. However, the application of EGB on CAM hasn't been reported domestically and abroadThus, with the increasing daily of the CAM patients, it has the important social significance to research the pathogenesis and treatment of CAM deeply.Objective: This study is designed to investigate whether EGB can protect against the oxidative injury in rat skeletal muscles of CAM and the possible mechanism responsible for it through obersavation of the change of oxidatant-antioxidant status and pathologic changes。Methods: (1)The rats were pretreated with EGB(48,96μg/g bw per day)before 56% ethanol gastric incubation and they are all feeding the same improved food with high fats and sufficient nutrients. (2) 10 weeks later, take the muscle of posterior limb, after separating the soleus,plantaris, to prepare the frozen section and muscular tissue homogenate of the each kind of muscle respectively. After it is confirmed to form the myopathy model by the histochemical stain, measure the activities of superoxide dismutase (SOD), glutathione peroxidase(GSH-Px) and the malondialdehyde(MDA) in the muscle specimens every group respectively by Spectrophotometer.Results:(1) Spectrophotometer method show: EGB-treated groups show a increase in the level of SOD,GSH-Px ( P < 0. 05)and a reduction in the level of MDA compared with CAM model group ( P < 0. 05) in the plantaris with major proportion of type II fibers, except for the low-dose EGB having no effect on the level of GSH-Px( P > 0. 05). Except for MDA level in EGB-treated shows a decrease compared with CAM model group (p < 0.05), the rest all show no obvious difference in the soleus with major proportion of typeⅠfibers. (2)The CAM rat shows typical pathological change in the skeletal muscle, such as myofibrosis,necrosis, the shape of the muscle fiber atrophy becomes triangle,strip or irregular, and the connective tissue among the muscle tissue become hyperplasia, and so on. EGB can attenuate the degree of pathological change.Conclusions: (1)Alcohol can induce the oxidative stress reaction, which results in the oxidant-antioxidant status imbalance in the skeletal muscle. (2)EGB possessed the protective effects from ethanol-induced muscle injury as a preventive antioxidant by improving antioxidant enzyme activity, and inhibiting lipid peroxidation reaction.