1.Weightlessness-simulated Experimental Apparatus: Hindlimb Unloading Model in Rat-Technical Aspects.
Sang Ho HWANG ; Chan Kwon JUNG
Korean Journal of Aerospace and Environmental Medicine 2005;15(2):52-55
No abstract available.
Animals
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Hindlimb Suspension*
;
Hindlimb*
2.A Histochemical Changes of Calf Muscle Fibers after Rat Hindlimb Suspension.
Han Young JUNG ; Jun Ki LEE ; Yoon Koo KANG
Journal of the Korean Academy of Rehabilitation Medicine 1997;21(1):186-193
purpose of this study was to investigate alterations in histochemical properties in the gastrocnemius & soleus muscles of rats following hindlimb suspension for 1 week. A modification of the Morey and Musacchia models was used to determine atrophic responses of rat muscle. The weights of rat's whole body and of gastrocnemius and soleus muscles were affected by suspensions. A reduction of type I distribution was accompanied by an increase in type II fibers. The cross sectional area of all fiber types was reduced after suspension. These results suggest that type I fibers showed greater susceptibility than type II fibers and some amount of type I fibers might have been converted to type II fibers.
Animals
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Hindlimb Suspension*
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Hindlimb*
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Muscles
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Rats*
;
Suspensions
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Weights and Measures
3.Implementation of a Two-dimensional Behavior Matrix to Distinguish Individuals with Differential Depression States in a Rodent Model of Depression.
Jin Young PARK ; Tae Kyung KIM ; Juli CHOI ; Jung Eun LEE ; Hannah KIM ; Eun Hwa LEE ; Pyung Lim HAN
Experimental Neurobiology 2014;23(3):215-223
Animal models of depression are used to study pathophysiology of depression and to advance therapeutic strategies. Stress-induced depression models in rodents are widely used. However, amenable behavioral criteria and experimental procedures that are suitable for animal models have not been established. Given that depression is clinically diagnosed by multiple symptomatic criteria and stress effects are imposed to the brain non-specifically in stress-induced depression models, analyses of depression states in rodents using multiple symptomatic criteria may provide more power than any methods relying on a single symptomatic criterion. To address this, C57BL/6 inbred mice were restrained for 2 h daily for 14 d, and depression states of individual mice were assessed using the U-field test, behavioral assessment developed to measure animal's sociability, and the tail suspension test and/or forced swim test, which are the typical methods that measure psychomotor withdrawal states. Although the majority of these mice showed severe depressive behaviors in both tests, a significant proportion of them, which were all inbred mice and received the same amount of restraints, expressed differential depression states in the sociability test and psychomotor withdrawal tests. To easily read-out differential depression states of individuals in two different tests, a standard method and basic parameters required to construct two-way behavior matrix were introduced. The utility and features of this two-way behavior analysis method for studies of different depressive states of individuals were discussed.
Animals
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Brain
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Depression*
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Hindlimb Suspension
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Mice
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Models, Animal
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Rodentia*
4.Changes in muscle spindle afferent discharge activities in rat soleus following hindlimb immobilization.
Xuehong ZHAO ; Wenjing ZHANG ; Xi ZHOU ; Yan GAO ; Xiaoli FAN ; Guangbin LIU
Journal of Southern Medical University 2015;35(2):252-255
OBJECTIVETo investigate the changes in the afferent discharge activities of the sensory nerve endings in muscle spindles of rats with hindlimb immobilization.
METHODSPlaster cast was used immobilize the hindllimbs of rats. Using air-gap technique, the spontaneous discharge of the muscle spindles and its responses to perfusion with succinylcholine (0.05 mg/ml) and suspension in an extended position were observed in isolated muscle spindles from rats with hindlimb immobilization for 3, 7, and 14 days.
RESULTSThe muscle spindles of rat soleus showed a sharp decrease in spontaneous discharge frequency (P<0.01) and response to succinylcholine perfusion after 3 days of hindlimb immobilization (P<0.05). Significant changes of the firing rate in an extended position was observed in rats after a 14-day immobilization (P<0.01). The duration of individual spikes was significantly prolonged following hindlimb immobilization (P<0.01).
CONCLUSIONMuscle spindle discharges decrease significantly in rats following hindlimb immobilization, which might be related to reduced contractile properties of the muscle spindle.
Animals ; Hindlimb Suspension ; Muscle Spindles ; innervation ; Muscle, Skeletal ; innervation ; Rats
5.Effects of hindlimb immobilization on the carbohydrate metabolism and insulin receptor of the skeletal muscle in rats.
Dong Chul LEE ; Jae Man RYOO ; Joo Chul IHN ; Jong Yeon KIM ; Suck Kang LEE
The Journal of the Korean Orthopaedic Association 1992;27(4):1178-1186
No abstract available.
Animals
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Carbohydrate Metabolism*
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Hindlimb Suspension*
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Hindlimb*
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Insulin*
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Muscle, Skeletal*
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Rats*
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Receptor, Insulin*
6.Morphological changes in rat testes after Hindlimb Unloading model.
Hae Chul AHN ; Chul Hyun KIM ; Jae Hyeng IM ; Gi ho LEE ; Sahng LEE ; Mi Ja PARK ; Chan KIM
Korean Journal of Aerospace and Environmental Medicine 2006;16(3):49-56
BACKGROUND: The purpose of this study was to examine histological changes of testes induced by hindlimb unloading & position change of testis in mature adult male rats. METHOD: Eight month old (390~410g) 36 male Sprague-Dawley rats were weight-matched assigned to Ground Control (GC), Hindlimb Unloading (HU), Hindlimb Unloading & Testis Tie(HUT), Intra-abdominal Testis(IAT) for 24 days. Daily body weight was watched for status of animal. Testis weight, Seminiferous Tubule Diameter(STD), Seminiferous Tubule Perimeter(STP), Serminiferous Tubule Area(STA), Sertori Cell Height(SCH) were examined in each group. RESULTS: The 24-day hindlimb unloading of HU, HUT and IAT showed no significant change of body weight compared to GC. HUT maintained the weights, STD, STP, STA, SCH of their testes as GC while HU, IAT had significantly decreased the weights, STD, STP, STA of their testes. CONCLUSION: These results support that hindlimb unloading experiment induces serious morphological changes of testes. Therefore, on the hindlimb unloading experiment, IAT should be avoid or the effect of IAT should be correct. It will be necessary to study the pure effect of hindlimb unloading without IAT on the musculoskeltal system and so on which are associated with testosterone.
Adult
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Animals
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Body Weight
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Hindlimb Suspension*
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Hindlimb*
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Humans
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Male
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Rats*
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Rats, Sprague-Dawley
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Seminiferous Tubules
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Testis*
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Testosterone
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Weightlessness
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Weights and Measures
7.Relationship between simulated weightlessness-induced muscle spindle change and muscle atrophy.
Acta Physiologica Sinica 2013;65(1):96-100
One of the most important and urgent issues in the field of space medicine is to reveal the potential mechanism underlying the disused muscle atrophy during the weightlessness or microgravity environment. It will conduce to find out effective methods for the prevention and treatment of muscle atrophy during a long-term space flight. Increasing data show that muscle spindle discharges are significantly altered following the hindlimb unloading, suggesting a vital role in the progress of muscle atrophy. In the last decades, we have made a series of studies on changes in the morphological structure and function of muscle spindle following simulated weightlessness. This review will discuss our main results and related researches for understanding of muscle spindle activities during microgravity environment, which may provide a theoretic basis for effective prevention and treatment of muscle atrophy induced by weightlessness.
Animals
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Hindlimb Suspension
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Muscle Spindles
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physiopathology
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Muscle, Skeletal
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physiopathology
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Muscular Atrophy
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physiopathology
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Space Flight
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Weightlessness Simulation
8.Anti-depression effect of Kai Xin San and research of its compatibility.
Yi-hong CHEN ; Dong-xiao WANG ; Ping LIU ; Jin-liang WANG ; Chang DAI ; Gui-fang CHENG
Chinese Medical Journal 2005;118(14):1214-1216
9.Spectral analysis of blood pressure signal in conscious rats released from simulated microgravity.
Jiu-Hua CHENG ; Shou-Yan WANG ; Li-Fan ZHANG ; Xin LIU ; Yang LIU ; Jin MA
Acta Physiologica Sinica 2008;60(1):74-82
The aim of the present study was to examine whether there are changes in systolic and diastolic blood pressure (SBP and DBP) and heart rate (HR) and their spectral indices in conscious free-moving rats after tail-suspension for 28 d. The tail-suspended hindlimb-unloaded (HU) rat model was used to simulate the cardiovascular effect of microgravity and the post-spaceflight cardiovascular dysfunction. The auto- and cross-spectral analysis of SBP variability (SBPV) and HR variability (HRV) were performed by the method based on the autoregressive model (AR), and the auto-spectral results was compared with the results from the classical periodogram method. The baroreceptor-heart rate reflex sensitivity (BRS) was estimated using transfer function analysis from SBP to HR. The results indicated that auto-spectral results based on the two methods were comparable, while smoother power spectral curves with distinguished peaks were trained by the AR method. The means of SBP, DBP, and HR, the main spectral indices of SBPV and HRV, and the mean average gain of transfer functions computed at low- and high-frequency ranges (0.25-0.8 Hz and 0.8-2.4 Hz) did not show significant changes before and after release from suspension. Furthermore, the main spectral indices of SBPV and HRV at different time points did not show significant differences between the control and suspension groups. However, the means of SBP, DBP, and HR at different time points were significantly higher in simulated weightless rats than those in the control rats. The findings of the present study suggest that a mid-term simulated microgravity might induce hypertension and tachycardia upon removal from the suspension which reflects a general sympathetic hyperactivity. We speculated that the sympathetic hyperactivity might be a compensatory mechanism activated in the intact animal to counteract HU-induced hypo-responsiveness of resistance vessels. In addition, lack of clear and distinct changes in HRV and BRS have also been reported in some recent space and ground-based human studies.
Animals
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Baroreflex
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Blood Pressure
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Heart Rate
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Hindlimb Suspension
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Hypertension
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Rats
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Weightlessness Simulation
10.A brief review of bone adaptation to unloading.
Ping ZHANG ; Kazunori HAMAMURA ; Hiroki YOKOTA
Genomics, Proteomics & Bioinformatics 2008;6(1):4-7
Weight-bearing bone is constantly adapting its structure and function to mechanical environments. Loading through routine exercises stimulates bone formation and prevents bone loss, but unloading through bed rest and cast immobilization as well as exposure to weightlessness during spaceflight reduces its mass and strength. In order to elucidate the mechanism underlying unloading-driven bone adaptation, ground-based in vitro and in vivo analyses have been conducted using rotating cell culturing and hindlimb suspension. Focusing on gene expression studies in osteoblasts and hindlimb suspension studies, this minireview introduces our recent understanding on bone homeostasis under weightlessness in space. Most of the existing data indicate that unloading has the opposite effects to loading through common signaling pathways. However, a question remains as to whether any pathway unique to unloading (and not to loading) may exist.
Adaptation, Physiological
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Animals
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Bone and Bones
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cytology
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physiology
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Hindlimb Suspension
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physiology
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Humans
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Osteoblasts
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physiology
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Weightlessness