The impact of scavenger receptor class A typeⅠ/Ⅱ on lipid metabolism in mice

AIM: To investigate the impact of scavenger receptor class A type Ⅰ/Ⅱ(SR-A Ⅰ/Ⅱ) on the lipid metabolism in SR-A Ⅰ/Ⅱ gene deficient mice. METHODS: A probe of 660 bp fragment of SR-A Ⅰ/Ⅱ cDNA digested with PstⅠ and XhoⅠ from plasmid 122 was used to identify whether SR-A Ⅰ/Ⅱ had been knocked out in the tail DNA of the mutant(SR-/-) and control(SR+/+) mice by the method of Southern-blot analysis. The serum levels of triglycerides(TG), cholesterol(CH), low density lipoprotein(LDL), high density lipoprotein(HDL), apolipoprotein(Apo) A and ApoB of the mice fed with normal food and higher lipid food respectively were tested by biochemical method. RESULTS: The serum levels of LDL and body weights of group with SR-A Ⅰ/Ⅱ gene knocked out were higher than that of control group(P<0.05). Although the disorders of serum levels of LDL and body weights deteriorated after high lipid diet in both groups, the disorders in group of SR-/- were worse than those in control group(P<0.01). CONCLUSION: The results demonstrated that SR-A Ⅰ/Ⅱ were involved in the regulation of lipid metabolism, and SR-A Ⅰ/Ⅱ deficiency is harmful for removing LDL from blood circulation.     

Effect of homocysteine-mediated endoplasmic reticulum stress on lipid metabolism in hepatocytes

AIM: To explore the effect of homocysteine (Hcy)-mediated endoplasmic reticulum stress on lipid metabolism in hepatocytes.METHODS: HepG2 cells used in the study were treated with 5 mmol/L Hcy.The concentrations of Hcy,triglycerides (TGE) and cholesterol (CHO) in the cells were measured.In high methionine diet-induced hyperhomocysteinemia C57BL/6 mice,the concentrations of TGE and CHO in hepatocytes were analyzed.The mRNAs and proteins expressions of glucose-regulated protein 78 (GRP-78) and sterol regulatory element binding protein (SREBP-1) were also assessed.RESULTS: The concentrations of Hcy and lipids (TGE,CHO) in HepG2 cells at different time point were elevated after treated with 5 mmol/L Hcy (P<0.05,vs 0 hour).The levels of plasma Hcy and TGE or CHO in hepatocytes of high methionine diet mice at different time point were significantly increased (P<0.05,vs 0 week).However,the TGE and CHO levels in plasma had no change (P>0.05,vs 0 week).The mRNAs and proteins expressions of GRP-78 and SREBP-1 in mice at different time point after high methionine diet were higher than that at 0 week (P<0.05).CONCLUSION: It suggests that Hcy-induced endoplasmic reticulum stress causes dysregulation of the endogenous sterol response pathway,also increases hepatic biosynthesis and uptake of TGE and CHO.     

Gene transfer and expression of recombined human proinsulin in hepatoma cells of rats

AIM:To explore the recombined human proinsulin gene containing glucose reaction element (GLRE) expression in transfected CBRH7919 cells. METHODS:The packaged retrovirus encoding genetically modified human proinsulin PLXSN-(GLRE)3-BP-1MpINS3 and PLXSN-(GLRE)3-BP-1MpINS2 were transfected into CBRH7919 cells. Insulin values in cells after transient and steady expression screened by G418 at different glucose levels were detected. Chromosome DNA was isolated from transfected and untransfected cells and polymerase chain reaction (PCR) was performed. PCR products were analyzed by electrophoresis. RESULTS:38 h after transfection, at the glucose levels of 0-25 mmol/L, the levels of insulin produced by cells including PLXSN-(GLRE)3-BP-1MpINS3 were (3.57±0.21)U/L, (5.30±0.20)U/L, (16.27±0.87)U/L, (23.23±1.12)U/L, respectively (P<0.05). One month after transfection, under above glucose levels, insulin values were (3.57±0.21)U/L, (5.30±0.20)U/L, (16.27±0.87)U/L, (23.23±1.12)U/L (P<0.05). CBRH7919 cells including PLXSN-(GLRE)3-BP-1MpINS2 secreted detectable insulin value at the level of 25 mmol/L, they were (2.10±0.23)U/L and (2.05±0.17)U/L, respectively. PCR products of transfected cells showed target band, but control cells did not. CONCLUSIONS:Recombined proinsulin gene was transfected successfully in CBRH7919 cells. The cells combined human proinsulin gene has the ability of producing insulin with increase in glucose concentration in vitro.     

IL-17A reduces lipid accumulation by up-regulation of ABCA1 expression in Raw264.7 macrophages

AIM:To investigate the effects of interleukin-17A (IL-17A) on the expression of adenosine triphosphate binding cassette transporter A1 (ABCA1) in RAW264.7 macrophages. METHODS:Mouse RAW264.7 macrophages were treated with IL-17A at different concentrations for 6 or 24 h, or treated with IL-17A at the same concentration for different time. The expression of ABCA1 at mRNA and protein levels was determined by RT-qPCR and Western blot, respectively. Cholesterol efflux to apolipoprotein A1 (ApoA-1) was evaluated by NBD-cholesterol method. Lipid accumulation in the cells was evaluated by Oil Red O staining. RESULTS:Compared with control group, IL-17A increased the expression of ABCA1 at protein level in the RAW264.7 cells significantly (P<0.05), but had no effect on the mRNA expression of ABCA1. In addition, cholesterol efflux to ApoA-1 was increased and lipid accumulation in the RAW264.7 cells was decreased obviously after treatment with IL-17A. CONCLUSION:IL-17A increases the protein expression of ABCA1 but not at mRNA level in the RAW264.7 macrophages, which may be correlated with its anti-atherosclerosis effect.     

Correlation between intraventricular pressure and early phase proto-oncogene expression in volume overload rats

AIM: To investigate the effect of intraventricular pressure change by volume overload (VOL) on expression of proto-oncogene c-fos,c-jun,c-myc and egr-1. METHODS: Left ventricular systolic pressure(LVSP) and left ventricular end diastolic pressure (LVEDP) of rat with VOL induced by aortacaval fistula operation and rats of control group were measured at 30 min, 1, 4, 6, 12 and 48 h after the operation,these mRNAs at the foregoing time points were measured by slot bloting method and quantified with densitometry. RESULTS: Be compared with the control group, VOL rats LVSP decreased (P＜0.05) and declined most remarkably at 48 h,LVEDP elevated significantly at 30 min (P＜0.05), reached a maximal value at 12 h and the levels of control group at 48 h (P＞0.05) after the operation.The proto-oncogene expression signals were not detected in the control,negative controls and VOL rats at 30 min after the operation. The c-fos,c-jun and egr-1 mRNA signals appeared earlier,at 1 h, and c-myc mRNA increased later at 4 h.All reached peak value at 4 h and then declined gradually.The c-fos mRNA were not detected at 48 h. The c-myc,c-0jun and egr-1 mRNA persisted throught the entire observation period from 1 h to 48 h. CONCLUSIONS: During VOL early phase the overload have effect on expression of the proto-oncogene mRNA,c-fos,c-jun and egr-1 mRNA appear earlier, c-myc later,egr-1,c-jun and c-myc persist longer period, but the expressions do not strengthen with the ventricule wall load increase.This sequential induction pattern may reflect the time course regularity of the proto-oncogenes expression induced by VOL,and indicate the proto-oncogenes expression initiate while the heart load accumulate some extent and duration and the load magnitude may not play a critical role.     

Alterations of cardiac sympathetic norepinephrine transporter expression in rats with volume overload

AIM: To determine the alterations of myocardial 1-adrenergic receptor (1-AR) and cardiac sympathetic norepinephrine transporter (NET) mRNA expression, which is upstream modulator of 1-AR, in rats with longterm volume overload (VOL). METHODS: Left ventricular systolic (LVSP) and end diastolic pressure (LVEDP) of rats with VOL induced by aortacaval fistula operation and control group were measured at 314,30and 60d after the operation, the mRNA at the time points was measured by RT-PCR and Northern blot analysis and quantified by densitometry. RESULTS: The cardiac sympathetic NET specific expression is in the cardiac sympathetic ganglia. Be compared with the control group, LVSP of VOL rats decreased most dramatically by 24% (P<0.05) at 3 d, after that LSVP increased gradually and were higher than control group at 60d. LVEDP increased initially compared with the control (P<0.05), the latter recovered to the control levels. RT-PCR and Northern blot showed that in VOL rats the NET mRNA did not decreased significantly from 3to 30d, and decreased remarkably at 60d after the operation (P<0.05). The pattern of 1-AR mRNA expression were similar to the NET. CONCLUSION: The results suggest decreased levels of NET mRNA may contribute to cardiac sympathetic dysfunction in heart failure due to longterm VOL, which may lead to decreased myocardial 1-AR mRNA. We conclude that the normal NET mRNA expression may play a critical role to maintain sensitivity of 1-AR to adrenergic stimuli and cardiac contractility.     

Erk1/2 MAP kinase mediates function of FGF21 to regulate hepatic lipid metabolism

AIM: To investigate whether attenuation of extracellular signal-regulated kinase 1/2 (Erk1/2), an MAP kinase, will affect the regulatory function of fibroblast growth factor 21 (FGF21) on hepatic lipid metabolism. METHODS: Male C57BL/6J wild-type (WT) mice (8 weeks old) were fed with high-fat diet (HFD) for 4 weeks, and then treated with U0126 (an MEK inhibitor, inactivating Erk1/2) and/or adeno-associated virus-FGF21 (AAV-FGF21) for 4 weeks. The change of hepatic lipid profiles and its relevant regulatory genes were evaluated. Meanwhile, the molecular mechanism was explored by in vitro study. RESULTS: Treatment with AAV-FGF21 significantly reduced serum trigly-ceride and total cholesterol levels in the HFD-fed WT mice. Moreover, AAV-FGF21 administration significantly decreased the expression of lipogenic regulatory gene Srebp-2, largely increased the expression of relevant genes including Acacb, ABCG5 and Cyp7a1, which were involved in fatty acid oxidation, cholesterol transport and bile acid production, and strongly inhibited the expression of hepatic inflammatory factors such as IL-1β, MCP-1 and TNF-α in the mice. However, these beneficial effects caused by AAV-FGF21 were strongly attenuated by U0126. On the other hand, in vitro experiments indicated that treatment with recombinant human FGF21 protein significantly down-regulated Srebp-2 expression at mRNA and protein levels in a dose- and time-dependent manner. These effects were abolished after U0126 administration. CONCLUSION: FGF21 improves the lipid metabolism in the liver, and Erk1/2 signaling partially regulates these biological effects of FGF21.     

Mutation of Npc1 gene causes abnormal lipid metabolism to induce apoptosis of renal cells and promote fibrosis

AIM: To investigate the dysfunction of renal cell and tissue in Npc1 mutant mice, in order to provide support for the treatment of Niemann-Pick disease type C1 (NPC1) patients.METHODS: The kidneys of wild-type (Npc1^+/+) and Npc1 mutant (Npc1^-/-) mice on postnatal day 60 were isolated. HE staining was performed to examine the morphological changes of the renal tissues. Oil red O staining was used to examine the lipid deposition in the renal tissues. The apoptosis of the renal cells was detected by TUNEL staining. The expression of apoptosis-related proteins in the renal tissue was determined by Western blot, and immunofluorescence was performed to examine the expression of α-smooth muscle actin (α-SMA) and vimentin in the renal tissues. RESULTS: Compared with Npc1^+/+ mice, the morphological observation showed obvious vacuoles and no lipid deposition in the renal tissue of Npc1^-/- mice. Subsequently, TUNEL staining showed significant increase in the apoptotic cells in the renal tissue of Npc1^-/- mice (P<0.01), and the expression levels of Bax and Bad were up-regulated in the renal tissues of Npc1^-/- mice (P<0.01), but Bcl-2 was down-regulated (P<0.05). Furthermore, the expression of α-SMA and vimentin was significantly up-regulated in the renal tissues of Npc1^-/- mice (P<0.01). CONCLUSION: Npc1 gene mutation causes abnormal lipid metabolism in the renal cells, which induces the apoptosis of renal cells and promotes the fibrosis of renal tissue.     

茄子反向温敏雄性不育系可溶性糖含量及相关基因表达分析

为揭示茄子反向温敏核雄性不育(rTGMS)发生与糖类代谢的关系,以茄子rTGMS系‘05ms’及温度不敏感系‘S63’为试材,对不育期和可育期的叶片及花蕾的可溶性糖含量进行比较,结果表明,‘05ms’在不育和可育时期叶片和花蕾中的可溶性糖含量均显著低于‘S63’;进一步对‘05ms’花蕾进行转录组测序及对其糖类代谢相关途径进行分析,发现差异表达基因主要富集在3个通路:淀粉和蔗糖代谢、糖酵解/糖异生和氨基糖和核苷酸糖代谢,其中淀粉和蔗糖代谢通路的差异基因最多且大部分在低温条件表达下调,主要影响了葡萄糖和半乳糖醛酸的合成。此结果初步揭示了茄子反向温敏雄性不育系中糖类代谢响应温度变化的特点,为茄子雄性不育杂交育种提供理论依据。     

OX1R expression in chronic ischemic brain tissue of rats

AIM: To study the orexin-1 receptor (OX1R) expression in chronic ischemic brain tissue of rats and the change following the ischemic process.METHODS: The cerebral ischemic model was established by ligating double carotid arteries in rats. The behavior of the models was evaluated by water maze. The OX1R expression was determined by immunohistochemical technique, and the location of OX1R expression was further confirmed by double immunofluorescent staining.RESULTS: The intelligence of rats 15 d after ligating double carotid arteries was impaired obviously, and improved in 1 month and 2 months compared with the model in 15 d. At the same time, the OX1R expression increased obviously from acute phase until 15 d of cerebral ischemia and decreased notably in 1 month compared to the model in 15 d, and then increased significantly for the second time in 2 months of model. From the histology, partial neurons of 15 d model rats got atrophy, and most neurons in 1 month model rats got cytomorphosis and atrophy, however partial neurons in 2-month model rats recovered normally. The OX1R expression was confirmed in neurons definitely by double immunofluorescent staining.CONCLUSION: During the pathologic process of chronic ischemic injury, orexin system has two-way regulatory functions through.     

Effects of intranasal Escherichia coli on glucolipid metabolism in high-fat diet-induced obese mice

AIM: To study whether the pulmonary infection of Escherichia coli (E. coli) interferes the glucolipid metabolism in high-fat diet-induced obese mice. METHODS: High-fat diet-induced obese mice (n=48) and normal chow-fed control mice (n=48) were intranasally infused with 40 μL fluid containing 4×10⁹ CFUs E. coli. The serum, periepididymal adipose tissue and liver were obtained at 0 d, 1 d, 2 d, 3 d and 4 d after infection. The body mass, periepididymal adipose tissue and liver were weighed, and the levels of fasting blood glucose (FBG), fasting blood insulin (FINS), free fatty acid (FFA) and very-low-density lipoprotein (VLDL) were measured by ELISA. The serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), and hepatic TG contents were detected, and the hepatic steatosis was observed under microscope with oil red O staining. RESULTS: Compared with day 0, the body mass, fat mass and fat index were decreased significantly from day 1 to day 4 after infection (P<0.05). The levels of FBG, FINS and HOMA-IR were apparently raised from day 2 to day 4 after infection (P<0.05). The contents of serum FFA, TG and VLDL were increased markedly from day 1 to day 4 after infection (P<0.05). However, the concentrations of serum TC, LDL-C and HDL-C were decreased obviously from day 1 to day 3 (P<0.05). The liver mass, liver index and TG content were significantly increased from day 1 to day 4 (P<0.05). Consistently, the lipid droplet accumulation in the liver cells was increased obviously at day 2 and day 4 after infection. Compared with control group, except the levels of serum TC, LDL-C and HDL-C in obese group substantially decreased, the other indexes were increased by different degrees during the whole experiment period (P<0.05). CONCLUSION: Pulmonary infection of Escherichia coli exacerbates the disorder of glucose and lipid metabolism in high-fat diet-induced obese mice, which contributes the development of insulin resistance and hepatic steatosis.     

Curcumin inhibits lipid peroxidation and the expression of TGF-β1 and PDGF in the liver of rats with hepatic fibrosis

AIM: To investigate changes of the level of reactive oxygen species (ROS),malondialdehyde (MDA),transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF) expression in a rat hepatic fibrosis model and the effect of curcumin ,and discuss the mechanism of the prophylactic effect of curcumin on hepa tic fibrosis.METHODS: Rat models of hepatic fibrosis were established by intraperitoneally injection of carbon tetrachloride.Curcumin of 20 mg,10 mg,5mg per 100 gram weight of rat was given to these rats respectively at the same time.Normal,fibrosis model and positive groups were made as controls.After eight weeks,all rats were executed and the blood and liver were kept.Serum level of ROS was tested by chromatometry.Content of MDA in liver homogenate was tested by thiobarbituric acid (TBA) method.Expressions of TGF-β1 and PDGF in liver were detected by immunohistochemical method. RESULTS: Serum level of ROS in fibrotic group increased significantly compared with that of normal group,and which was depressed obviously in curcumin groups(P＜0.05).Content of MDA in liver of curcumin group reduced significantly compared with that of fibrotic group (P＜0.01).Expressions of TGF-β1 and PDGF in fibrotic group increased significantly compared with those of normal group,which were depressed obviously in curcumin groups (P＜0.01).CONCLUSION: Curcumin could inhibit expression of TGF-β1,PDGF and lipid peroxidation in liver.These may be mechanisms of curcumin preventing hepatic fibrosis.     

Gene and protein alterations in the hippocampus of rats with temporal lobe epilepsy

AIM:To examine the expression profiles of both genes and proteins in hippocampus of rats with temporal lobe epilepsy (TLE) for revealing the molecular mechanisms of TLE and looking for the candidate targets and new therapeutic approaches in clinical practice.METHODS:Rat temporal lobe epilepsy was induced by administration of lithium chloride and pilocarpine (LiCl-PILO).The expression spectra of genes and proteins were constructed through the techniques of cDNA microarray,two-dimensional (2D) electrophoresis and Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).Subsequently,the differentially expressed genes and proteins were identified and analyzed.RESULTS:There were 192 genes of differential expression observed in hippocampal tissues of LiCl-PILO-induced temporal lobe epilepsy,and 159 genes have been registered in Genbank database,in which 84 genes were up-regulated while 75 genes were down-regulated.78 protein spots of differential display were screened out,in which 31 proteins were detected to be down-regulated and 47 were up-regulated.Finally,5 proteins were identified.CONCLUSION:These genes and proteins found in our study may play pivotal roles in the pathogenic mechanisms of epilepsy and may promise new therapeutic targets for refractory epilepsy in the future.     

Variation of brain derived neurotrophic factor and its mRNA expression in infancy rats after experimental bacterial meningitis

AIM: To investigate the expression and effect of brain derived neurotrophic factor (BDNF) mRNA and its protein in infancy rats after exposure to bacterial meningitis. METHODS: Three week old rats were used to construct the models of bacterial meningitis (n=30) and mormal(n=18). At 24 h, 48 h, 5 d after inoculating, the expression of BDNF mRNA and its protein were detected by in situ hybridization and immunohistochemical staining methods, respectively. RESULTS: The increase in BDNF mRNA expression was detected by in situ hybridization at 24 h in experiment(0.13320±0.02750) compared to control(0.06269±0.01147)(P＜0.01). Expression of BDNF mRNA was declined at 48 h, but its expression was still stronger than that in controls at 5 d(P＜0.05). The expression of BDNF protein was enhanced and reached to its zenith at 24 h in this experiment (0.16896±0.02717) (P＜0.01), compared to controls(0.08700±0.03413), and it declined after 48 h, then restored to the control levels at 5 d(P＞0.05). Meanwhile, in the brain from the experiment rats, strong positive hybridization and immunoreactivity were observed in the infiltrated inflammatory cells in leptomeninges, subarachnoid cavity, ventricles and brain parenchyma. CONCLUSIONS: These results support the hypothesis that BDNF might play a neuroprotective role in brain damage process in bacterial meningitis attacked rats. BDNF might take part in imune response. These results also support the hypothesis that BDNF has some relationships with other inflammatory mediators during acute inflammatory response of bacterial meningitis.     

Alterations in gene expression of series key enzymes in mevalonic acid pathway detected by RNA array in spontaneously hypertensive rats

AIM: To explore the alteration in gene expressions of several enzymes in mevalonic-acid (MVA) pathway in SHR.METHODS: 294 samples of total RNA were extrated from the tissues of ventriculum, aortic smooth muscle, liver and kidney in SHR and WKY. RNA array was used to determine the mRNA level of several enzymes in mevalonic acid pathway.RESULTS: (1) Systolic blood pressure of SHR surpassed that in WKY since the 6th week (P<0.01). (2) The level of cholesterol in serum was significantly lower in SHR than that in WKY (P<0.01), while that in tissue between two bands had no difference. (3) The gene overexpressions of four enzymes in the four tissues of SHR (P<0.01), including farnesyl diphosphate synthase (FDS), isopentenyl diphosphate isomerase (IDI), farnesyltransferase alpha subunit (FT1), farnesyltransferase beta subunit (FT2), which catalyze the vital mid-productions in MVA pathway, were observed. (4) Gene overexpressions of some enzymes assayed in MVA pathway in SHR renal tissue were observed since 4th week (P<0.01), including 3-hydroxy-3-methylglutaryl -coenzyme A reductase (HMGR), mevalonate kinase (MVK), mevalonate decarboxylase (MVD), squalene synthetase (SQS) and squalene epoxidase (SQ). (5) The gene expressions of these enzymes in ventriculum, aortic smooth muscle and liver showed no difference between two band rats, eg HMGR, MVK, MVD, SQS, SQ.CONCLUSION: The gene expressions of several enzymes in mevalonic acid non-cholesterol pathway in SHR ascend and the mechanism will be further explored.     

Isolation,cloning, and expression of five genes related to nitrogen metabolism in peach (Prunus persica L. Batsch)

An optimal dosage of nitrogen has long been known to play important roles in governing nitrogen-use efficiency and improving the yield of plants. However, there is limited information on the isolation and expression profiles of genes related to nitrogen metabolism in peach (Prunus persica L. Batsch). This study isolated five genes involved in nitrogen metabolism and evaluated the effects of a single foliar application of urea on levels of expression of these genes in the leaves of ‘Dazhenbaochiyue’ peach. Cloning resulted in the isolation of 1,767, 1,236, 1,074, 1,758, and 2,721 nt-long cDNAs with full-length open reading frames encoding 588, 411, 357, 585, and 906 amino acids representing the asparagine synthetase (AS), glutamate dehydrogenase (GDH), glutamine synthetase (GS), nitrite reductase (NiR), and nitrate reductase (NR) genes in peach, respectively. An alignment of multiple amino acid sequences revealed that the AS, GDH, GS, and NR proteins in peach shared high levels of sequence conservation or identity at the amino acid level with their homologues in Arabidopsis thaliana and grapevine (Vitis vinifera). Based on analyses of expression of the five genes in peach leaves, we demonstrated that genes related to nitrogen metabolism responded to a foliar application of urea within 2 d. This was consistent with previous reports which indicated that leaves rapidly absorbed urea-nitrogen after foliar application. Foliar application of 0.5% (w/v) urea inhibited expression of GS and NiR, but increased expression of GDH, AS, and NR compared to control leaves. The different patterns of expression of the five genes in this study suggested that their expression might reflect their various roles in nitrogen metabolism, plant N status, and responses to weather conditions such as high light intensity, temperature, or humidity, all of which affect photosynthesis. These findings provide a basis for future functional analyses of these five genes in peach.     

Construction of human era eukaryotic expression vector with EGFP tag and effects of human Era on cell morphogenesis and cell cycle

AIM: To construct eukaryotic expressive vectors of human era and analyze the effect of era on morphogenesis and cell cycle in vitro . METHODS: Two eukaryotic expressive vectors of EGFP-hEra fusion protein named pSMEGFP-hEra and pEGFP-C1-hEra were constructed and transfected into mouse fibroblast cell line NIH3T3 by way of lipofectin. Morphogenesis and cell cycle were analyzed by fluorescence microscopy and flow cytometer, respectively. RESULTS: Fusion protein of EGFP and human Era localized in cytoplasm around cell nucleus mainly. No morphologic change was examined, cell cycle analysis revealed the cell number of S phase lightly decreased. CONCLUSION: Human era may play a key role in cell cycle, these results may shed light on the further study of the function of this new gene.     

Effects of pioglitazone on myocardial energy metabolism and hemodynamics in rats with myocardial infarction

AIM: To observe the effects of pioglitazone on myocardial energy metabolism and hemodynamics in rats with heart failure after myocardial infarction (MI). METHODS: The model of MI was established by ligation of left anterior descending artery. The 20 surviving rats were randomly divided into MI group (n=10) and pioglitazone intervention group (P group,n=10, pioglitazone 3 mg·kg^-1·d^-1 orally). The sham-operated rats (SH, n=10) served as controls. Hemodynamic parameters were measured. The ratio of left ventricular weight to body weight (LVW/BW) and the ratio of right ventricular weight to body weight (RVW/BW) were calculated after 8-week treatment. The expression of PPARγ was examined by Western blotting. Mitochondrial respiratory function was determined by Clark oxygen electrodes. The size of adenine acid pool (ATP, ADP and AMP) in mitochondria was measured by HPLC. The adenine nucleotide translocator(ANT) activity was detected by the atractyloside-inhibitor stop technique. RESULTS: Compared with SH group, the protein expression of PPARγ was significantly decreased in MI group (P<0.01). The mitochondrial respiratory activity, the transport activity of ANT and the high-energy phosphate content were decreased in MI group (P<0.01), and the hemodynamic parameters were in disorder (P<0.01). Compared with MI group, the protein expression of PPARγ in P group was significantly increased. The mitochondrial respiratory activity, the high-energy phosphate content, the transport activity of ANT were improved (P<0.01). However, the hemodynamic parameters were not significantly changed.CONCLUSION: Pioglitazone increases the protein expression of PPARγ and improves myocardial energy metabolism in the development of heart failure in the rat model of myocardial infarction, but dose not change the hemodynamic parameters significantly.     

香蕉WAT1基因的鉴定及表达分析

【目的】基于香蕉基因组数据筛选Walls are thin 1(WAT1)基因,分析它们的序列及表达特性。【方法】以拟南芥WAT1为参考序列,通过本地Blast筛选获得香蕉WAT1基因,分析其核苷酸、启动子及编码蛋白特性,并利用实时定量PCR技术研究其在不同组织部位、不同激素和逆境胁迫处理下的表达情况。【结果】筛选获得5个香蕉WAT1基因(命名为MaWAT1-1~5)。蛋白亚细胞定位预测结果显示,MaWAT1-1、MaWAT1-2、MaWAT1-4主要定位在液泡和细胞膜上,MaWAT1-3主要定位在细胞质和细胞膜,MaWAT1-5定位在细胞膜和叶绿体。基因结构分析和系统进化树分析均将MaWAT1s分为两组,MaWAT1-1、MaWAT1-2、MaWAT1-4聚为一组(含6个外显子和5个内含子),MaWAT1-3和MaWAT1-5归为一组(含7个外显子和6个内含子)。启动子顺式作用元件分析结果显示:MaWAT1s启动子含有大量激素和胁迫响应相关元件。实时定量PCR结果显示,MaWAT1-4在叶片中表达量最高,MaWAT1-1在根和假茎中表达量最高,其余均在根中表达量最高;大多数MaWAT1s的表达受GA3、SA、盐胁迫和干旱等显著诱导,受高温显著抑制,同时部分成员的表达受IAA、ABA、JA、低温、机械损伤和枯萎病影响显著。【结论】MaWAT1s的表达受多种激素和逆境影响显著,可能在香蕉生长发育和抗逆防御反应中发挥着重要作用。