ABSTRACT
[Objective]To investigate the effect of human umbilical cord mesenchymal stem cells on infected state of human alve?olar type Ⅱ epithelial cells.[Methods]Human alveolar type Ⅱ epithelial cells A549(1×105/mL)2 mL and PA(3×104 CFU/mL)2 mL has grown after 6 hours,add hUCMSC(1 × 106/mL)2 mL as the experimental group,add equal amounts of phosphate buffer (PBS)for infection,A549 and PBS and the medium has grown as the control group. A549 cells morphological changes between the compared groups(Transmission electron microscope,TEM),A549 cell viability(new CCK-8 cell proliferation assay Kit),A549 cells apoptosis(Annexin V-FITC/PI double staining flow cytometry)and the expression of A549 pulmonary surfactant A(SP-A) (Western blot).[Results]Transmission electron microscope cell morphology observation displayed ,infection group A549 cell dam?aged obviously,cell quality appeared empty bubble degeneration,chromatin height agglutination,visible apoptosis bodies;experi?ment group cell package film structure full,nuclear film full,nucleolus obviously,nuclear chromatin electronic density low,chroma? tin uniform,no apoptotic bodies;control group A549 cell structure full,membrane surface micro-fluff rich,nuclear film full,nucle?ar week clearance structure normal,chromatin uniform;infection group and control group compared,Infection group A549 cell sur?vival significantly reduced[(70.35±2.89)% and(97.37±2.07)%,n=3,P<0.01],apoptosis rate significantly increased[(8.63%± 0.16)%and(2.55±0.11)%,n=3,P<0.01],In the infected group,PA could damage A549 cells and decrease the amount of SP-A ex?pression(n=5,P<0.05). In the experiment group,the protective effect of hUCMSC on the A549 cells after infection may increase the expression of SP-A(n=5,P<0.05);[Conclusions]HUCMSC inhibits the infection of A549 cells apoptosis and protection of A549 cells secrete SP-A.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the relationship between contractile characteristics and fiber type conversion in hind-limb unloading mice soleus.</p><p><b>METHODS</b>After 28-day hind-limb unloading and muscle atrophy, we used the method of isolated muscle perfusion with different stimulated protocols to determine the changes in contractile characteristics including the isometric twitch force and tetanus force and fatigue index of slow twitch muscle in mice. The muscle myofibrillar composition and fiber type conversion were detected by immunofluorescence staining and real-time PCR.</p><p><b>RESULTS</b>The isometric twitch force and the tetanus force and fatigue index were decreased progressively in 28-day unloaded mice soleus, with the increase in fast twitch fiber subtype and the decrease in slow twitch fiber subtype.</p><p><b>CONCLUSION</b>The alteration of contractile characteristics is relevant to the slow-to-fast fiber conversion in mice soleus after 28-day hind-limb unloading.</p>
Subject(s)
Animals , Mice , Hindlimb Suspension , Physiology , Mice, Inbred C57BL , Muscle Contraction , Physiology , Muscle Fatigue , Physiology , Muscle Fibers, Fast-Twitch , Physiology , Muscle Fibers, Slow-Twitch , Physiology , Muscle, Skeletal , Pathology , Physiology , Muscular AtrophyABSTRACT
The purpose of this study is to identify the electrical activity of neuron, the existence of the transition from bursting pattern to spiking pattern and the ion mechanism of the bursting pattern. The intracellular electrical activity patterns of single neurons in the stomatogastric ganglion (STG) of crayfish were recorded when the extracellular calcium concentration ([Ca(2+)](o)) or calcium-dependent potassium channel blocker tetraethylammonium concentration ([TEA](o)) were changed, using intracellular recording method. These single neurons were also functionally isolated from the ganglion by application of atropine and picrotoxin which could block the inhibitory acetylcholine synapses and glutamatergic synapses respectively. When [Ca(2+)](o) was decreased by increasing EGTA, the membrane potential of the neuron was increased, and the electrical activity patterns were changed from the resting state with lower potential value (resting state of polarization) to the bursting pattern firstly, and then to the spiking pattern, at last to the resting state with higher potential value (resting state of depolarization). When [TEA](o) was increased, the membrane potential of the neuron was increased, and the electrical activity pattern was changed from the resting state with lower potential value (resting state of polarization) to the bursting pattern firstly, and then to the spiking pattern. The duration of the burst of the bursting pattern was increased. When [Ca(2+)](o) was increased or [TEA](o) was decreased, an inverse procedure of the electrical activity pattern was exhibited. On one hand, the results indicate that a single neuron can generate various electrical activity patterns corresponding to different physiological conditions, and the regularity of the transitions between different electrical activity patterns. On the other hand, the results identify that the initiation and termination of the burst in bursting pattern are determined by calcium-activated potassium conductance, which is adjusted by intracellular calcium concentration influenced by inward calcium current. It may be the ionic mechanism of generation of the bursting pattern in a single neuron.