OBJECTIVETo observe the effects of polyethylene oxide (PEO) on microcirculation of normal rat hindlimb skeletal muscle.

METHODSSixteen male Wistar rats were anesthetized and equally and randomly divided into PEO group (administered with 10 ppm PEO solution) and control group (administered with equal volume of normal saline). The PEO solution or saline was separately injected through the caudal vein at a constant rate of 5 ml/h for 20 minutes. Using short axis view at right mid thigh region, contrast-enhanced ultrasonography was performed before and after the administration of solution. Electrocardiogram, blood pressure, and central venous pressure were also monitored.

RESULTSIn the PEO group, after the administration of PEO, microcirculation capillary volume increased from (20.78±2.63) dB to (22.40±1.94) dB (P=0.023), red blood cell velocity from (0.27±0.08) s-1 to (0.35±0.13) s-1(P=0.010), and capillary blood flow from (5.65±1.81) dB/s to (7.91±3.28) dB/s (P=0.013). In the control group, there were no significant changes in microcirculation capillary volume, red blood cell velocity, and capillary blood flow (all Pþ0.05) after the injection of normal saline. The changes of heart rates, blood pressures and central venous pressure were not significant after the administration of either PEO or saline (all Pþ0.05).

CONCLUSIONPEO can remarkably increase capillary volume, red blood cell velocity, and capillary blood flow in normal rat hindlimb skeletal muscle.

Animals ; Hindlimb ; blood supply ; Male ; Microcirculation ; drug effects ; Muscle, Skeletal ; blood supply ; Polyethylene Glycols ; pharmacology ; Rats ; Rats, Wistar

The present study aimed to observe the changes of contractile function and responsiveness to isoproterenol (ISO) in tail-suspended rat cardiomyocytes under simulated weightlessness condition. Tail-suspended rat model was used to simulate weightlessness on the ground. Twenty-four male Sprague-Dawley rats were randomly divided into the control and tail-suspended groups. After 4 weeks of suspension, the rats were injected with heparin (100 IU/100 g body weight, i.p.) and anesthetized with pentobarbital sodium (40 mg/kg body weight). The hearts were removed and the aortas were cannulated rapidly. The cannulated hearts were mounted on a Langendorff perfusion apparatus and perfused with constant flow. The perfusion pressure was monitored. The hearts were digested by 0.08% collagenase I at 37 degrees C. The ventricular tissues were chopped and the single myocytes were dispersed gently by a wide-tipped pipette. The contractile function was measured in the Edge Detector system within 6 h after isolation. The length and width of cardiomyocytes were measured without electric stimulation. Contractile curves of the single cardiomyocytes were recorded at stimulation frequency of 1.0, 2.0 and 4.0 Hz. To observe the responsiveness of cardiomyocytes to ISO, 1, 5 and 10 nmol/L ISO in Kreb's solution was perfused at a stimulation frequency of 2.0 Hz. The length and width of the left and right ventricular cardiomyocytes in tail-suspended group had little difference from that in the control group. The unloaded shortening amplitude increased as stimulation frequency elevated in both the control and tail-suspended groups. It was increased by (8.50±1.26)%, (9.00±1.38)%, (9.23±1.83)% in the left ventricular cardiomyocytes, and (9.80±2.48)%, (10.03±2.48)%, (10.28±2.27)% in the right ventricular cardiomyocytes in the control group at stimulation frequency of 1.0, 2.0 and 4.0 Hz. Compared with that in the control group, the unloaded shortening amplitude decreased by 12.2% and 10.9% in the left ventricular cardiomycytes (P<0.05), and 16.5% and 16.3% in the right ventricular cardiomyocytes (P<0.05) at stimulation frequency of 1.0 and 2.0 Hz in tail-suspended group. There was no significant difference in unloaded shortening amplitude at stimulation frequency of 4.0 Hz between the control and tail-suspended groups. Time to peak shortening (TPS) in tail-suspended group significantly reduced in both the left and right ventricular cardiomyocytes (P<0.05). Time from peak to 75% relaxation (TR(75)) in tail-suspended group significantly prolonged in both the left and right ventricular cardiomyocytes (P<0.05). No significant differences in shortening and relaxation rate (±dL/dt(max)) were observed between the control and tail-suspended groups. The unloaded shortening amplitude increased by (10.63±0.83)%, (35.06±5.22)% and (71.64±6.83)% in the control cardiomyocytes, but increased by (5.75±0.76)%, (23.97±4.50)% and (26.38±8.13)% in tail-suspended group during perfusion with 1, 5 and 10 nmol/L ISO (P<0.05, P<0.01). The unloaded shortening amplitude increased by (3.04±0.27)%, (9.81±2.66)% and (20.20±3.47)% in the control cardiomyocytes, but increased by (1.42±0.53)%, (3.83±1.71)% and (5.49±4.08)% in tail-suspended group during perfusion with 10, 50 and 100 nmol/L forskolin (P<0.05). The results obtained suggest that the unloaded shortening amplitude and responsiveness to ISO decrease in rat cardiomyocytes after 4-week tail-suspension.
Animals ; Electric Stimulation ; Hindlimb Suspension ; Isoproterenol ; pharmacology ; Male ; Myocytes, Cardiac ; drug effects ; Rats ; Rats, Sprague-Dawley ; Weightlessness Simulation

The formalin test is a model of injury-produced inflammatory pain. Anesthetics, in clinically relevant concentrations, affect neutrophils and immune suppression. This study was to determine whether halothane reliably inhibits inflammatory reaction and formalin induced pain behavior or does not. Rats were exposed to 100% oxygen (control) or halothane, respectively for 30 min and then 24 hr later five percent formalin test was assessed. The base values of the paw's diameter were obtained earlier, and then formalin induced edema was assessed by measuring diameters of the injected paws at 5 min, 1 hr, 4 hr and 24 hr after the injection. Nociceptive behavior was quantified by counting the number of times with the paw flinched at 5 min intervals for 60 min. The diameters of edema in the halothane group lessened more than those in the oxygen group at 1 and 24 hr in each following of the injection (p<0.05). The rats pre-administered with oxygen or halothane were similar appearances in nociceptive behaviors. It suggests that halothane anesthesia might inhibit slightly the inflammatory reaction with the formalin-induced edema but might not inhibit the formalin-induced pain behavior in the event of pre-administration halothane 24 hr earlier before the formalin test of rat.
Anesthetics, Inhalation/pharmacology ; Anesthetics, Inhalation/immunology* ; Animal ; Edema/immunology* ; Edema/chemically induced ; Formaldehyde/pharmacology ; Formaldehyde/immunology ; Halothane/pharmacology ; Halothane/immunology* ; Hindlimb/immunology ; Hindlimb/drug effects ; Male ; Rats ; Rats, Sprague-Dawley

BACKGROUNDXiaobuxin-Tang, a traditional Chinese herbal prescription recorded in a silk scroll unearthed from Mogao Caves of Dunhuang has been indicated that it can remit depressive disorder. The present study was designed to investigate its antidepressant effects in various animal depression models.

METHODSXiaobuxin-Tang was extracted by 70% alcohol, and then three behavioral despair models and 5-Hydroxytryptophan (HTP)-induced head twitch response model were adopted to assess the antidepressant effects of the ethanolic extract of Xiaobuxin-Tang with the study on spontaneous motor activity. Groups of mice and rats received oral treatment with Xiaobuxin-Tang (150 - 1200 mg/kg) only once acutely in all tests. The duration of immobility was measured during the last 4 minutes of the 6-minutes test period in mice forced swimming test, rats forced swimming test and mice tail suspension test. In 5-HTP-induced head twitch response, the mice were intraperitoneally administered with 120 mg/kg of L-5-HTP, and then the cumulative number of head twitches was counted in 20 minutes. Spontaneous motor activities of mice were recorded automatically in 10 minutes by VIDEOMEX-V image analytic system.

RESULTSThe extract at doses of 300 mg/kg (p.o.) and 600 mg/kg (p.o.) significantly decreased the duration of immobility time in a dose dependent manner in mice forced swimming test; also, the extract at dose of 1200 mg/kg (p.o.) significantly decreased the duration of immobility time in rat forced swimming test. Furthermore, the extract at a dose of 600 mg/kg had the same effect in mice tail suspension test. Meanwhile, the extract at the effective doses for behavioral despair models, had no effect on spontaneous motor activity in mice. The extract (300 - 1200 mg/kg, p.o.) also increased the accumulative number of the 5-HTP-induced head twitch response in mice in 20 minutes.

CONCLUSIONOur results suggested that the ethanolic extract of Xiaobuxin-Tang exerts antidepressant-like effect.

Animals ; Antidepressive Agents ; pharmacology ; Depression ; drug therapy ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Hindlimb Suspension ; Male ; Mice ; Mice, Inbred ICR ; Motor Activity ; drug effects ; Swimming

OBJECTIVETo study the role of cAMP in repair of hemisection of spinal cord in rats models.

METHODSRats models of spinal cord hemisection were made and cAMP were injected once in the motor cortex or continuously input in the lesion area or in the subarachnoid cistern for 3 d. NFs, GFAP, CSTs and spinal axons in the lesion areas were observed by immunohistochemistry and hind limb movements were evaluated in BBB scales.

RESULTSMany regenerated axons were presented in the lesion areas in cAMP groups though no continuous long regenerated axons traversed the lesion area when cAMP was input in the motor cortex or in the local lesion area. In control group, no regenerated axon were presented in the lesion areas. When cAMP was input in the subarachnoid cistern, only few-labelled CST axon survived and presented in the lesion area comparing no labelled CST axon presented in the lesion area. More NFs and less GFAP were distributed and extended in the lesion area in the cAMP groups. All the rats restored to normally walk 4-5 weeks after operations and no significance existed between cAMP groups and control groups comparing the BBB scales of hind limb movements.

CONCLUSIONcAMP injected in the brain cortex or continuously input in the lesion area can induce the axonal regeneration.

Administration, Topical ; Animals ; Cyclic AMP ; administration & dosage ; physiology ; Hindlimb ; physiopathology ; Male ; Nerve Regeneration ; drug effects ; Rats ; Rats, Sprague-Dawley ; Spinal Cord Injuries ; drug therapy ; physiopathology

PURPOSE: The purpose of this study was to examine the effect of DHEA (Dehydroepiandrosterone) on muscle weight and Type I and II fiber cross-sectional area of affected and unaffected hindlimb muscles in rats with neuropathic pain induced by unilateral peripheral nerve injury. METHODS: Neuropathic pain was induced by ligation and cutting of the left L5 spinal nerve. Adult male Sprague-Dawley rats were randomly assigned to one of two groups: The DHEA group (n=10) had DHEA injections daily for 14 days, and the Vehicle group (n=10) had vehicle injections daily for 14 days. Withdrawal threshold, body weight, food intake and activity were measured every day. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected from the both hindlimbs. Body weight, food intake, activity, muscle weight and Type I, II fiber cross-sectional area of the dissected muscles were measured. RESULTS: The DHEA group showed significant increases (p<.05), as compared to the vehicle group for muscle weight of the unaffected plantaris, and in Type II fiber cross-sectional area of the gastrocnemius muscle. The DHEA group demonstrated a higher pain threshold than the vehicle group whereas total diet intake and activity score were not significantly different between the two groups. CONCLUSION: DHEA administration for 14 days attenuates unaffected plantaris and gastrocnemius muscle atrophy.
Animals ; Body Weight ; Dehydroepiandrosterone/*administration & dosage ; Disease Models, Animal ; Eating/drug effects ; *Hindlimb ; Male ; Muscle Fibers, Skeletal/*drug effects/pathology ; Muscle, Skeletal/drug effects ; Muscular Atrophy/*drug therapy ; Pain/etiology ; Pain Measurement ; Peripheral Nerves/*injuries ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo compare the effects of Wujia Bugu decoction and Alendronate sodium on protecting bone and muscle loss of hindlimb unloaded rats lasting three weeks.

METHODSMarch to May, 2009, 40 male Wistar rats with age of 6-week, were randomized divided to four groups (10 rats in each group): hindlimb unloaded group treated with Chinese medicine (HUC), hindlimb unloaded group treated with alendronate sodium (HUA), control group (CON), as well as hindlimb unloaded group (HU). During the experiment, rats of HUC was given Wujia Bugu decoction (including the Ciwujia, Shudihuang, Huainiuxi, Muli, etc. with the concentration of 0.704 g/ml) 10 ml/kg weight once a day, HUA was given quantitative alendronate sodium slice dissolve suspension (0.9 mg/ml) once a week. CON and HU were given double-distilled water. The experiment lasted 4 weeks,from the second to the forth week, rats in HU, HUC, HUA were hindlimb unloaded. All rats were sacrificed at the fourth weekend, the content of Ca, P and the activation of ALP in serum, Bone mineral density (BMD) of humerus and femurs, Biomechanical property of tibia and humerus, as well as the weight index of biceps and sural muscles were measured.

RESULTSCompared with CON, serum Ca of HU was significantly increased (P < 0.05), BMD, mechanical properties, muscle index of hindlimb were significantly reduce (P < 0.01), the serum Ca of HUA significantly increased (P < 0.05). Serum ALP of HUC was significantly higher than other three groups (P < 0.01). Compared with HU, femoral BMD of HUC and HUA significantly increased, tibial maximum load, maximum deflection and elastic load had increased tendency; calf muscle atrophy of HUC and HUA was alleviate 50% and 12.5% respectively (P > 0.05), humeral BMD had no significant difference, while the maximum deflection (P < 0.01) and elastic deflection (P < 0.05) in humerus of HUA were significantly lower.

CONCLUSIONHerbal prescription and alendronate sodium can effectively protect the bone and muscle loss of hindlimb unloaded rats, improve its mechanical structure. Herbal prescription has advantages of relieving mechanical properties change. The effects of Wujia Bugu decoction and alendronate sodium are similar in treating space weightlessness bone loss.

Alendronate ; administration & dosage ; Animals ; Bone Density ; drug effects ; Bone Resorption ; drug therapy ; physiopathology ; Disease Models, Animal ; Drugs, Chinese Herbal ; administration & dosage ; Femur ; drug effects ; physiopathology ; Hindlimb Suspension ; Humans ; Humerus ; drug effects ; physiopathology ; Male ; Random Allocation ; Rats ; Rats, Wistar

PURPOSE: The purpose of this study was to determine the effect of DHEA on hindlimb muscles(soleus, plantaris and gastrocnemius) in a focal brain ischemia model rat. METHOD: Twenty-seven male Sprague-Dawley rats were randomly divided into three groups: CINS(cerebral ischemia + normal saline), CIDH(cerebral ischemia + DHEA), or SHNS(sham + normal saline). Both the CINS and CIDH groups underwent a transient right middle cerebral artery occlusion operation. In the SHNS group, a sham operation was done. 0.34mmol/kg DHEA was administered daily by an intraperitoneal injection for 7days. RESULT: The muscle weight, muscle fiber cross-sectional area of the Type I muscle fiber of soleus and Type II muscle fiber of plantaris and gastrocnemius, myofibrillar protein content of gastrocnemius, and muscle strength in the CINS group decreased compared with the SHNS group. The muscle weight, muscle fiber cross-sectional area of the Type II muscle fiber of plantaris and gastrocnemius, myofibrillar protein content of soleus, and muscle strength in the CIDH group increased compared with the CINS group. CONCLUSION: It was identified that muscle atrophy could be induced during 7 days after a cerebral infarction, and DHEA administration during the early stages of a cerebral infarction might attenuate muscle atrophy.
Animals ; Brain Ischemia/*pathology ; Dehydroepiandrosterone/*pharmacology ; Hindlimb ; Male ; Muscle, Skeletal/*drug effects/pathology ; Muscular Atrophy/chemically induced ; Rats ; Rats, Sprague-Dawley

UNLABELLEDTo study the effect of a Chinese herbal prescription on external calcium deposition to weight-bearing bone in simulated weightlessness rats.

METHODTwenty-one male Wistar rats were divided into 3 groups: control group, tail suspension group, tail suspension with Chinese medicine group which takes a Chinese herbal prescription extract (containing Radix Rehmanniae Preparata, Radix Acanthopanacis Bidentatae, Radix Astragali, Radix Angelicae Sinensis, Concha Ostreae prepared by acetic acid) by intragastric administration. After 1 week adaption, there start off 3 weeks simulated weightlessness by tail suspension. At the eleventh day of simulated weightlessness, every rat was given one equal dose of 41Ca tracer by intragastric administration. Right femurs were separated as experiment over, and the ratio of 41Ca to 40Ca (41Ca/40Ca) was measured by accelerator mass spectrometry (AMS), while total femur calcium was measured by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Femur 41Ca deposition amount (DA) and femur 41Ca deposition ratio (DR) were calculated.

RESULTThe results showed that compared with control group, 41Ca/40Ca decreased significantly (P < 0.001) in tail suspension group, while in tail suspension with Chinese medicine group, it significantly increased (P < 0.05). DA and DR were both decreased significantly (P < 0.001) in tail suspension group, but no significant change in tail suspension with Chinese medicine group as compared with control group. Compared with tail suspension group, DA and DR increased significantly (P < 0.001) in tail suspension with Chinese medicine group.

CONCLUSIONSimulated weightlessness by tail suspension can cause decreased deposition of external calcium to weight-bearing bone, and the Chinese herbal prescription in this trial is effective to prevent the decrease. Moreover, multiple mechanisms may contribute to weightlessness induced osteoporosis, besides calcium deposition disturbance.

Animals ; Bone Resorption ; etiology ; metabolism ; Calcification, Physiologic ; drug effects ; Calcium ; metabolism ; Calcium Radioisotopes ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Femur ; drug effects ; metabolism ; Hindlimb Suspension ; Male ; Mass Spectrometry ; Rats ; Rats, Wistar ; Weightlessness Simulation ; adverse effects

PURPOSE: The purpose of this study was to determine the effect of Dehydroepiandrosterone (DHEA) administration alone or exercise combined with DHEA before steroid treatment on rat hindlimb muscles. METHODS: Male Sprague-Dawley rats were assigned to one of three groups: a steroid group (S, n=10) that had no treatment for 7 days before steroid treatment; a DHEA-steroid group (DS, n=8) that had 0.34 mmol/kg/day DHEA injection once a day for 7 days before steroid treatment and an exercise?steroid group (EDS, n=9) that ran on the treadmill combined with 0.34 mmol/kg/day DHEA injection for 7 days before steroid treatment. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected. Body weight, food intake, muscle weight, myofibillar protein content and cross-sectional area of the dissected muscles were determined. RESULTS: The DS group showed significant increases (p<.05) as compared to the steroid group in body weight, and muscle weight of gastrocnemius muscles. The EDS group showed significant increases (p<.05) as compared to the S group in body weight, muscle weight, myofibrillar protein content, and Type II fiber cross-sectional area of soleus, plantaris and gastrocnemius muscles. CONCLUSION: Exercise combined with DHEA administration before steroid treatment prevents steroid induced muscle atrophy, with exercise combined with DHEA administration being more effective than DHEA administration alone in preventing muscle atrophy.
Animals ; Body Weight ; Dehydroepiandrosterone/*administration & dosage ; Hindlimb ; Male ; Muscle Contraction/drug effects ; Muscle, Skeletal/*drug effects/pathology ; Muscular Atrophy/chemically induced/*prevention & control ; *Physical Conditioning, Animal ; Rats ; Rats, Sprague-Dawley ; Steroids/*toxicity