الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
Aging is characterized by a decrease in the physical function in the daily activities resulting in reduced quality of life. Aging is characterized by the loss in the muscle mass and strength (sarcopenia). Age-related changes in the muscle are thought to depend on a number of changes including mitochondrial production of reactive oxygen species and changes in gene expression that resulted from changes of muscle-specific micro-RNAs. Therefore, the purpose of this study was to investigate the biochemical, histological and molecular changes in the skeletal muscle with aging. Both male and female mice were used in the present study. The mice of 15 days were obtained and divided into five groups in which each has 10 males and 10 females, respectively. The mice were raised at the laboratory for 1, 3, 6, 9 and 15-month old, respectively. All mice were fed with a laboratory regular diet (Protein 25%, Fat 5.0%, Carbohydrate 47.5%, Crude fiber 5.3%, Ash 7.0%) and were housed in cages in controlled environmental conditions (22- 25 ᵒC), with a 12-12 hours light-dark cycle. Materials and methods At the previously determined age, the mice were sacrificed and soleus muscles were collected from each group under strict hygienic conditions to minimize the contamination or autolysis of the samples. Then, quickly frozen in liquid nitrogen before storing at –80 ᵒC to be used for micro-RNA extraction and for biochemical analysis. The samples which used for histological study were preserved in 10% neutral buffered formalin for 12 hours. Biochemical investigations The activities of reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) and Malondialdehyde (MDA) level were measured. Histological investigations The preserved soleus muscles in 10% neutral buffered formalin were embedded in paraffin. Sections of 5µm were cut, deparaffinized, hydrated and were stained with haematoxylin and eosin to clarify the histological changes in the muscle fibers. Molecular investigations The difference expression of the muscle specific micro-RNAs, primiR- 1-1, pri-miR-1-2, pri-miR-133a1, pri-miR-133a2 and pri-miR-206 were investigated. Results Biochemical changes The results showed: 1- A significant reduction (p ≤ 0.05) in the activities of GSH, SOD and CAT in both male and female mice with aging, respectively. 2- A significant increase (p ≤ 0.05) in MDA level in both male and female mice with aging, respectively. 3- A non-significant difference (p ≥ 0.05) in GSH, SOD, CAT and MDA levels between male and female mice at the 1st, 3rd, 6th, 9th and 15th month of age, respectively.