A method for culturing neonatal mice cardiomyocytes in vitro and its applications in toxicity evaluation / 军事医学科学院院刊

Objective To establish a method for culturing neonatal mice cardiomyocytes, and construct an in vitro model of cardiomyocytes for assessing the cardiac toxicity of chemicals. Methods Hearts of neonatal mice of 1 day old were digested with enzyme mixture of trypsin/collagenase type Ⅱ/dispase and the cell suspensions were pre-plated to flask for a short time and then seeded on coated dishes. The cultured cells were treated with 5-fiuorine-deoxy-uridine(15 μg/ml)and uridine(35 μg/ml)to enrich cardiomyocytes that were identified according to the morphology and immunocytochemistry of α-actin antigen. Cardiac myocytes were incubated with 0-64 μg/ml of a fusarium mycotoxin butenolide(BUT) for 12 h. Cell viability was then evaluated by MTT assay. Microscopic observation showed that BUT induced significant morphological changes including cellular swelling, vacuolation and breakage of muscle fibers. Results It was found that 96% of the cultured cells were cardiomyocytes and the myocytes kept beating after 90 days of culture. Concentration-dependent decreases in cell viability following exposure of cardiac myocytes to BUT were observed. Conclusion The results indicated that relatively pure primary culture of neonatal mice cardiomyocytes is successfully established. BUT possesses the potential to induce myocardial toxicity.

Effects of ginkgolide B against damage of cultured hippocampal neurons caused by glutamate / 中国应用生理学杂志

<p><b>AIM</b>To investigate protective effects of ginkgolide B (GB) in different administration modes on glutamate-induced neuronal damage.</p><p><b>METHODS</b>Essential GB were obtained by supercritical CO2 fluid extraction. Glutamate excitotoxicity were examined in primary cultures from neonatal Wistar rat, by using of Trypan blue dye staining, testing the lactate dehydrogenase leakage from cultured neurons and terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) method. The protective effects of GB in different administration modes (pre-treatment and post-treatment) were adopted and compared with the NMDA receptor uncompetitive antagonist-MK-801 in acute-treatment.</p><p><b>RESULTS</b>Treatment with GB in two administration modes both could increase ratio of surviving neuron, decrease LDH efflux and reduce ratio of neuron apoptosis in different degree, depended on dose in certain range. The protective effect of pre-treatment was superior to post-treatment, but inferior to MK-801.</p><p><b>CONCLUSION</b>GB can protect neurons against glutamate damage, and preventive using has more efficiency. The potential mechanism of its neural protection may be not only related to PAF receptor. If the predominant protection effect of GB in pretreatment is considered, precautionary intervention to high-risk population could have more value.</p>

Protective effect of Quinacrine on striatum neurons from heat treatment injury / 中国应用生理学杂志

<p><b>AIM</b>To study the protective effect of Quinacrine(QA) on rat striatum neurons from the injury caused by heat environment treatment, to probe the relationship between cell membrane injury and cellular injury protection, and to seek the possibility of QA as a preventive agent to heat injury.</p><p><b>METHODS</b>Primary cultured striatum neurons from newborn rats were pretreated with QA at different concentration for 1 h, and then heat-treated at 43 degrees C for another 1 h. Cell necrosis was detected by Trypan blue staining, and apoptosis was evaluated through Activated Caspase-3 dye and TdT dye.</p><p><b>RESULTS</b>Heat treatment effected the survival of striatum neurons and resulted in great number of cell death, which was mainly mediated by cell necrosis process. It was shown that treatment of QA itself had little effect on the survival of striatum neurons, while QA pretreatment decreased cellular necrosis caused by following heat treatment.</p><p><b>CONCLUSION</b>QA protects striatum neurons from heat environment injury at about 20 pmol/L, and the protection may mediated by reduction of necrosis.</p>

Effects of hypoxia on the proliferation of embryonic stem cells / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of hypoxia on the proliferation of mouse embryonic stem cells (mouse ES cells) in vitro.</p><p><b>METHODS</b>We observed the proliferation of ES cells by hematometery and BrdU-labeled flow cytometry (FCM), and we also detected the expression of hypoxia inducible factor-1a (HIF-1a) by RT-PCR.</p><p><b>RESULTS</b>(1) The number of ES cells after culturing in the hypoxia environment (3% O2 and 10% O2) for 24 hours were lesser than those in normoxia (20% O2). (2) The number of ES cells significantly increased after intermittent hypoxia (3% O2) stimulus for 10 minutes per day for 4 days. (3) We also observed the relation between the expression of HIF-1a and the proliferation of ES cells by RT-PCR. The results showed that the expression of HIF-1a had no significant change after ES cells were culturing in hypoxia environment (3% O2 and 10% O2) for 24 hours or in intermittent hypoxia (3% O2 and 10% O2) for 4 days.</p><p><b>CONCLUSION</b>These results suggest that intermittent hypoxia (3% O2) can significantly promote the proliferation of ES cells in vitro, while persistent hypoxia inhibits those, and the mechanism of these should be addressed in further.</p>

Effect of CoCl2 pretreatment on Na + and K+ currents of the rat hippocampal neurons after acute hypoxia / 中国应用生理学杂志

<p><b>AIM</b>To study effect of CoCl2 pretreatment on the voltage-gated Na+ and K+ currents of the rat hippocampal neurons after acute hypoxia.</p><p><b>METHODS</b>Primarily cultured hippocampal neurons were divided into CoCl2 pretreated and non-pretreated groups. Patch clamp whole cell recording technique was used to examine Na+ and K+ currents of the hippocampal neurons.</p><p><b>RESULTS</b>After acute hypoxia, I(Na) and I(K) of the hippocampal neurons were significantly decreased and the threshold of I(Na) was right-shifted. Pretreatment of the neurons with CoCl2 inhibited the reduction of I(Na) and I(K).</p><p><b>CONCLUSION</b>CcCl2 pretreatment alleviates the acute hypoxia-induced changes of I(Na) and I(K), which may be one of the mechanisms for the protective effect of CoCl2 on neurons.</p>

Effects of oxygen-glucose deprivation on cultured rat hippocampal neurons / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of oxygen-glucose deprivation on cultured rat hippocampal neurons.</p><p><b>METHODS</b>The hippocampal neurons cultured for 12 d were exposed to combined oxygen-glucose deprivation for 0.5 - 4 h and then cultured with original medium in normoxia for 28 h. Necrotic neurons were identified by 0.4% trypan blue staining and apoptotic neurons were detected by a TUNEL technique. Meanwhile, the area, perimeter and circle diameter of cell bodies were measured respectively by a photography analysis system.</p><p><b>RESULTS</b>The percentage of necrotic cells in cultured hippocampal neurons increased significantly during oxygen-glucose deprivation, but the percentage of apoptotic cells increased significantly after 28 h oxygen-glucose recovery. Photography analysis showed that area, perimeter and circle diameter of the necrotic cell bodies were larger than those of the apoptotic ones.</p><p><b>CONCLUSION</b>Oxygen-glucose deprivation can lead to severe damage of cultured hippocampal neurons. The necrosis is major during acute oxygen-glucose deprivation, while the apoptosis is major 28 h after oxygen-glucose recovery.</p>

Establishment of the model of oxygen-glucose deprivation in vitro rat hippocampal neurons / 中国应用生理学杂志

<p><b>AIM</b>To establish the model of oxygen-glucose deprivation in vitro rat hippocampal neurons.</p><p><b>METHODS</b>The hippocampal neurons cultured for 12 d were exposed to combined oxygen-glucose deprivation for 0.5-4 h and then cultured with original medium in normoxia for 24 h. Auto-biochemical analyzer determined LDH activity. The change of neuronal morphology and neuron survival were observed by converted contrast microscope and assessed by photography analysis system. Neuron apoptosis was detected by using the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nickel end labeling (TUNEL) method.</p><p><b>RESULTS</b>The neurons swelled, LDH release increased and neuron survival decreased after gradually oxygen-glucose deprivation. The percentage of apoptosis increased obviously 24 h after recovering the supply of oxygen and glucose.</p><p><b>CONCLUSION</b>The model of oxygen-glucose deprivation in vitro rat hippocampal neurons is established successfully by using the modified ACSF (artificial cerebral spinal fluid) with serum and glucose free.</p>

Effects of hypoxic-preconditioning on anoxic-tolerance and Jun expression in cultured rat hippocampal neurons / 中国应用生理学杂志

<p><b>AIM</b>To study the effects of hypoxic preconditioning on anoxic tolerance and Jun expression in cultured rat hippocampal neurons after anoxia/reoxygenation.</p><p><b>METHODS</b>12 day cultured hippocampal neurons in control and hypoxic preconditioning group were exposed to anoxic environment (0.90L/L N2 + 0.10 L/L CO2) for 4 h, and then reoxygenated for either 24 h or 72 h. The neurons were immunocytochemically stained using the antiserum against Jun. The number of survival neurons and the percentage of Jun expressing neurons were investigated.</p><p><b>RESULTS</b>The percentage of Jun expressing neurons induced by anoxia in hypoxic-preconditioning group was significantly less than that in control group. The number of survival neurons was more in the hypoxic-preconditioning group than that in control group after anoxic reoxygenation.</p><p><b>CONCLUSION</b>Hypoxic-preconditioning can induce the development of anoxic-tolerance in cultured hippocampal neurons. The decrease in Jun expressing neurons in hippocampus may be an adaptive reaction to acute anoxia.</p>

Relationship between enhanced anoxic tolerance induced by hypoxic preconditioning and Na+, K+ currents in cultured hypothalamic cells / 中国应用生理学杂志

<p><b>AIM</b>To investigate the relationship between enhanced anoxic tolerance induced by hypoxic preconditioning and Na+, K+ currents.</p><p><b>METHODS</b>After hypoxic preconditioning and acute anoxia the I(Na), I(K) were measured in cultured hypothalamic cells by patch-clamp whole cell recording technique.</p><p><b>RESULTS</b>The amplification of Na+ currents did not been significantly changed, but the amplification of K+ currents was in hypoxic preconditioning neurons; acute anoxia lead to the inhibition of Na+, K+ currents in the two groups, while Na+, K+ currents in non-preconditioned control group were inhibited severity than hypoxic preconditioning group.</p><p><b>CONCLUSION</b>It is presumed enhanced anoxia tolerance induced by hypoxic preconditioning may be related to the opening of K+ channels.</p>

Effects of anoxia/reoxygenation on Fos and Jun expression and apoptosis in cultured rat hippocampal neurons / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of anoxia/reoxygenation on Fos and Jun expression and apoptosis in cultured rat hippocampal neurons.</p><p><b>METHODS</b>The hippocampal neurons cultured for 12 d were exposed to anoxia environment (90% N2 + 10% CO2) for 4 h and then reoxygenated for 24 h and 72 h. The neurons were immunocytochemically stained using the antiserum against Fos and Jun, and the apoptosis were detected by using the terminal deoxynucleotidyl transferase mediated biotinylated deoxyuridine triphosphate nickel end labeling (TUNEL) method and flow cytometric analysis.</p><p><b>RESULTS</b>The percentage of Fos and Jun positive neurons and apoptosis neurons in cultured hippocampal neurons after anoxia/reoxygenation increased than those in control.</p><p><b>CONCLUSION</b>The occurrence of neurons apoptosis is related to the increase in Fos and Jun expression in cultured hippocampal neurons after anoxia/reoxygenation.</p>

CoCl2-induced enhancement of glucose transport activity in mediating hypoxic tolerance in cultured hippocampal neurons / 生理学报

The effect of CoCl(2) pretreatment on glucose transport activity of cultured newborn rat hippocampal neurons and its role in neuronal hypoxic tolerance were observed. The results showed that the 2-deoxy-D-[1-(3)H ]glucose uptake rate and the mRNA expressions of glucose transporters (GLUT1 and GLUT3) in the hippocampal neurons were significantly increased after a 24-hour pretreatment with CoCl(2). The cell injury induced by 6-hour or 8-hour hypoxic exposure was also greatly reduced by CoCl(2) pretreatment. The protective effect of CoCl(2) on the neurons was largely abolished by cytochalasin B, a specific inhibitor of glucose transporters. The results suggest that CoCl(2) can increase mRNA expressions of GLUT1 and GLUT3 and glucose transporter activity of the neurons, which may be an important mechanism for the increased tolerance of the neurons to hypoxia.

Effects of rhIL-6 on Bcl-2 and Bax expression and apoptosis after anoxia-reoxygenation in cultured rat hippocampal neurons / 生理学报

The purpose of the present study was to determine the effects of recombinant human interleukin-6 (rhIL-6) on the Bcl-2 and Bax expression and apoptosis after anoxia-reoxygenation in cultured rat hippocampal neurons. The control and rhIL-6 treated hippocampal neurons cultured for 12 d were exposed to anoxia environment (90% N2+10% CO2) for 2 and 4 h and then were reoxygenated for 24 and 72 h. The expression of Bcl-2 and Bax was revealed immunocytochemically using the antiserum against Bcl-2 and Bax. The apoptosis was examined by the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nickel end labeling (TUNEL) method and flow cytometric analysis. The results showed that in cultured hippocampal neurons the Bcl-2 expression decreased while Bax expression and the percentage of apoptotic neurons increased after anoxia-reoxygenation compared with those before anoxia. In comparison with the control, after anoxia-reoxygenation the Bcl-2 expression in hippocampal neurons was higher than that in rhIL-6 group; however the Bax expression and the percentage of the apoptosis were decreased in rhIL-6 group. It is suggested that rhIL-6 may play a role in protecting neurons from the damage induced by anoxia-reoxygenation.