Cardiovascular System and Muscle
George W. Casarett in Radiation Histopathology: Volume II, 2019
As a result of muscular activity, skeletal muscles increase in volume by enlargement of the existing fibers through an increase in the sarcoplasm. Large areas of damage in the skeletal muscle tissue are healed by replacement fibrosis, with the formation of scars. Smaller defects may be healed by regenerative replacement of lost or defective parts of muscle fibers from the remaining viable parts (nuclei and sarcoplasm) of these fibers. The viable nuclei in the defective fiber, together with their surrounding sarcoplasm, become separate cells (sarcoblasts or myoblasts) within the sarcoplasm; the ends of the fibers near the region go toward the damaged region as muscular buds; the sarcoblasts enlarge, multiply, digest the degenerate fibers, fuse in groups and form new fiber within the reticulum of the old fiber.
Mitochondrial Dysfunction and Its Impact on Oxidative Capacity of Muscle
Shamim I. Ahmad in Handbook of Mitochondrial Dysfunction, 2019
The interaction between two muscle cell’s compartments, contractile apparatus and “energy factories” of mitochondria depends on the oxidative capacity of muscle fibers. Type I and IIA fibers contain more mitochondria than IIB fibers (Seene et al. 2017a). There are large sized mitochondria tightly packed with cristae, and their small forms contain relatively few cristae (Seene et al. 2009; Seene and Kaasik 2013a). The intensive development of the mitochondrial apparatus in the recovery period after regular muscular activity vividly reflects the adaptive processes to muscle activity, which is intended to supply the increased energy requirements of muscle cells with higher oxidative capacity (Seene et al. 2007). Peripheral sarcoplasm, both type I and type IIA muscle fibers contain short canals of the granular sarcoplasmic reticulum as well as polyribosomes and several golgi complexes near the nucleus.
Skeletal Muscle
Manoj Ramachandran, Tom Nunn in Basic Orthopaedic Sciences, 2018
Skeletal muscle cells are of mesodermal origin. Mature cells are known as myotubes or muscle fibres. They are differentiated multinucleated cells formed by cytoplasmic fusion of immature mononucleated myoblasts. In muscle growth, these mononucleated precursor cells also fuse to the myotubes, adding to both the ends and the side of the cell. Muscle fibres vary in size and length between the sexes and between muscle groups. Individual fibres span the full length of the muscle they form. Fibres in muscles that have a precision requirement, such as the small muscles of the hand, tend to be smaller than in power muscles, such as the quadriceps, reflecting their contractile protein content. The fibre size is also related intimately to the innervation of the muscle, further illustrating the link between fibre size and function. Muscle fibres are bounded by a plasma membrane, the sarcolemma, and have a cytoplasm termed the sarcoplasm.
Metformin ameliorates cardiopulmonary toxicity induced by chlorpyrifos
Published in Drug and Chemical Toxicology, 2023
Ramtin Farhadi, Marzieh Daniali, Maryam Baeeri, Roham Foroumadi, Mahdi Gholami, Shokoufeh Hassani, Soheyl Mirzababaei, Hamed Haghi-Aminjan, Mona Navaei-Nigjeh, Mahban Rahimifard, Mohammad Abdollahi
Sections from the cardiac tissue of the control group were observed with typical structures with organized myofibrils and oval, vesicular nuclei. The same system was seen in metformin-treated groups (30, 60, and 120 mg/kg). However, in the CPF group, the highest degrees of muscle fiber disorganization and vacuolization were seen, as well as moderate necrosis, edema of the connective tissue, and congestion. In the CPF + Met 30 group, degeneration of muscle fibers was evident. The sarcoplasm in the CPF + Met 30 mg/kg was acidophilic, mild necrosis had occurred, and the architecture exhibited disorganization. The CPF + Met 60 group also revealed edema in the connective tissue. In CPF + Met 120 metformin group, the normal structure of the fiber was restored. The architecture of this group was closest to the groups that were treated only with metformin.
Histological and immunohistochemical study of the effect of ozone versus erythropoietin on induced skeletal muscle ischemia-reperfusion injury in adult male rats
Published in Ultrastructural Pathology, 2022
Magdy F. Gawish, Sally A. Selim, Alyaa A. Abd El-Star, Samah M. Ahmed
Ultrathin sections of skeletal muscle in the control showed normal architecture of muscle fibers with narrow inter-myofibrillar spaces. The sarcomere was in alignment with clear Z-line in the center of the I bands. Sarcoplasm contains numerous mitochondria located in the inter-myofibrillar space (Figure 7a). IR group showed injury of the muscular tissue in the form of fragmented fibers, irregular myofibrillar arrangement, cytoplasmic lysis with widened inter-myofibrillar spaces, and interrupted Z-lines (Figure 7b). Sarcoplasm contained variable-sized cytoplasmic vacuoles (Figure 7c) and swollen electron dense mitochondria with loss of their cristae (Figure 7d). Post-reperfusion ozone-treated group showed normal arrangement of the muscle fibers and normal pattern mitochondria except for wide inter-myofibrillar spaces (Figure 7e). Post-reperfusion EPO-treated group revealed regularly arranged myofibrils with narrow inter-myofibrillar spaces and normal mitochondrial pattern (Figure 7f). Recovering post-reperfusion without treatment group demonstrated myofibrils with some swollen electron dense mitochondria and variable-sized cytoplasmic vacuoles (Figure 7g). Other sections showed parts of myofibrils were invaded by fibroblasts and replaced by collagen fibers (Figure 7h).
Effects of Trans-Cinnamaldehyde on Reperfused Ischemic Skeletal Muscle and the Relationship to Laminin
Published in Journal of Investigative Surgery, 2021
Esra Pekoglu, Belgin Buyukakilli, Cagatay Han Turkseven, Ebru Balli, Gulsen Bayrak, Burak Cimen, Senay Balci
Ultrastructural changes of EDL skeletal muscle tissues were evaluated by a transmission electron microscope. EDL muscle cells were found to have normal morphological properties in the control group and treatment (IR + TCA) group. It was determined that the myofibrils in sarcoplasm had a regular sequence and that the sarcomere structure was protected. Also it was observed that the mitochondrion located between the myofibrils, the sarcoplasmic reticulum (SR) cisternae and other organelles were in a regular structure (Figure 6A,B). EDL muscle cells were generally found to have normal morphological properties in the group with I-R injury (IR + SF) (Figure 7A). Moreover, enlargement of SR cisternae (Figure 7B) and thinning of myofibrils (Figure 7C) were observed in some cells in the IR + SF group.