ABSTRACT
Objective To observe erythropoietin (EPO) and its mRNA expression changes in rats cortical neurons when suffering hypoxia and investigate the endogenous EPO protective effect of hypoxia neuronal cells.Methods Cultured cortical neurons were prepared from hypoxia rats and divided into control,hypoxia 12,24,48,72 h group.Using immunohistochemistry,reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot,we observed EPO and its mRNA expression in cells,and also observe the culture medium containing lactate dehydrogenase to evaluate the activity of neurons in the whole process.Results Immunohistochemistry,RT-PCR and Western blot analysis showed:the EPO (20.79 ± 2.98) and its mRNA (0.78 ± 0.05) at 12 h had a basic expression in hypoxia group,compared with the control group (EPO:17.12 ± 1.99; mRNA:0.39 ± 0.05),and the difference was statistically significant (t =2.51,P ＜ 0.05 ; t =13.51,P ＜ 0.01) ; the strongest expression was observed at 48 h (EPO:28.88 ± 3.41,mRNA:1.45 ± 0.07),the difference was statistically significant (t =7.29,P ＜ 0.01 ; t =33.24,P ＜ 0.01) ; and neuronal activity was strongest.Lactate dehydrogenase activity was significantly decreased after hypoxia 72 h,and also a statistically significant difference was found between the groups at each point.Conclusions The EPO and EPO mRNA expression are increased after hypoxia in neuron cells,and may enhance the activity of neurons.Our study suggests that EPO might be involved in the development process of neuronal hypoxia and play an important role in neuronal hypoxia process.
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Objective To investigate the variations of surface protein genes of avian influenza virus (AIV)before and after infecting mouse.Methods Mouse lung tissue was infected with A/Goose/Guangaong/NH/2003(H5N1)and the virus was isolated 12 hours and 9 days after replication in lung tissue of mouse.The isolated strains were amplified in embryonated chicken eggs,anti the virion RNA was transcribed into cDNA by reverse transeriptase.After amplification and purification,dideoxy-mediated chain termination was performed to detect synthetic oligonucleotide primers and DNA sequence was analyzed.Results The homology of nucleotide sequence for HA gene of three isolated strains was 99.6%-99.8%.and that of amino acid sequences was 99.3%-99.6%.The homology of nucleotide sequence for NA gene of three strains was 99.8%-99.9%.all of them were synonymous mutatinns.No variation was found in M gene.Conclusion After replication in mouse lung tissue,no significant mutation was found in the surface protein genes of AIV except some point mutations in HA genes.
ABSTRACT
Objective To study the expression of hypoxia inducible factor-1 alpha(HIF-1?) and HIF-1? mRNA after focal cerebral ischemia reperfusion in rats.Methods Adult male SD rats were divided into six groups: sham operation group,5 groups of ischemia/reperfusion(the rats undergoing 2-hour ischemia and then 6-hour,1-day,2-day,3-day and 4-day reperfusion),with 6 rats in each group.Middle cerebral artery occlusion(MCAO) was set up in male SD rats according to Longa' method.The cerebral tissues were analyzed with immunohistochemical methods.The level of HIF-1? protein by immunohistochemical methods and the level of HIF-1? mRNA by in situ hybridization and RT-PCR were detected in the brain tissues.Results HIF-1? protein expression started at 6 h after reperfusion,increased remarkably on day 1,reached the peak on day 3,then declined markedly on day 4.HIF-1? mRNA increased at 6 h after reperfusion,peaked on day 3,then declined on day 4.HIF-1? expression was mainly in the periphery of infarcted area at each time point.Conclusion High expression of HIF-1? during focal cerebral ischemia/reperfusion in the rat brain tissues,suggests that HIF-1? has neuroprotective effect against cerebral ischemic injury.