Rat Soleus Research Articles

Myosin Heavy-Chain Messenger Ribonucleic Acid (mRNA) Expression and Fibre Cross-Sectional Area in Masseter, Digastric, Gastrocnemius and Soleus Muscles of Young and Adult Rats.

Different demands on the muscles of mastication may influence their functional profile (size and distribution of muscle fibre types), which may change during growth and maturation, potentially influencing craniofacial growth. The aim of this study was to evaluate mRNA expression and cross-sectional area of masticatory muscle fibres compared with limb muscles in young and adult rats. Twenty-four rats were sacrificed at two different ages, namely 12 at 4 weeks (young) and 12 at 26 weeks (adult). The masseter, digastric, gastrocnemius and soleus muscles were dissected. Gene expression of myosin heavy-chain isoforms Myh7 (MyHC-I), Myh2 (MyHC-IIa), Myh4 (MyHC-IIb) and Myh1 (MyHC-IIx) in the muscles was measured using qRT-PCR RNA analysis, and immunofluorescence staining was performed to measure the cross-sectional area of different muscle fibre types. Different muscle types and ages were compared. Significant differences were found in the functional profile between masticatory and limb muscles. For the masticatory muscles, there was an increase in Myh4 expression with age, and this change was more intense for the masseter muscles, which also presented an increase in Myh1 expression, similarly to limb muscles. The fibre cross-sectional area of the masticatory muscles was generally smaller in young rats; however, this difference was less pronounced than in limb muscles.

Metformin Pre-Treatment as a Means of Mitigating Disuse-Induced Rat Soleus Muscle Wasting

Currently, no ideal treatment exists to combat skeletal muscle disuse-induced atrophy and loss of strength. Because the activity of AMP-activated protein kinase (AMPK) in rat soleus muscle is suppressed at the early stages of disuse, we hypothesized that pre-treatment of rats with metformin (an AMPK activator) would exert beneficial effects on skeletal muscle during disuse. Muscle disuse was performed via hindlimb suspension (HS). Wistar rats were divided into four groups: (1) control (C), (2) control + metformin for 10 days (C+Met), (3) HS for 7 days (HS), (4) metformin treatment for 7 days before HS and during the first 3 days of 1-week HS (HS+Met). Anabolic and catabolic markers were assessed using WB and RT-PCR. Treatment with metformin partly prevented an HS-induced decrease in rat soleus weight and size of slow-twitch fibers. Metformin prevented HS-related slow-to-fast fiber transformation. Absolute soleus muscle force in the HS+Met group was increased vs. the HS group. GSK-3β (Ser9) phosphorylation was significantly increased in the HS+Met group vs. the HS group. Metformin pre-treatment partly prevented HS-induced decrease in 18S+28S rRNA content and attenuated upregulation of calpain-1 and ubiquitin. Thus, pre-treatment of rats with metformin can ameliorate disuse-induced reductions in soleus muscle weight, the diameter of slow-type fibers, and absolute muscle strength.

Measurements of tendon length changes during stretch–shortening cycles in rat soleus

The muscle force attained during concentric contractions is augmented by a preceding eccentric contraction (the stretch–shortening cycle (SSC) effect). At present, tendon elongation is considered the primary mechanism. However, we recently found that the magnitude of the SSC effect was not different, even after removing the Achilles tendon. To resolve these discrepant results, direct measurement of changes in Achille tendon length is required. Therefore, this study aimed to elucidate the influence of tendon elongation on the SSC effect by directly measuring the changes in Achilles tendon length. The rat soleus was subjected to pure concentric contractions (pure shortening trials) and concentric contractions with a preceding eccentric contraction (SSC trials). During these contractions, the Achilles tendon length was visualized using a video camera. The muscle force attained during the concentric contraction phase in the SSC trial was significantly larger than that in the pure shortening trial (p = 0.022), indicating the existence of the SSC effect. However, the changes in Achilles tendon length were not different between trials (i.e., the magnitude of tendon shortening attained during the shortening phase was 0.20 ± 0.14 mm for the SSC trial vs. 0.17 ± 0.09 mm for the pure shortening trial), indicating that the observed SSC effect is difficult to be explained by the elastic energy stored in tendons or muscle–tendon interaction. In conclusion, the effect of tendon elongation on the SSC effect should be reconsidered, and other factors may contribute to the SSC effect.

New Findings: Hindlimb Unloading Causes Nucleocytoplasmic Ca2+ Overload and DNA Damage in Skeletal Muscle.

Disuse atrophy of skeletal muscle is associated with a severe imbalance in cellular Ca2+ homeostasis and marked increase in nuclear apoptosis. Nuclear Ca2+ is involved in the regulation of cellular Ca2+ homeostasis. However, it remains unclear whether nuclear Ca2+ levels change under skeletal muscle disuse conditions, and whether changes in nuclear Ca2+ levels are associated with nuclear apoptosis. In this study, changes in Ca2+ levels, Ca2+ transporters, and regulatory factors in the nucleus of hindlimb unloaded rat soleus muscle were examined to investigate the effects of disuse on nuclear Ca2+ homeostasis and apoptosis. Results showed that, after hindlimb unloading, the nuclear envelope Ca2+ levels ([Ca2+]NE) and nucleocytoplasmic Ca2+ levels ([Ca2+]NC) increased by 78% (p < 0.01) and 106% (p < 0.01), respectively. The levels of Ca2+-ATPase type 2 (Ca2+-ATPase2), Ryanodine receptor 1 (RyR1), Inositol 1,4,5-tetrakisphosphate receptor 1 (IP3R1), Cyclic ADP ribose hydrolase (CD38) and Inositol 1,4,5-tetrakisphosphate (IP3) increased by 470% (p < 0.001), 94% (p < 0.05), 170% (p < 0.001), 640% (p < 0.001) and 12% (p < 0.05), respectively, and the levels of Na+/Ca2+ exchanger 3 (NCX3), Ca2+/calmodulin dependent protein kinase II (CaMK II) and Protein kinase A (PKA) decreased by 54% (p < 0.001), 33% (p < 0.05) and 5% (p > 0.05), respectively. In addition, DNase X is mainly localized in the myonucleus and its activity is elevated after hindlimb unloading. Overall, our results suggest that enhanced Ca2+ uptake from cytoplasm is involved in the increase in [Ca2+]NE after hindlimb unloading. Moreover, the increase in [Ca2+]NC is attributed to increased Ca2+ release into nucleocytoplasm and weakened Ca2+ uptake from nucleocytoplasm. DNase X is activated due to elevated [Ca2+]NC, leading to DNA fragmentation in myonucleus, ultimately initiating myonuclear apoptosis. Nucleocytoplasmic Ca2+ overload may contribute to the increased incidence of myonuclear apoptosis in disused skeletal muscle.

The Maintenance of AMPK Activity Eliminates Abnormally Accelerated Differentiation of Primary Myoblasts Isolated from Atrophied Rat Soleus Muscle

Mechanical unloading of skeletal muscles leads to the development of atrophic processes and a decrease in the total number of satellite cells (SCs) that are involved in muscle regeneration. In vitro studies revealed an increased differentiation of myoblasts derived from rat soleus muscle after an unloading-induced decrease in AMP-activated protein kinase (AMPK). AMPK is necessary for the activation of SCs and also participates in the regulation of myoblast proliferation and differentiation. It can be assumed that a decrease in the activity of AMPK after mechanical unloading can contribute to the acceleration of myoblast differentiation. The main purpose of this study was to elucidate a possible role of AMPK in the regulation of differentiation of myoblasts isolated from rat soleus muscle after mechanical unloading. To test this hypothesis, a specific AMPK activator, AICAR, was used to prevent a decrease in AMPK activity during differentiation of myoblasts isolated from rat soleus muscle after 7-day unloading. Immunocytochemistry, PCR-RT and Western blotting were used to assess changes during myoblast differentiation. In differentiating myoblasts derived from the unloaded soleus muscle there was a significant decrease in AMPK (Thr172) and ACC (Ser 79) phosphorylation levels, an increase in myotube differentiation index, myoblast fusion factors and the expression of myogenic regulatory factors (MRF). Furthermore, there was a decrease in the expression of slow myosin heavy chains (MyHC) and an increase in the expression of fast MyHC isoforms. AICAR treatment of differentiating myoblasts obtained from the unloaded soleus muscle prevented a decrease in AMPK and ACC phosphorylation, returned the expression levels of MRF and fast isoforms of MyHC to the control levels as well as maintained the expression of slow MyHC. Thus, abnormally accelerated differentiation of myoblasts isolated from atrophied rat soleus muscle can be compensated by maintaining the control levels of AMPK activity using AICAR.

Role of L-Type Calcium Channels in the Increased Fatigue of Rat Soleus Muscle under Functional Unloading

Excessive long-term accumulation of calcium ions in the myoplasm of skeletal muscles can negatively affect mitochondria and lead to muscle dysfunction. The aim of our study was to identify the role of L-type calcium channels in the development of increased fatigue rat soleus muscle under functional unloading. Young male Wistar rats were divided into three groups of 8 animals each: the vivarium control group (C), the group subjected to hind limb unloading for 7 days (7HS) and the group with 7 days of hindlimb unloading with daily intraperitoneal injections of nifedipine (7 mg/kg body weight). The administration of nifidipine during hindlimb unloading prevented the upregulation of calcium-dependent phosphorylation of calcium-calmodulin kinase II (CaMK II), prevented the increase in fatigue and contributed to the preservation of mitochondrial proteins, DNA and mRNA expression of a number of genes that regulate mitochondrial biogenesis.

AMPK Phosphorylation Impacts Apoptosis in Differentiating Myoblasts Isolated from Atrophied Rat Soleus Muscle

Regrowth of atrophied myofibers depends on muscle satellite cells (SCs) that exist outside the plasma membrane. Muscle atrophy appears to result in reduced number of SCs due to apoptosis. Given reduced AMP-activated protein kinase (AMPK) activity during differentiation of primary myoblasts derived from atrophic muscle, we hypothesized that there may be a potential link between AMPK and susceptibility of differentiating myoblasts to apoptosis. The aim of this study was to estimate the effect of AMPK activation (via AICAR treatment) on apoptosis in differentiating myoblasts derived from atrophied rat soleus muscle. Thirty rats were randomly assigned to the following two groups: control (C, n = 10) and 7-day hindlimb suspension (HS, n = 20). Myoblasts derived from the soleus muscles of HS rats were divided into two parts: AICAR-treated cells and non-treated cells. Apoptotic processes were evaluated by using TUNEL assay, RT-PCR and WB. In differentiating myoblasts derived from the atrophied soleus, there was a significant decrease (p < 0.05) in AMPK and ACC phosphorylation in parallel with increased number of apoptotic nuclei and a significant upregulation of pro-apoptotic markers (caspase-3, -9, BAX, p53) compared to the cells derived from control muscles. AICAR treatment of atrophic muscle-derived myoblasts during differentiation prevented reductions in AMPK and ACC phosphorylation as well as maintained the number of apoptotic nuclei and the expression of pro-apoptotic markers at the control levels. Thus, the maintenance of AMPK activity can suppress enhanced apoptosis in differentiating myoblasts derived from atrophied rat soleus muscle.

The Maintenance of AMPK Activity Eliminates Abnormally Accelerated Differentiation of Primary Myoblasts Isolated from Atrophied Rat Soleus Muscle

The Maintenance of AMPK Activity Eliminates Abnormally Accelerated Differentiation of Primary Myoblasts Isolated from Atrophied Rat Soleus Muscle

Role of L-Type Calcium Channels in Increased Fatigue of the Rat Soleus Muscle under Functional Unloading

Role of L-Type Calcium Channels in Increased Fatigue of the Rat Soleus Muscle under Functional Unloading

Knee movements cause changes in the firing behaviour of muscle spindles located within the mono-articular ankle extensor soleus in the rat.

We recently showed that within an intact muscle compartment, changing the length of one muscle affects the firing behaviour of muscle spindles located within a neighbouring muscle. The conditions tested, however, involved muscle lengths and relative positions that were beyond physiological ranges. The aim of the present study was to investigate the effects of simulated knee movements on the firing behaviour of muscle spindles located within rat soleus (SO) muscle. Firing from single muscle spindle afferents in SO was measured intra-axonally for different lengths (static) and during lengthening (dynamic) of the lateral gastrocnemius and plantaris muscles. Also, the location of the spindle within the muscle was assessed. Changing the length of synergistic ankle plantar flexors (simulating different static knee positions, between 45 and 130°) affected the force threshold, but not the length threshold, of SO muscle spindles. The effects on type II afferents were substantially (four times) higher than those on type IA afferents. Triangular stretch-shortening of synergistic muscles (simulating dynamic knee joint rotations of 15°) caused sudden changes in the firing rate of SO type IA and II afferents. Lengthening decreased and shortening increased the firing rate, independent of spindle location. This supports our prediction that the major point of application of forces exerted by connections between adjacent muscles is at the distal end of SO. We conclude that muscle spindles provide the CNS with information about the condition of adjacent joints that the muscle does not span.

Force potentiation during eccentric contractions in rat skeletal muscle.

Postactivation potentiation refers to an acute enhancement of contractile properties following muscle activity. Previously, the effects of prior muscle activation on eccentric force at tetanic activation frequencies have only been sparsely reported. This paper aimed to study acute activity-induced effects on eccentric force of slow and fast-twitch muscles and characterize them in relation to postactivation potentiation. We elicited eccentric contractions in isolated rat extensor digitorum longus and soleus muscles by actively lengthening muscles at a constant velocity. We assessed contractile properties by measuring force over shortly interspaced, identical eccentric, and isometric contractions. We then analyzed stretch force, isometric peak force, rate of force development, and relaxation times. Finally, we compared the time courses for the development and cessation of changes in stretch force to known features of postactivation potentiation. In extensor digitorum longus, muscles stretch force consistently increased in a contraction-to-contraction manner by up to 49% [95% confidence interval (CI): 35-64%] whereas isometric peak force simultaneously showed minor declines (8%, 95% CI: 5-10%). The development and cessation of eccentric force potentiation coincided with the development of twitch potentiation and increases in rate of force development. In soleus muscles we found no consistent eccentric potentiation. Characterization of the increase in eccentric force revealed that force only increased in the very beginning of an active stretch. Eccentric force at tetanic activation frequencies potentiates substantially in extensor digitorum longus muscles over consecutive contractions with a time course coinciding with postactivation potentiation. Such eccentric potentiation may be important in sport performance.NEW & NOTEWORTHY Force during eccentric contractions can increase to a magnitude that may have profound consequences for our understanding of skeletal muscle locomotion. This increase in eccentric force occurs over consecutive, shortly interspaced, tetanic contractions in rat extensor digitorum longus muscles-not in rat soleus muscles-and coincides with well-known traits of postactivation potentiation. Eccentric force potentiation may significantly enhance muscle performance in activities involving stretch-shortening cycles.

Interpreting equatorial X-ray diffraction patterns from striated muscle with multiscale modeling.

Small-angle X-ray diffraction is the tool of choice to obtain nm-scale structural information from striated muscle under near-physiological conditions. A critical barrier to progress has been the lack of generally applicable computational tools for modeling these X-ray diffraction patterns, limiting our ability to extract all the structural information potentially available. We addressed this need by extending the spatially explicit simulation platform MUSICO to predict equatorial fiber X-ray diffraction patterns from skeletal muscle. Electron densities for thin filaments with bound crossbridges were calculated using PDB structures of myosin S1, actin, tropomyosin, troponin and analogous nebulin structure derived from tropomyosin PDB. Thick filament backbone densities were constructed based on the Squire 1973 model incorporating “ribbon motifs” from a high-resolution cryo-EM structure of the Lethocerus thick filament. Titin and myosin S2 regions were constructed as cylindrical rings of density shells. Myosin heads in an ordered “parked state” were positioned in a shell close to the thick filament backbone with any disordered myosin heads distributed in a shell extending out to actin. X-ray diffraction patterns were calculated from sub-system motifs consisting of 1 thick filament and two thin filaments by evaluating the Fourier transform of this object at the reciprocal hexagonal lattice positions. Intensities were averaged over the 500 thick filaments and 1000 thin filaments used in simulation. Using this approach, we found that we could recapitulate 7 independent experimental intensities (out to the 4,0 reflection) from relaxed rat soleus and EDL muscle by varying only the proportion of heads in the parked state and a temperature factor type disorder term. Fits to contracting data could be achieved by adjusting only the temperature factor term and the number of force-producing crossbridges predicted by MUSICO to match the force levels observed experimentally.

Effects of Resistance Exercise on Slow-Twitch Soleus Muscle of Infarcted Rats.

Three months after MI induction, male Wistar rats were assigned to Sham (n = 14), MI (n = 9), and resistance exercised MI (R-MI, n = 13) groups. The rats trained three times a week for 12 weeks on a climbing ladder. An echocardiogram was performed before and after training. Protein expression of the insulin-like growth factor (IGF)-1/protein kinase B (Akt)/rapamycin target complex (mTOR) pathway was analyzed by Western blot. Mortality rate was higher in MI than Sham; in the R-MI group, mortality rate was between that in MI and Sham and did not differ significantly from either group. Exercise increased maximal load capacity without changing cardiac structure and left ventricular function in infarcted rats. Infarction size did not differ between infarcted groups. Catalase activity was lower in MI than Sham and glutathione peroxidase lower in MI than Sham and R-MI. Protein expression of p70S6K was lower in MI than Sham and p-FoxO3 was lower in MI than Sham and R-MI. Energy metabolism did not differ between groups, except for higher phosphofrutokinase activity in R-MI than MI. Resistance exercise is safe and increases muscle strength regardless structural and functional cardiac changes in myocardial-infarcted rats. This exercise modality attenuates soleus glycolytic metabolism changes and improves the expression of proteins required for protein turnover and antioxidant response.

1146 SLEEP DEPRIVATION INDUCES AGEING-LIKE CHANGES IN ANTIGRAVITY MUSCLES OF YOUNG ADULT MALE WISTAR RATS

Abstract Introduction Poor muscle health is associated with a series of chronic and metabolic conditions that are prevalent in individuals who chronically experience poor-quality sleep. But there is no study deciphering the role of sleep deprivation on muscle ageing. Therefore, in the present study we have measured the ultrastructure, histopathology, and oxidative stressors in soleus muscle of wistar rat after sleep deprivation and recovery sleep. Material and Methods The experiments were conducted in 18 rats of three groups. Group I rats had normal sleep wake cycle, Group II rats were subjected to 24 h sleep deprivation (SD) by gentle handling method1 and Group III rats had recovery sleep after 24 h SD. At the end of the sleep, sleep deprivation and recovery period, soleus muscle tissue was collected for ultrastructural, histological and oxidative stress markers. Oxidative damage was assessed by lipid peroxidation, catalase activity, reduced glutathione and nuclear labelling of 8-OHdG. The study was conducted as per the guidelines of the Institutional Animal Ethics Committee (960/IAEC/16). Results The data demonstrated that SD leads to ultrastructural changes in soleus muscle which includes sarcolemmal and mitochondrial alterations. In case of histopathological and histomorphological changes there was signs of tissue degeneration, inflammatory infiltrate in type I fibres and muscle atrophy was observed in soleus muscles. There was significant increase in level of 8-OHdG (p=0.02) and malondialdehyde in 24h SD (p=0.02) than control and recovery sleep groups. Moreover, the catalase activity and reduced glutathione level was significantly decreased in 24h SD group (p≤0.02) than control and recovery sleep. Conclusion 24hr sleep deprivation leads to an ageing like state in the skeletal muscle, which was recovered after sleep rebound.

Alleviative effects of α-lipoic acid on muscle atrophy via the modulation of TNF-α/JNK and PI3K/AKT pathways in high-fat diet and streptozotocin-induced type 2 diabetic rats.

Diabetes mellitus (DM) is often accompanied by clinical complications such as sarcopenia. Previous studies have indicated that oxidative stress and insulin resistance (IR) are highly associated with the pathogenesis of diabetic myopathy. α-lipoic acid (ALA), a potent biological antioxidant, exists abundantly in a variety of plants and vegetables. This study aimed to investigate the ameliorative effect of ALA on muscle atrophy in type 2 diabetic rats induced by high-fat diet feeding (HFD) plus streptozotocin (STZ) injection. The HFD/STZ-induced diabetic rats were orally administered 50, 100, or 200 mg/kg body weight ALA once a day for 13 weeks. The results showed that ALA at the tested concentrations significantly increased the soleus muscle mass and muscle fibers in diabetic rats. Proinflammatory cytokines, such as tumor necrosis factor (TNF)-α, were found to decrease in both the serum and muscle of ALA-treated diabetic rats. ALA significantly reduced the protein-expression levels of phosphorylated c-Jun N-terminal kinase (pJNK)/JNK, forkhead box O3 (FOXO3), and muscle ring-finger protein-1 (Murf1); whereas, it enhanced the protein-expression levels of phosphoinositide 3-kinase (PI3K), phosphorylated protein kinase B (pAKT)/AKT, myogenin determination gene D (MyoD), the mechanistic target of rapamycin (mTOR), and myosin heavy chain (MyHC) in the soleus muscle of diabetic rats. The results from this study suggested that ALA treatment may preserve soleus muscle mass, alleviate muscle atrophy by suppressing the TNF-α/JNK pathway, and ameliorate the PI3K/AKT pathway in HFD/STZ-induced type 2 diabetic rats.

Acute effects of a single moderate-intensity exercise bout performed in fast or fed states on cell metabolism and signaling: Comparison between lean and obese rats

AimsAlthough the benefits of exercise can be potentiated by fasting in healthy subjects, few studies evaluated the effects of this intervention on the metabolism of obese subjects. This study investigated the immediate effects of a single moderate-intensity exercise bout performed in fast or fed states on the metabolism of gastrocnemius and soleus of lean and obese rats. Main methodsMale rats received a high-fat diet (HFD) for twelve weeks to induce obesity or were fed standard diet (SD). After this period, the animals were subdivided in groups: fed and rest (FER), fed and exercise (30 min treadmill, FEE), 8 h fasted and rest (FAR) and fasted and exercise (FAE). Muscle samples were used to investigate the oxidative capacity and gene expression of AMPK, PGC1α, SIRT1, HSF1 and HSP70. Key findingsIn relation to lean animals, obese animals' gastrocnemius glycogen decreased 60 %, triglycerides increased 31 %; glucose and alanine oxidation decreased 26 % and 38 %, respectively; in soleus, triglycerides reduced 46 % and glucose oxidation decreased 37 %. Exercise and fasting induced different effects in glycolytic and oxidative muscles of obese rats. In soleus, fasting exercise spared glycogen and increased palmitate oxidation, while in gastrocnemius, glucose oxidation increased. In obese animals' gastrocnemius, AMPK expression decreased 29 % and SIRT1 increased 28 % in relation to lean. The AMPK response was more sensitive to exercise and fasting in lean than obese rats. SignificanceExercise and fasting induced different effects on the metabolism of glycolytic and oxidative muscles of obese rats that can promote health benefits in these animals.

The effect of aerobic training and curcumin supplementation on the expression of IGF-1 gene in muscle rat

Background: The purpose of this research was to investigate the effect of four weeks of moderate aerobic training and nanocurcumin supplementation on IGF-1 gene expression and its receptor in the soleus muscle of rats. Materials and Methods: 32 male Wistar rats, approximately eight weeks old, with a weight range of 200±10 grams, were prepared and kept for one week under standard conditions of light, temperature, and humidity. Rats were randomly divided into 4 groups of 8 series: healthy control group, aerobic training group, nanocurcumin group and aerobic training + nanocurcumin group. The training protocol was for 4 weeks, 5 days a week, in the first week, 20 minutes of activity with a speed of 18 meters per minute, and finally in the 4th week, it reached 35 minutes of activity with a speed of 20 meters per minute. Nanocurcumin supplement was also used for each animal at 80 mg / kilogram of body weight. One-way analysis of variance and Bonferroni's post hoc test was used at the significance level (P<0.05). Results: The results showed an increase in IGF-1 and IGF-1R gene expression levels in the soleus muscle in all groups compared to the control group. Conclusion: The combination of training and nanocurcumin supplementation probably increases the antioxidant capacity of the body and causes a greater increase in the expression of the IGF-1 gene and IGF-1R in skeletal muscles, which indicates more anabolic effects.

ДИФФЕРЕНЦИРОВКА МИОБЛАСТОВ, ВЫДЕЛЕННЫХ ИЗ M. SOLEUS КРЫСЫ ПОСЛЕ АНТИОРТОСТАТИЧЕСКОГО ВЫВЕШИВАНИЯ, СОПРОВОЖДАЕТСЯ ДЕФОСФОРИЛИРОВАНИЕМ P27KIP1 И УСИЛЕНИЕМ АПОПТОЗА

Apoptosis and its control during differentiation of primary myoblasts isolated from rat soleus muscle after 7-d tail suspension were investigated. Primary myoblasts were first subjected to myogenic differentiation. TUNEL labeling of double-strand DNA breaks was applied to detect apoptotic cells during myoblast differentiation. Western blot was used to determine the apoptosis markers and a number of signaling molecules, i.e. protein BAX, activated caspase-3, phospho-AMPK (Thr172), phospho-AKT (Ser 437), phospho-p27Kip1 (Thr198), phospho-p27Kip1 (Thr157). PCR analysis was used to investigate the expression of pro-apoptotic markers in myoblasts. The investigation showed enhancement of apoptosis as well as АМРК and p27Kip1 dephosphorylation in the process of differentiation of myoblasts taken from m. soleus of tail-suspended rats.

Effect of Sijunzi Decoction on the Myonuclear Domain of Rat Soleus in Spleen Qi Deficiency

Effect of Sijunzi Decoction on the Myonuclear Domain of Rat Soleus in Spleen Qi Deficiency

The effect of melatonin on rat soleus muscle treated with carbon tetrachloride

Antioxidants are known to restrains various tissue damage caused by the administration of carbon tetrachloride (CCl4). This study examined whether melatonin (MEL), a molecule known to have antioxidant properties, has a protective effect on the rat soleus muscle, where toxic damage is caused by the application of CCl4. In the study, eighteen albino-type male Wistar rats were used and divided into three groups as Control Group (group 1), CCl4 group (group 2) and CCl4 + MEL group (group 3). End of the 12 weeks, blood samples were taken as intracardiac from the rats under ketamine/rompun anesthesia, and the soleus muscles of the rats were removed. Tissue samples were subjected to routine preparation procedures for light microscopy. Sections 5 µm thick taken and stained with hematoxylin-eosin (HE) for histopathological examinations and Masson’s Trichrome stain for fibrosis formations. In conclusion, the CCl4 group displayed muscular hypertrophy, fiber orientation dysfunction and atrophy in some areas. In addition, fibrosis was spotted around the venous and nerve plexuses. In contrast to the CCl4 group, the melatonin group displayed no fibrosis and maintained tissue integrity. Therefore, when comparing CCl4+MEL and CCl4 groups, it was observed that melatonin had a stabilizing or even curative effect on the injuries.