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Beneficial effects of voluntary over forced exercise on skeletal muscle structure and myokines’ expression

100%

Eldomiaty M. A. , Elayat A. , Ali S. , Algaidi S. , Elnaggar M.

Folia Morphologica

2020

tom 79

nr 2

Background: Myokines, a group of small proteins — mainly cytokines, are released by myocytes during muscular contraction and proved to have many biological effects locally or at systemic levels. The main objective was to study the morphological alterations and myokines expression in rat gastrocnemius muscle following forced compared to voluntary muscle contraction. Materials and methods: Thirty-six adult male Wistar rats were divided into three groups: control, voluntary exercise and forced swimming regimen. The experiment last for 3 weeks. The weight of rats and serum corticosterone levels were recorded. The gastrocnemius muscle samples were processed for histological and immunohistochemical study of different myokines. Results: The mean weight of rats showed no statistical difference between groups. Corticosterone level significantly increased after forced exercise. Voluntary exercise muscle fibres appeared hypertrophied with prominent transverse banding and dominating satellite cells. Forced exercise muscle showed atrophied widely spaced muscle fibres and inflammatory cell infiltrate. Voluntary exercise significantly increased optic density of interleukin 6, macrophage inhibitory and brain derived neurotrophic factors, whereas the forced exercise group showed significant decrease in their optic densities. The optic density of vascular endothelial growth factor significantly decreased in the forced exercise group. Forced exercise could be harmful to the skeletal muscle fibres and it decreases the secretion of important myokines. Further, forced exercise significantly increases the serum corticosterone level. Conclusions: The use of exercise for the attainment of healthy life style or in psycho- or neuro-therapy should follow a thoroughly studied programme for welfare of human health. (Folia Morphol 2020; 79, 2: 350–358)

Structural Transition in SrZnO Laser Pulse Deposited Alloy

72%

Albrithen H. A. , Elnaggar M. , Ozga K. , Szota M. , Alahmed Z. A. , Alanazi A. Q. , Alshahrani H. , Alfaifi E. , Djouadi M. A. , Labis J. P.

Archives of Metallurgy and Materials

2017

tom Vol. 62, iss. 1

211--216

We have discovered a structural transition for the SrZnO alloy films from a wurtzite to a rock-salt structure, leading to a reduction in the (112̲0)/(0001) surface energy ratio. The films were grown by pulsed laser deposition using different SrO ratios, x. We have revealed that growth at a higher temperature, 750°C, resulted in a sharp 0002 peak at a low SrO content (5%), whereas growth at a higher SrO content (10%) resulted in a non-crystalline film with minute crystallites with a (112̲0) orientation. Generally the crystallinity decreased as the SrO content increased. No results obtained for the crystalline films showed any orientation of significant peaks besides the peak attributed to the (0001) plane, suggesting epitaxial growth. Optical measurements showed difference in transmission widows of alloys with different SrO percentage, and this was correlated to SrO influence on growth mode as indicated by scanning electron imaging. The studied SrZnO films, with SrO/(SrO + ZnO) ≤ 0.25, were grown by pulsed laser deposition using different SrO ratios, x. The effects of temperature and oxygen pressure during growth on the films’ structural properties were investigated. XRD results indicate that the film crystallinity was improved as the temperature and O2 pressure increased up to 650°C and 0.5 Torr, respectively.