OBJECTIVE: To study the relationship between postmortem interval and the myofibril fragmentation index of skeletal muscle. METHODS: Rabbit skeletal muscle were left in the room temperature for different postmortem intervals, and the protein concentration of each sample was detected by using biuret method. Furthermore, the myofibril fragmentation index of each sample was measured under the protein concentration level of 0.5 mg/mL. RESULTS: The myofibril fragmentation index increased obviously according to the postmortem interval prolongation. CONCLUSION The myofibril fragmentation index may be used on the estimation of early postmortem interval.
Animals ; Calcium-Binding Proteins/metabolism* ; Female ; Male ; Muscle, Skeletal/metabolism* ; Myofibrils/metabolism* ; Postmortem Changes ; Proteins/metabolism* ; Rabbits ; Spectrophotometry ; Time Factors

In order to elucidate muscle functional changes by acute reloading, contractile and fatigue properties of the rat soleus muscle were investigated at three weeks of hindlimb suspension and the following 1 hr, 5 hr, 1 d, and 2 weeks of reloading. Compared to age-matched controls, three weeks of unloading caused significant changes in myofibrillar alignments, muscle mass relative to body mass (-43%), normalized tension (-35%), shortening velocity (+143%), and response times. Further significant changes were not observed during early reloading, because the transitional reverse process was gradual rather than abrupt. Although most of the muscle properties returned to the control level after two weeks of reloading, full recovery of the tissue would require more than the two-week period. Delayed recovery due to factors such as myofibrillar arrangement and fatigue resistance was apparent, which should be considered for rehabilitation after a long-term spaceflight or bed-rest.
Animals ; Hindlimb Suspension ; Lactic Acid/metabolism ; Microscopy, Electron ; Muscle Contraction/*physiology ; Muscle Fatigue/*physiology ; Muscle, Skeletal/cytology/*physiology ; Myofibrils/ultrastructure ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Weight-Bearing/physiology

PURPOSE: The purpose of this study was to examine the effects of cerebral ischemia on Type I(soleus) and Type II(plantaris, gastrocnemius) muscles, and to determine the effects of isometric contraction training by electrostimulation on Type I andII muscles in cerebral ischemia model rats. METHOD: Twenty-five male Sprague-Dawley rats were randomly divided into four groups: ST(stroke), STES(stroke+electrostimulation), SH(sham) and SHES (sham+electrostimulation). The ST and STES groups received a transient right middle cerebral artery occlusion operation. The SH and SHES groups received a sham operation. The STES and SHES groups had daily isometric contraction training by electrostimulation(100Hz, 45mA, 7.5V) on hindlimb muscles for 7days. RESULT: Plantaris and gastrocenmius muscle weight, myofibrillar protein contents of soleus and gastrocnemius, and the muscle fiber cross-sectional area of gastrocnemius in the ST group significantly decreased compared with the SH group. Soleus, plantaris, gastrocnemius muscle weight, myofibrillar protein contents of soleus and gastrocnemius, and the Type I muscle fiber cross-sectional area of soleus and the Type II muscle fiber cross-sectional area of gastrocnemius in the STES group significantly increased compared with the ST group. CONCLUSION: Hindlimb muscle atrophy occurs after acute stroke and isometric contraction training by electrostimulation during early stages of a stroke attenuates muscle atrophy of Type I and Type II muscles.
Animals ; Body Weight ; Brain Ischemia/*complications ; Disease Models, Animal ; Electric Stimulation ; Hindlimb ; *Isometric Contraction ; Male ; Muscle Proteins/analysis ; Muscle, Skeletal/metabolism/pathology/*physiopathology ; Muscular Atrophy/*etiology/pathology/physiopathology ; Myofibrils/chemistry ; Rats ; Rats, Sprague-Dawley ; Stroke/*complications

OBJECTIVETo investigate effects of Shenfu injection on the concentrations of plasma tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), activity of Nuclear Factor kappa B (NF-kappaB) and heart tissue ultrastructure during myocardial ischemia/reperfusion (I/R) injury in rats and its potential mechanism.

METHODSMyocardial ischemia/reperfusion (I/R) was produced by ligation and release of the left anterior descending coronary artery. Ischemia lasted for 30 min and reperfusion for 60 min. Twenty-four healthy male SD rats weighing 230-280 g were randomly divided into three groups (n = 8, each): Group I (Sham-operation group); Group II (I/R group); Group III (Shenfu group), in which Shenfu injection (10 ml/kg) was intraperitoneally injected 30 min before ischemia in animals with I/R. The plasma concentrations of IL-6 and TNF-alpha were measured by ELISA, and the heart was harvested for determination of NF-kappaB levels by Ecl-western blot analysis. Electron microscopy was used to study its ultrastructure.

RESULTSAfter reperfusion, NF-kappaB binding activity in myocardial nuclei and the plasma concentrations of IL-6 and TNF-alpha were significantly increased in Group II, compared with Group I (P < 0.01), and they were markedly reduced in Group III, compared with Group II (P < 0.01). In addition, electron microscopic examination showed more serious injury of the myocardium ultrastructure in Group II, while in Group III the myocardial ultrastructure was similar to normal state.

CONCLUSIONSShenfu injection inhibits NF-kappaB activity in I/R myocardium and leads to down-regulation of proinflammatory cytokine expression, which might be one of the molecular mechanisms of Shenfu injection in cardioprotection.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Interleukin-6 ; blood ; Male ; Myocardial Reperfusion Injury ; drug therapy ; metabolism ; pathology ; Myofibrils ; ultrastructure ; NF-kappa B ; antagonists & inhibitors ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha ; analysis