الفهرس 
Aim of the workOnly 14 pages are availabe for public view
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Abstract
Immobilization can occur as a consequence of injury, illness, surgery and reduced physical activity. Only within the last four decades, the physicians become increasingly aware of the harmful effects of immobilization e.g loss of muscle extensibility, reduction in muscle mass and intramuscular fibrosis, factors which result in great loss of muscle function.
Despite the fact that stretching exercises are commonly included in prevention and treatment of muscle atrophy, this physical therapy intervention is not successful in preventing disuse muscle atrophy early in the medical treatment of critically ill patients.
Although several potentially interesting therapeutic targets for preventing muscle atrophy have already been identified such as ghrelin, clenbuterol and testosterone, their clinical applications are limited because of concerns regarding potential side effects. So there is an obvious need for alternative safe inexpensive approaches.
Apple peel extract is a rich source of triterpenes and polyphenolic compounds. These groups of phytochemicals are well documented for their function as antioxidants and cell signaling pathway modulators. In addition, they present anabolic effects on the skeletal muscle.
The present study was performed to evaluate the immobilization induced changes in the skeletal muscle (soleus) and the ability of apple peel extract or/and stretching exercise to prevent these changes. All of these were based on biochemical, histological and immunohistochemical studies.
Materials and methods:
Seventy adult male albino rats were divided into seven groups, ten rats for each:- group I (Control group), rats fed on normal diet and kept without any treatment all over the experiment. group II (APE group), Rats received APE orally by gastric tube once daily for 3 weeks at a dose of 500 mg/kg/day. group III (Stretching group), rats’ left hindlimbs were maintained in a fully stretched position once a week for two weeks.
group IV (Immobilization group), Rats were anesthetized by diethyl ether inhalation then their left hindlimbs were immobilized in a shortened position for 2 successive weeks. group V (APE with immobilization), rats’ left hindlimbs were immobilized for 2 successive weeks in shortened position and received APE orally by gastric tube once daily for 3 weeks starting one week before hindlimb immobilization. group VI (Stretching with immobilization), rats’ left hindlimbs were immobilized in the shortened position, but once a week the immobilization was removed and their left hindlimbs were maintained in a stretched position for 40 min. group VII (APE and stretching with immobilization), rats received APE orally by gastric tube once daily for 3 weeks starting one week before immobilization. Their left hindlimbs were immobilized in the shortened position for 2 weeks, but once a week the immobilization was removed and their left hindlimbs were maintained in a stretched position for 40 min. After the stretching procedure, the left hindlimbs were immobilized again.
After the experiment, the body weights were calculated and blood samples were collected from the retro-orbital venous plexus for assessment of serum creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) levels. All Animals were
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anaesthetized lightly by diethyl ether inhalation and their left hindlimbs soleus muscles were dissected and excised. Assessment of malondialdehyde (MDA) and superoxide dismutase activity (SOD) activity was performed in muscle tissue. The absolute and relative soleus muscle weights were detected then muscle tissues were processed for histological studies. In addition, Immunohistochemical study was performed to detect desmin, Caspase-3 and MuRF-1.
The morphometric measurements were done for calculation of cross sectional area of muscle fibers, the percentage area of collagen fibers deposition as well as desmin, caspase-3 and MuRF-1 immunoreaction. Statistical analysis was done for all calculated parameters.
Results:
Non-significant difference between group I, II and III in the all examined parameters.
The present study showed a significant decrease in the body weight, absolute and relative soleus muscle weight of group IV in comparison with the control one. A significant increase in these parameters was detected in group V and VII with no significant changes in group VI.
Biochemical results revealed that LDH and CPK were significantly increased in group IV and decreased in group V and VII with no significant changes in group VI.
Oxidative stress parameters revealed a significant increase in MDA level and decrease in SOD activity in muscle tissue of group IV and a significant decrease in MDA level and increase in SOD activity in muscle tissue of group V and VII with no significant changes in group VI.
Histological study of soleus muscle sections from rats of the control group showed bundles of muscle fibers separated by perimysum, while the fibers were connected together by endomysium. The sarcoplasm of the muscle fibers appeared acidophilic and crossly striated. The nuclei were multiple, elongated and peripheral in position under the sarcolemma. At the electron microscopic level, the muscle sections of this group showed regular arrangement of myofibrils with alternating light (I) and dark (A) bands. Mitochondria were arranged in pairs around Z-line.
Histological study of soleus muscle sections from group IV showed wavy course of the muscle fibers and loss of transverse striation with fragmentation of the sarcoplasm and undulating sarcolemma. Obvious reduction in the CSA of muscle fibers was detected compared with the control group. Splitting of the muscle fibers and widening of the interstitial spaces in between were observed. Widening of perimysium associated with mononuclear cellular infiltration was noticed. Some of muscle fibers had dense pyknotic nuclei and others exhibited central nuclei. In addition, some muscle fibers showed areas of pale homogenous sarcoplasm which appeared as central core-like lesions.
At the electron microscopic level, the muscle sections of this group showed loss of sarcomere organization, indistinguishable A-band, I-band, and irregular and distorted Z-line. Marked aggregation of mitochondria of different size and shape in the subsarcolemmal and intermyofibrillar spaces was seen. Fusion of some mitochondria to form giant ones and vacuolation of others was observed. Electron-lucent vacuoles was also noticed.
SUMMARY AND CONCLUSION