Electrical Stimulation-Based Twitch Exercise Suppresses Progression of Immobilization-Induced Muscle Fibrosis via Downregulation of PGC-1?/VEGF Pathway.

This study aimed to determine whether electrical stimulation-based twitch exercise is effective in inhibiting the progression of immobilization-induced muscle fibrosis. 19 Wistar rats were randomly divided into a control group (n=6), an immobilization group (n=6; with immobilization only), and a Belt group (n=7; with immobilization and twitch exercise through the belt electrode device, beginning 2 weeks after immobilization). The bilateral soleus muscles were harvested after the experimental period. The right soleus muscles were used for histological analysis, and the left soleus muscles were used for biochemical and molecular biological analysis. As a result, in the picrosirius red images, the perimysium and endomysium were thicker in both the immobilization and Belt groups compared to the control group. However, the perimysium and endomysium thickening were suppressed in the Belt group. The hydroxyproline content and alpha-SMA, TGF-beta1, and HIF-1alpha mRNA expressions were significantly higher in the immobilization and belt groups than in the control group. These expressions were significantly lower in the Belt group than in the immobilization group. The capillary-to-myofiber ratio and the mRNA expressions of VEGF and PGC-1alpha were significantly lower in the immobilization and belt groups than in the control group, these were significantly higher in the Belt group than in the immobilization group. From these results, Electrical stimulation-based twitch exercise using the belt electrode device may prevent the progression of immobilization-induced muscle fibrosis caused by downregulating PGC-1alpha/VEGF pathway, we surmised that this intervention strategy might be effective against the progression of muscle contracture. Keywords: Immobilization, Skeletal muscle, Fibrosis, Electrical stimulation-based twitch exercise, PGC-1alpha/VEGF pathway.

Skeletal Muscle Electrical Stimulation Prevents Progression of Disuse Muscle Atrophy via Forkhead Box O Dynamics Mediated by Phosphorylated Protein Kinase B and Peroxisome Proliferator-Activated Receptor gamma Coactivator-1alpha.

Although electrical muscle stimulation (EMS) of skeletal muscle effectively prevents muscle atrophy, its effect on the breakdown of muscle component proteins is unknown. In this study, we investigated the biological mechanisms by which EMS-induced muscle contraction inhibits disuse muscle atrophy progression. Experimental animals were divided into a control group and three experimental groups: immobilized (Im; immobilization treatment), low-frequency (LF; immobilization treatment and low-frequency muscle contraction exercise), and high-frequency (HF; immobilization treatment and high-frequency muscle contraction exercise). Following the experimental period, bilateral soleus muscles were collected and analyzed. Atrogin-1 and Muscle RING finger 1 (MuRF-1) mRNA expression levels were significantly higher for the experimental groups than for the control group but were significantly lower for the HF group than for the Im group. Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) mRNA and protein expression levels in the HF group were significantly higher than those in the Im group, with no significant differences compared to the Con group. Both the Forkhead box O (FoxO)/phosphorylated FoxO and protein kinase B (AKT)/phosphorylated AKT ratios were significantly lower for the Im group than for the control group and significantly higher for the HF group than for the Im group. These results, the suppression of atrogin-1 and MuRF-1 expression for the HF group may be due to decreased nuclear expression of FoxO by AKT phosphorylation and suppression of FoxO transcriptional activity by PGC-1alpha. Furthermore, the number of muscle contractions might be important for effective EMS.

The effects of wheel-running using the upper limbs following immobilization after inducing arthritis in the knees of rats.

This study investigated the effects of wheel-running using the upper limbs following immobilization after inducing arthritis in the knees of rats. Forty male Wistar rats (aged 8 weeks) divided into four groups randomly: arthritis (AR), immobilization after arthritis (Im), wheel-running exercise with the upper limbs following immobilization after arthritis induction (Im+Ex) and sham arthritis induction (Con). The knee joints of the Im and Im+Ex groups were immobilized with a cast for 4 weeks. In the Im+Ex group, wheel-running exercise was administered for 60 min/day (5 times/week). The swelling and the pressure pain threshold (PPT) of the knee joint were evaluated for observing the condition of inflammatory symptoms in affected area, and the paw withdraw response (PWR) was evaluated for observing the condition of secondary hyperalgesia in distant area. Especially, in order to evaluate histological inflammation in the knee joint, the number of macrophage (CD68-positive cells) in the synovium was examined. The expression of calcitonin gene-related peptide (CGRP) in the spinal dorsal horn (L2-3 and L4-5) was examined to evaluate central sensitization. The Im+Ex group showed a significantly better recovery than the Im group in the swelling, PPTs, and PWRs. Additionally, CGRP expression of the spinal dorsal horn (L2-3 and L4-5) in the Im+Ex group was significantly decreased compared with the Im group. According to the results, upper limb exercise can decrease pain in the affected area, reduce hyperalgesia in distant areas, and suppress the central sensitization in the spinal dorsal horn by triggering exercise-induced hypoalgesia (EIH).

Effects of a psychosocial intervention programme combined with exercise in community-dwelling older adults with chronic pain: A randomized controlled trial.

BACKGROUND: Although researchers have recommended exercise training and psychosocial intervention to manage chronic pain, an effective intervention for Japanese community-dwelling older adults with chronic pain has not been established. This randomized controlled trial examined whether exercise training combined with psychosocial intervention more effectively improves pain, psychological status and physical activity than does exercise training alone in this population. METHODS: We randomized 128 older adults with chronic pain to either an intervention group (n = 64) involving exercise training combined with psychosocial intervention, or a control group (n = 64) involving only exercise training. Exercise training comprised weekly 60-min sessions for 12 weeks. Psychosocial intervention involved changing participants' focus on pain using self-management education and cognitive behavioural therapy, and participants recorded their daily pain intensity and step counts. Pain intensity, psychological status and physical activity were assessed before and 12 weeks after the intervention. RESULTS: A time-by-group interaction emerged for psychological status (p = 0.003) and physical activity (p < 0.001), both favouring the intervention group. The intervention group also showed greater improvement in pain intensity at 12 weeks than did the control group (p = 0.007). CONCLUSIONS: Exercise training combined with psychosocial intervention improves key outcome indicators more effectively than does exercise training alone in older adults with chronic pain. SIGNIFICANCE: Although research has shown that combined exercise and psychosocial intervention is optimal for managing chronic pain, our study is the first, to the best of our knowledge, to test a specific intervention of this type in community-dwelling older adults with chronic pain in Japan.

The influence of aging on the effectiveness of heat stress in preventing disuse muscle atrophy.

This study examined the aging effect on disuse muscle atrophy prevention using heat stress. Wistar rats aged 7 and 60 weeks were divided into three groups as follows: control, immobilized (Im), and immobilized and heat stressed (ImH). Heat stress was given by immersing the hindlimbs in hot water (42 °C) for 60 min, once in every 3 days and the gastrocnemius (GAS) and soleus (SOL) muscles were extracted after 14 days. Muscle-fiber types were classified using ATPase staining. Heat shock protein 70 (HSP70) was assessed through Western blotting. In GAS muscle of both groups and SOL muscle of 7-week-old rats, the fiber diameter of each muscle type in the ImH group significantly increased compared with that in the Im group. However, this could not be observed in the SOL muscle of the 60-week-old rats. The increased percentage of type-I fibers and variability of types I and II muscle-fiber diameter were evident in the SOL muscle of the 60-week rats. HSP70 was significantly elevated in the ImH group compared with in the Im group in both muscle types of both age groups. Thus, effectiveness of heat stress in the prevention of disuse muscle atrophy appears unsatisfactory in aging muscle fibers.

Heat shock transcription factor 1-associated expression of slow myosin heavy chain in mouse soleus muscle in response to unloading with or without reloading.

AIM: The effects of heat shock transcription factor 1 (HSF1) deficiency on the fibre type composition and the expression level of nuclear factor of activated T cells (NFAT) family members (NFATc1, NFATc2, NFATc3 and NFATc4), phosphorylated glycogen synthase kinase 3α (p-GSK3α) and p-GSK3ß, microRNA-208b (miR-208b), miR-499 and slow myosin heavy chain (MyHC) mRNAs (Myh7 and Myh7b) of antigravitational soleus muscle in response to unloading with or without reloading were investigated. METHODS: HSF1-null and wild-type mice were subjected to continuous 2-week hindlimb suspension followed by 2- or 4-week ambulation recovery. RESULTS: In wild-type mice, the relative population of slow type I fibres, the expression level of NFATc2, p-GSK3 (α and ß), miR-208b, miR-499 and slow MyHC mRNAs (Myh7 and Myh7b) were all decreased with hindlimb suspension, but recovered after it. Significant interactions between train and time (the relative population of slow type I fibres; P = 0.01, the expression level of NFATc2; P = 0.001, p-GSKß; P = 0.009, miR-208b; P = 0.002, miR-499; P = 0.04) suggested that these responses were suppressed in HSF1-null mice. CONCLUSION: HSF1 may be a molecule in the regulation of the expression of slow MyHC as well as miR-208b, miR-499, NFATc2 and p-GSK3 (α and ß) in mouse soleus muscle.

Effect of continuous passive motion initiated after the onset of arthritis on inflammation and secondary hyperalgesia in rats.

This study investigated the effect of continuous passive motion (CPM) initiated after the onset of arthritis in rats. Rats were injected with 3 % kaolin/carrageenan in the knee joint and randomized to the control, immobilization (IM), or CPM group. The knee joints of the IM and CPM groups were immobilized with a cast for 56 days. In the CPM group, CPM exercise was administered for 60 min/day (6 times/week). Joint transverse diameter and pressure pain threshold (PPT) were assessed as indicators of inflammation, and paw withdrawal response (PWR) was assessed as indicator of secondary hyperalgesia. Central sensitization was analyzed by measuring calcitonin gene-related peptide (CGRP) expression levels in the spinal dorsal horn. In the CPM group, the PPT was significantly increased compared with the IM group from 14 to 35 days, and PWR was significantly decreased from 14 to 56 days. Additionally, CGRP expression in the super facial layer (I-II) of the spinal dorsal horn (L4-5) in the CPM group was significantly decreased compared with the IM group. Our study found the CPM initiated after the onset of arthritis promoted the recovery of inflammation and mitigated secondary hyperalgesia.

Heat treatment inhibits skeletal muscle atrophy of glucocorticoid-induced myopathy in rats.

The purpose of this study was to investigate the influence of heat treatment on glucocorticoid (GC)-induced myopathy. Eight-week-old Wistar rats were randomly assigned to the control, Dex, and Dex + Heat groups. Dexamethasone (2 mg/kg) was injected subcutaneously 6 days per week for 2 weeks in the Dex and Dex + Heat group. In the Dex + Heat group, heat treatment was performed by immersing hindlimbs in water at 42 °C for 60 min, once every 3 days for 2 weeks. The extensor digitorum longus muscle was extracted following 2 weeks of experimentation. In the Dex + Heat group, muscle fiber diameter, capillary/muscle fiber ratio, and level of heat shock protein 72 were significantly higher and atrogene expression levels were significantly lower than in the Dex group. Our results suggest that heat treatment inhibits the development of GC-induced myopathy by decreasing atrogene expression and increasing angiogenesis.

Hyperglycemia inhibits recovery from disuse-induced skeletal muscle atrophy in rats.

The purpose of this study was to evaluate the effects of hyperglycemia on skeletal muscle recovery following disuse-induced muscle atrophy in rats. Wistar rats were grouped as streptozotocin-induced diabetic rats and non-diabetic rats. Both ankle joints of each rat were immobilized to induce atrophy of the gastrocnemius muscles. After two weeks of immobilization and an additional two weeks of recovery, tail blood and gastrocnemius muscles were isolated. Serial cross sections of muscles were stained for myosin ATPase (pH 4.5) and alkaline phosphatase activity. Serum insulin and muscle insulin-like growth factor-1 (IGF-1) levels were also measured. Serum insulin levels were significantly reduced in the diabetic rats compared to the non-diabetic controls. The diameters of type I, IIa, and IIb myofibers and capillary-to-myofiber ratio in the isolated muscle tissue were decreased after immobilization in both treatments. During the recovery period, these parameters were restored in the non-diabetic rats, but not in the diabetic rats. In addition, muscle IGF-1 levels after recovery increased significantly in the non-diabetic rats, but not in the diabetic rats. We conclude that decreased levels of insulin and IGF-1 and impairment of angiogenesis associated with diabetes might be partly responsible for the inhibition of regrowth in diabetic muscle.

Sensory hyperinnervation and increase in NGF, TRPV1 and P2X3 expression in the epidermis following cast immobilization in rats.

BACKGROUND: Cast immobilization is known to induce pain in humans and experimental animal models; however, the detailed mechanisms underlying this pain have yet to be elucidated. Recently, several lines of evidence have indicated that morphological changes in sensory innervation and changes in the expression of pain-related molecules in the epidermis are related to certain painful conditions. The aim of the present study was to temporally investigate the histological changes in the glabrous skin of the rat hind paw after 1, 2 and 4 weeks of ankle joint immobilization by casting. METHODS: The von Frey test and the plantar test were performed to examine noxious sensitivity of the skin. Immunohistochemical methods were used to assess sensory nerve fibre profiles and to examine the expression of the nerve growth factor (NGF), transient receptor potential vanilloid 1 (TRPV1) and P2X3 in the epidermis. RESULTS: Cast immobilization produced a time-dependent increase in mechanical and thermal sensitivity. In the plantar skin of immobilized rats, both myelinated A fibres and unmyelinated C fibres were increased. NGF, TRPV1 and P2X3 expression levels in the epidermis were also increased. Although the level of NGF expression did not display a meaningful change throughout the immobilization period, other changes became remarkable, depending on the period of immobilization. CONCLUSIONS: The time course of the increase in peripheral nerve fibres and in the expression of TRPV1 and P2X3 paralleled the development of hypersensitivity, which suggests that histological changes of the skin following cast immobilization may have some relation to the resulting hypersensitivity.

Hindlimb suspension does not influence mechanical sensitivity, epidermal thickness, and peripheral nerve density in the glabrous skin of the rat hind paw.

Our aim was to investigate the influence of microgravity on the sensitivity of the skin to mechanical stimulation, epidermal thickness, peripheral nerve density in the upper dermis, and serum levels of a stress marker in a rat hindlimb suspension (HS) model. Thirty 8-week-old male Wistar rats were randomly divided into 3 groups: HS, n=10; sham HS, n=10; control, n=10. The suspension system was attached to rat tails in both the HS and sham-HS groups, but the hindlimbs were suspended only in the HS group. The HS and sham-HS groups were treated for 4 weeks. In behavioral tests using von-Frey filaments (n=5 in each group), mechanical hypersensitivity developed in the HS and sham HS groups. Serum corticosterone levels increased significantly in the HS and sham HS groups compared to the control group, and no changes in epidermal thickness or peripheral nerve density were observed immediately after the removal of HS (n=5 in each group). These data indicated that the mechanical hypersensitivity observed in the HS group was not caused by microgravity or inactivity, but rather by restraint stress. We suggest that microgravity does not affect skin sensitivity and histology in these animals. Unit of Physical Therapy and Occupational Therapy Sciences, Nagasaki University Graduate School of Biochemical Sciences, Nagasaki-shi, Japan.

Changes in hind paw epidermal thickness, peripheral nerve distribution and mechanical sensitivity after immobilization in rats.

This study was designed to investigate histological changes in skin tissue accompanying immobilization-induced hypersensitivity. Changes in mechanical sensitivity, epidermal thickness, and peripheral nerve profiles in the upper dermis were examined in glabrous skin of rat hind paw after 1, 2, and 4 weeks of ankle joint immobilization by plaster casts. Induction of mechanical hypersensitivity was confirmed after 2 and 4 weeks of joint immobilization. Epidermal thinning and increase in peripheral nerve profiles were observed in skin tissues in immobilized rats. The time course of epidermal thinning and increase in peripheral nerve profiles were similar closely to that of hypersensitivity, with significant differences between the immobilized and control rats after 2 weeks of immobilization, which became even more remarkable at 4 weeks of immobilization. These findings suggest that joint immobilization by cast induces epidermal thinning and increases peripheral nerve profiles in the upper dermis and that these changes might be partly responsible for immobilization-induced hypersensitivity.

Gadolinium enhancement of cauda equina after combined spinal-epidural anaesthesia.

The occurrence of neurological symptoms after spinal anaesthesia has been reported with several local anaesthetics including lidocaine, prilocaine, mepivacaine, tetracaine and bupivacaine. Although hyperbaric bupivacaine is known to induce neurological symptoms less frequently than lidocaine, a few cases of cauda equina syndrome (CES) following the intraspinal injection of bupivacaine have been reported in the English literature. We describe lumbar MRI findings for a 29-year-old woman presenting with CES after caesarean section.

Thirty cases of bronchial asthma associated with exposure to pet hamsters.

BACKGROUND: The identification, isolation, and elimination of allergen(s) causing bronchial asthma are the most efficient form of treatment. The pet industry has diversified recently, increasing the risk of exposure of pet owners to many unknown antigens. We clinically studied the characteristics of asthma associated with exposure to pet hamsters. METHODS: The study group comprised 30 adults in whom the onset, recurrence, or exacerbation of asthma was triggered by contact with pet hamsters. Clinical characteristics such as sex, age, period required for symptom onset, species of hamster, treatment and disease course, smoking status, and hamster-specific IgE antibodies in serum were studied. RESULTS: The male: female ratio of the study group was 1:1.3, and mean age was 37.7 years. Patients with no previous history of asthma initially presented with cough, progressing to episodes of asthma. Asthmatic symptoms were associated with hamster contact and ranged in severity from mild to severe. Three patients required hospital admission for treatment. The mean period from the start of hamster exposure to the onset of asthmatic episodes was 15.7 months. Dwarf hamsters were responsible for most cases. The CAP-RAST score for hamster-specific IgE antibodies was 1 to 4 in 22 patients and 0 in 8 patients. Eight patients with a score of 1 or higher for hamster-specific IgE antibodies had a CAP-RAST score of 0 for mite antigen. In these patients, terminating hamster contact resulted in a rapid improvement in symptoms, with no need for further treatment. Twenty-three of the 30 subjects (76.7%) were smokers. CONCLUSION: Exposure to pet hamsters is an important risk factor for the onset, recurrence, or exacerbation of asthma. Smoking may also increase the risk of asthmatic symptoms in patients exposed to hamsters.

Clinical evaluation of response to long-term treatment with Pranlukast in patients with bronchial asthma.

BACKGROUND: Short-term treatment with pranlukast, a leukotriene receptor antagonist, has shown to be effective for the management of asthma. The effectiveness and safety of long-term treatment with pranlukast remains to be established. OBJECTIVES: The aim of this study was to determine the effects of pranlukast on morning peak expiratory flow rates (PEFRs), the diurnal variation of these values, and disease severity. METHODS: Fifteen men with bronchial asthma were studied for 5 years. During the first year, the subjects were treated with a bronchodilator; some also received inhaled and oral corticosteroids. During the next 4 years, the subjects received pranlukast in addition. RESULTS: Mean PEFR increased after the start of treatment with pranlukast. The increase in PEFR occurred later in subjects with more severe disease. Diurnal variation of PEFR was unchanged, but subsequently decreased. The condition of all subjects improved, but the greatest improvement was obtained in patients with mild to moderate asthma. CONCLUSIONS: Long-term treatment with pranlukast is effective for the management of bronchial asthma, particularly in patients with mild to moderate disease. Our results suggest that the effectiveness of antiasthmatic drugs should be evaluated over a period of years, rather than on a short-term basis.

Inhibitory effects of D2 agonists by striatal injection on excessive release of dopamine and hyperactivity induced by Bay K 8644 in rats.

We investigated by means of behavioral and neurochemical studies the effects of either D(1) or D(2) agonist on excessive dopamine release and hyperactivity induced by the microinjection of Bay K 8644, and an L-type Ca(2+) channel stimulant, into the rat caudate putamen under a novel environmental condition. Hyperactivity (locomotor activity and rearing counts) and significant increases in extracellular dopamine levels induced by Bay K 8644 were concomitantly observed. D(1) agonist, SKF81297, administered into the caudate putamen did not block Bay K 8644-induced hyperactivity measured by monitoring both animal activity and increases in extracellular dopamine levels detected by microdialysis. Pretreatment with the D(2) agonists, bromocriptine, talipexole and pramipexole, into the caudate putamen significantly blocked Bay K 8644-induced hyperactivity for 45 min after Bay K 8644 administration, although the single administration of these agonists significantly potentiated locomotor activity and rearing behavior. Furthermore, these agonists significantly suppressed Bay K 8644-induced extracellular dopamine levels. Our results indicate that these D(2) agonists (1) act on postsynaptic neuronal D(2) receptors under conditions of normal or low dopamine release in the caudate putamen, and (2) act on presynaptic D(2) receptors (autoreceptors) when excessive levels of dopamine are released or hyperdopamine neuronal activity is induced. Consequently, the effect of D(2) agonists in the clinical treatment of Parkinson's disease may be due to stimulation of postsynaptic D(2) receptors rather than presynaptic autoreceptors.

[Torsion of the middle lobe after right upper lobectomy of the lung; report of a case and the review of the Japanese literatures].

We report a case of torsion of the residual right middle lobe of the lung, following right upper lobectomy for lung cancer. A 71-year-old man who had medical treatment for emphysema was admitted with a lung tumor on chest computed tomography. The tumor was diagnosed as pulmonary adenocarcinoma by transbronchial biopsy. Right upper lobectomy with mediastinal lymph node dissection, and partial resection of the right lower lobe were performed. On the following day, chest X-ray showed an opacification in the right upper lung field, which gradually increased. Bronchoscopic examination revealed a stenotic middle lobe bronchus. Torsion of the middle lobe was suspected, and rethoracotomy was performed on the second postoperative day. The middle lobe was torsed 90-degree counterclockwise around its bronchovascular pedicle. A middle lobectomy was performed secondary to severe congestion. The patient was discharged in good condition on the 11th postoperative day. In reviewing the literatures including this case, 13 of 16 torsions occurred after right upper lobectomy of the lung. Thirteen patients had rethoracotomy, 10 of them underwent resection of the rotated lung. Simple detorsion was carried out in 3 patients, and 1 of them developed cerebral infarction. Lung torsion was reported to be potentially life-threatening. Therefore, fixation of a remaining lobe should be performed. Exploratory thoracotomy should be performed without delay, if lung torsion is suspected.

Influences of a dietary fatty acid composition on the emergence of glutathione S-transferase-P (GST-P) positive foci in the liver of carcinogen-treated rats.

The rats treated with a single i.p. injection of diethylnitrosoamine (DEN) and percial hepatectomy were fed for 11 weeks with a high fat diet mixed with 10% lard, eicosapentaenoic-acid-rich oil (EPA-oil) or arachidonic-acid-rich oil (AA-oil) and the emergence of glutathione S-transferase placental form (GST-P) in the liver was evaluated. There were no significant differences in the serum aminotransferase activities. The molar ratio of n-6 and n-3 fatty acid in the liver phospholipids was significantly low in the EPA-oil group compared with the other groups. In the EPA-oil group, the area percent and the unit area of GST-P positive foci were significantly smaller than the other groups. In the AA-oil group, no significant differences were recognized in the quantitative values for GST-P positive foci compared with the control and lard groups. In conclusion, a hepatic neoplasmic lesion induced by DEN was suppressed with EPA-rich fish oil, and arachidonic-acid-rich oil showed no effect of suppression or acceleration.

[Influential factors in the elevation of serum creatine phosphokinase for the patients with Kanemi Yusho--freeze fracture study of rat muscle plasma membrane].

We studied the factors of the elevation of serum creatine phosphokinase (CK) using the data from the routine medical checkup of Kanemi Yusho patients during 1995 and 1999. We also studied rat muscle plasma membrane by the freeze fracture method, which were given the polychlorinated biphenyls (PCB) and controls. The patients with elevation of serum CK showed significant elevation of PCB in their blood but not in polychlorinated quanterphenyls (PCQ). The rat muscle plasma membrane showed a slight increase of orthognal array density but it was not statistically significant. The densities of caveolae and particles were not changed. Accordingly, PCB were thought to be a factor in the elevation of CK in the serum.