Segmental fibre type composition of the rat iliopsoas muscle.

The iliopsoas of the rat is composed of two muscles - the psoas major muscle and the iliacus muscle. The psoas major muscle arises from all the lumbar vertebrae and the iliacus muscle from the fifth and sixth lumbar vertebrae and ilium. Their common insertion point is the lesser trochanter of the femur, and their common action is the lateral rotation of the femur and flexion of the hip joint. Unlike humans, the rat is a quadruped and only occasionally rises up on its hind legs. Therefore, it is expected that the fibre type composition of the rat iliopsoas muscle will be different than that of humans. The iliopsoas muscle of the rat is generally considered to be a fast muscle. However, previous studies of the fibre type composition of the rat psoas muscle showed different results. Moreover, very little is known about the composition of the rat iliacus muscle. The aim of our study was to examine the fibre type composition of the rat iliopsoas muscle in order to better understand the complex function of the listed muscle. The psoas major muscle was examined segmentally at four different levels of its origin. Type I, IIA, IIB and IIX muscle fibres were typed using monoclonal antibodies for myosin heavy chain identification. The percentage of muscle fibre types and muscle fibre cross-sectional areas were calculated. In our study we showed that in the rat iliopsoas muscle both the iliacus and the psoas major muscles had a predominance of fast muscle fibre types, with the highest percentage of the fastest IIB muscle fibres. Also, the IIB muscle fibres showed the largest cross-sectional area (CSA) in both muscles. As well, the psoas major muscle showed segmental differences of fibre type composition. Our results showed changes in percentages, as well as the CSAs of muscle fibre types in cranio-caudal direction. The most significant changes were visible in type IIB muscle fibres, where there was a decrease of percentages and the CSAs from the cranial towards the caudal part of the muscle. From our results it is evident that the rat iliopsoas muscle has a heterogeneous composition and is composed of all four muscle fibre types. Primarily, it is a fast, dynamic muscle with a predominance of fast type IIB muscle fibres with the largest CSAs. The composition of the rat psoas major muscles changes in a cranio-caudal direction, thus pointing to a more postural role of the caudal part of the muscle.

Reg3G gene expression in regenerating skeletal muscle and corresponding nerve.

INTRODUCTION: The Reg genes play a major role in the regeneration of various tissues; however, no reports have been published regarding expression of the Reg3G gene in skeletal muscle. In this study we investigated the expression of the Reg3G gene in regeneration of rat skeletal muscle and injured nerves. METHODS: We used 3 experimental models of muscle and nerve injury. RT-PCR and Western blot analysis were performed for detection of Reg3G in regenerating muscle and nerve. RESULTS: We found transcriptional activation of the Reg3G gene in the soleus and extensor digitorum longus muscles and in their corresponding nerves after both muscle and nerve injury in different time periods, respectively. CONCLUSIONS: The results suggest that the Reg3G gene plays a major role in communication between injured axons and muscle and may play a significant role in skeletal muscle and peripheral nerve regeneration.

MRI features of the psoas major muscle in patients with low back pain.

PURPOSE: The purpose was to investigate the changes of the psoas major muscles (PM) cross-sectional area (CSA) and fat infiltration in the PM and to investigate the association between the morphology of the PM and expression of the degenerative changes of lumbar spine in patients with low back pain (LBP). METHODS: T2-weighted scans for measurements of the CSA and analysis of fat infiltration were performed on 42 patients and 49 controls using a 1.5 Tesla MR system. For a quantitative analysis of fat tissue infiltration a 4-grade visual scale was used. RESULTS: Patients had bigger CSA of the PM than controls at the levels of L3/L4 and L4/L5 intervertebral disc (P < 0.05). Patients with apparent degenerative changes of the lumbar spine had smaller CSA of the PM compared to the patients without apparent changes at the levels of L3/L4 and L4/L5 (P < 0.05). At the levels of L4/L5 and L5/S1 patients with present Modic changes in the lumbar vertebral bodies showed smaller CSA of the PM compared to the patients without Modic changes (P < 0.05). However, CSA of the PM in the patients with degenerative changes of lumbar spine and Modic changes was still bigger than the one of the controls. At all analyzed levels correlation between CSAs of the PM and fat infiltration of the lumbar paraspinal muscles was negative. CONCLUSION: Results suggest increased activity of the PM in LBP patients but PM also remains active regardless of the presence of degenerative and Modic changes of the lumbar spine.

Segmental composition of the porcine iliopsoas muscle and influence of the body size and posture on the composition of the iliopsoas muscle.

The iliopsoas muscle (IPM) of the pig consists of the iliacus muscle (IM) and the psoas major muscle (PMM). Due to the differences in posture and size between animal species, the musculoskeletal system is subjected to different functional demands, which affects the morphological characteristics of the musculoskeletal system. The aim of this study was to determine the muscle fiber type composition in pigs IPM, as pigs are large quadrupeds that differ in body size and posture from humans and small mammals, and to determine the influence of body size and posture on the composition of IPM. Muscle samples were collected from the Pietrain Landrace pigs, a sample from IM and a samples at four segments of the PMM. Samples were analyzed with monoclonal antibodies specific for different isoforms of the myosin heavy chain. The percentages and cross-sectional area (CSA) of type I, IIA, and IIX/IIB muscle fibers were calculated. Our studies revealed that in pigs IPM, type IIX/IIB muscle fibers were predominant with the largest CSA. A decrease in the proportion of type IIX/IIB muscle fibers, an increase in type I and IIA muscle fibers, and a decrease in the CSA of all muscle fiber types from the cranial to the caudal part of the PMM were observed. The pig IPM has primarily a dynamic function. The function of the PMM in the cranio-caudal direction changes from a dynamic to a static role. Body size and posture influence the composition of the IPM.

Effect of hyperbaric oxygen treatment on myogenic transcriptional factors in regenerating rat masseter muscle.

Hyperbaric oxygen (HBO) treatment was shown to be beneficial as an additional treatment for ischemic muscles in crush injuries and ischemia-reperfusion injuries. The purpose of this study was to assess the influence of hyperbaric oxygen treatment on transcriptional myogenic factors during muscle regeneration. Those factors (MyoD, myf5, myogenin, mrf4) are essential for determination and differentiation of skeletal muscle tissue and together with several other factors control gene expression during myogenesis. The process of regeneration in rat masseter muscle was provoked with injection of local anesthetic bupivacaine hydrochloride. Following injection, the animals were treated once daily in hyperbaric chamber from one to ten days and than sacrificed. Immunohistochemical and Western blot analysis of frozen masseter muscle samples showed a transient upregulation of myoD and myogenin transcriptional factors in the muscles of hyperbaric oxygen treated rats and of rats that have not been treated after the injury. HBO treatment had no effect on the expression of MyoD and myogenin transcriptional factors in the regenerating rat masseter muscle.

Bone quality assessment in individuals of different age, gender and body constitution.

The concept of bone quality describes the sets of the characteristics of the osseous tissue that influence bone strength. The aim was to explore the influence of anthropometric parameters and age on the parameters of the bone architecture and bone mineral properties in the lumbar vertebral bone of men and women. Vertebral bone samples underwent bone histomorphometry, bone densitometry and atomic absorption spectrometry. Men have greater values of the bone volume and thicker bone trabeculae in relation to women, which indicates that vertebral bone architecture is better preserved in men than in women. Age is the best predictor of changes that affect bone architecture and bone mineral properties. Bone mineral density value and calcium concentration are both negatively predicted by age, but positively predicted by body mass index. Such result supports the opinion that low body mass index is associated with conditions of bone deficit such are osteopenia and osteoporosis.

Muscle loss in elderly.

Aging is associated with loss of skeletal muscle mass, strength and endurance. The aim of this study was to determinate age related changes in human muscles with different function and location in the body (vastus lateralis muscle and intercostal internus muscle). Our results suggest that age related muscle atrophy affect both human skeletal muscles. Also, the results showed the increase in percentage of muscle fibers with high oxidative activity during aging.

Immunohistochemical analysis of the human psoas major muscle with regards to the body side and aging.

The aim of our study was to explore the age related changes of the fibre type composition of the human psoas major muscle. Moreover, we wanted to compare the fibre type composition of the left and right muscle. Muscle samples were collected from 15 young and 15 old males. Type I, IIA and IIX muscle fibres were typed using myosin heavy chain identification. The serial transverse sections were analysed using a light microscope. Results of our study showed that the age-related atrophy affected all three fibre types. Type IIA fibres were affected most profoundly while type I fibres were affected most weakly. The percentage of the different fibre types did not change during aging. There were no differences in the fibre type composition between the left and right muscle. Human psoas major muscle undergoes normal aging changes with the atrophy of all three fibre types, whereas atrophy most profoundly affects type IIA fibres. No differences in the fibre type composition between the left and right muscle point to the equal engagement of both legs in normal everyday activities of human.

Properties of the celiac trunk--anatomical study.

Although anatomical properties and vessel variations of the celiac trunk are well explored in the literature, there is not so much information on the arterial diameters, and this data is important for surgical procedures and angiographic examinations. The aim of this study was to investigate properties of the celiac trunk in humans by using anatomical dissection. Ninety cadavers were dissected for the celiac trunk identification and arterial diameter measurements. The results of anatomical examination showed that in 72% of all cases the celiac trunk divides into the splenic artery and the common hepatic artery, while the left gastric artery arises as a first branch and had origin between aorta, all over the celiac trunk up to a bifurcation. From the 90 cadavers, 4 presented anatomical variations. Where normal anatomy was present, the mean length of the celiac trunk was 1.9 +/- 0.08 cm and its mean arterial diameter was 0.78 +/- 0.08 cm. The splenic artery had the largest diameter (0.61 +/- 0.05 cm) and the left gastric artery had the smallest diameter (0.38 +/- 0.03 cm). Our data represent original results about anatomical variations and arterial diameter of the celiac trunk and its main branches provided by anatomical dissection.

Fibre type composition of the human psoas major muscle with regard to the level of its origin.

The aim of our study was to explore the fibre type composition of the human psoas major muscle at different levels of its origin, from the first lumbar to the fourth lumbar vertebra, and to compare the muscle fibre size and distribution of different fibre types between levels with respect to its complex postural and dynamic function. Muscle samples were collected from 15 young males (younger than 35 years). Serial transverse sections (5 microm) of the samples were cut by cryomicrotome. Type I, IIA and IIX muscle fibres were typed using myosin heavy chain identification. The serial sections were analysed using a light microscope with a magnitude of 100x. The differences between measurements were evaluated using a repeated-measures anova and Scheffé test for post-hoc analysis. Our study showed that the human psoas major muscle was composed of type I, IIA and IIX muscle fibres. It had a predominance of type IIA muscle fibres, whereas type I muscle fibres had the largest cross-sectional area. Type IIX muscle fibres were present as a far smaller percentage and had the smallest cross-sectional area. Moreover, the fibre type composition of the psoas major muscle was different between levels of its origin starting from the first lumbar to the fourth lumbar vertebra. We conclude that the fibre type composition of the psoas major muscle indicated its dynamic and postural functions, which supports the fact that it is the main flexor of the hip joint (dynamic function) and stabilizer of the lumbar spine, sacroiliac and hip joints (postural function). The cranial part of the psoas major muscle has a primarily postural role, whereas the caudal part of the muscle has a dynamic role.

Anthropometric parameters as predictors for iliopsoas muscle strength in healthy girls and in girls with adolescent idiopathic scoliosis.

In this study iliopsoas muscle strength was measured by portable dynamometer and it was explored to what extent independent predictors (age, body weight, body height and body mass index) affect iliopsoas strength in healthy subjects and in subjects with adolescent idiopathic scoliosis. The study population was consisted of 183 girls (90 healthy girls and 93 girls with adolescent idiopathic scoliosis). Student t test analysis showed no differences in maximal voluntary isometric contraction between healthy girls and girls with scoliosis. Independent variables predicted significantly iliopsoas strength in healthy group (r=0.96, p<0.01) and in scoliosis group (r=0.94, p<0.001). Separate analysis with respect to types of scoliosis demonstrated that independent variables significantly predict iliopsoas strength in right thoracic (r=0.97, p<0.01), left thoracic (r=0.98, p=0.004), right thoracic lumbar (r=0.97, p<0.01) and left lumbar (r=0.96, p<0.01) scoliosis subgroups. In healthy girls iliopsoas strength was mostly predicted by body weight, followed by body height and body mass index. In girls with scoliosis body weigth was the strongest predictor of iliopsoas strength and was followed by curvature angle degree.

Reg IV protein and mRNA expression in different rat organs.

The Reg IV gene has been documented in the human colon, small intestine, stomach and pancreas. Expression of the Reg IV in different cell types has been associated with regeneration, cell growth and cell survival, cell adhesion and resistance to apoptosis. Since the distribution of the Reg IV protein in normal rat tissues is unknown, the aim of this study was to reveal the expression of the Reg IV protein in structurally and functionally different rat organs. The expression of Reg IV gene was analyzed by Western blot and reverse transcription-polymerase chain reaction. Immunohistochemistry was used to localize Reg IV protein. Reg IV protein was expressed in pancreas, stomach, small intestine, colon, brain, spleen, kidney and urinary bladder in two-month-old male Wistar rats. In addition, the expression of Reg IV mRNA by reverse transcription-polymerase chain reaction was confirmed. Our study provides detailed information about the expression and localization of Reg IV protein in different rat organs. These findings provide an evidence of Reg IV expression in different rat organs, which may help elucidate a potential role in growth and proliferation of different cells like other members of the Reg family genes which act as growth factors in the different organs.