The effect of captopril and losartan on paraquat-induced pulmonary fibrosis and PlGF expression in the lungs of rats / 中华劳动卫生职业病杂志

Objective@#To investigate the dynamic expression of placenta growth factor (PlGF) in the lungs and its role in paraquat-induced pulmonary fibrosis and to evaluate the effect of ACEI captopril and AT (1) -receptor blocker losartan on paraquat-induced pulmonary fibrosis.@*Methods@#84 adult healthy female Sprague-Dawley (SD) rats were randomly divided into four groups of different treatments designated as: Control, PQ alone (PQ) , captopril treatment, losartan treatment. Each group was divided into three subgroups of seven animals each. The animals were killed at either 7, 14 or 28 days after PQ administration. The rats in PQ group, treatment group were treated intragastrically (ig) with PQ (40 mg/kg) and the rats in control group were treated with the same dose of saline at the beginning of the experiment. The treatment group received Captopril (60 mg/kg; ig) or Losartan (10 mg/kg; ig) once a day respectively after PQ administration and the other two groups received saline. At the given timepoint, animals were sacrificed and lungs were harvested. A semiquantitative assay of histological examination, hydroxyproline in lung tissues were used to determine the severity of alveolitis and fibrosis. RT-PCR and immunohistochemistry were used to detect the mRNA and protein expression of PlGF.@*Results@#Inflammatory cell infiltration and fibrotic scores were more prominent in the model group, hydroxyproline contents in lung tissue were significantly increased after PQ administration compared to the control group. Captopril, losartan apparently attenuated the degree of lung injury and pulmonary fibrosis. On 7th, 14th days, the levels of alveolitis in the intervention groups were significantly alleviated as compared with the model group (P<0.05) . On 28th days, the levels of pulmonary fibrosis in the intervention groups were significantly alleviated as compared with model group (P<0.05) . The hydroxyproline contents in the intervention groups were significantly decreased as compared with model group (P<0.01) . PlGF mRNA on day 7, 14, 28 (1.28±0.29vs0.10±0.01、0.80±0.07vs0.10±0.01、0.65±0.13vs0.10±0.01) in the PQ group were all upregulated as compared with that of the control group. PlGF mRNA on day 7, 14, 28 in the captopril and Losartan intervention groups were significantly decreased (0.94±0.04、0.71±0.09、0.52±0.24 and 0.80±0.12、0.66±0.11、0.51±0.03) . PlGF positive expression index on day 7, 14, 28 (2.27±0.34 vs0.13±0.01、1.78±0.41 vs0.14±0.03、1.25±0.69 vs0.13±0.01) in the PQ group were all upregulated as compared with that of the control group. PlGF positive expression index on day 7, 14, 28 in the captopril and Losartan treatment groups were significantly decreased (1.53±0.78、1.17±0.79、0.97±0.61 and 1.36±0.63、1.24±0.80、0.83±0.47) . PlGF positive expression index on day 7 in the two intervention groups were significantly decreased, as compared with PQ group (P<0.05) .@*Conclusion@#PlGF may plays an important role in the development of pulmonary fibrosis following paraquat-induced lung injury in rats. Captopril and losartan had an inhibitory effect on paraquat-induced pulmonary fibrosis, and the effect may be due to inhibition of angiotensin II and, in part, be associated with reduction in PlGF.

Inhibitory effects of Beclin 1 gene expression by RNA interference on the proliferation and apoptosis in fibroblasts of naked mole rat / 中国实验动物学报

Objective To investigate the effects of down-regulation of Beclin 1, which is an autophagy regulatory molecule, expression induced by RNA interference on the proliferation and apoptosis in skin fibroblasts of naked mole rat. Methods The expression levels of Beclin 1 were detected after starvation or H2 O2 treatment.The fibroblasts were transi-ently transfected with specific siRNA targeting Beclin 1 and then screened by real-time PCR and Western blot.Cell prolifer-ation and apoptosis were determined using CCK-8 detection kit and flow cytometry ( FCM ) .The expressions of related genes were detected by Western blot.Results The expression of Beclin 1 gene at mRNA and protein levels was signifi-cantly lower in fibroblasts of the naked mole rat.Starvation and H2 O2 treatment induced changes of the Beclin 1 expression. Inhibition of Beclin 1 gene expression can inhibit cell proliferation and induce early and late apoptosis.The protein levels of p53, BAX, Bcl2, LC3B, p-AKT and mTOR were reduced after transient transfection with Beclin 1-siRNA.Conclusions The expression of Beclin 1 in fibroblasts of naked mole rat are changed in response to starvation or H2 O2 stimulation.Inhi-bition of Beclin 1 gene expression can inhibit cell proliferation and induce apoptosis.Therefore, Beclin1 gene may play a regulatory role in autophagy, proliferation and apoptosis in the skin fibroblasts of naked mole rat.

Neural stem cell-specific peroxisome proliferator-activated receptor γ knockout mice: breeding and genetic identification / 南方医科大学学报

<p><b>OBJECTIVE</b>To breed neual stem cell-specific peroxisome proliferator-activated receptor γ (PPARγ) knockout mice.</p><p><b>METHODS</b>Two transgenic mouse models, namely B6.PPARγloxp/loxp and B6.Nestin-Cre were interbred, and the first- generation offsprings were backcrossed with B6.PPARγloxp/loxp to obtain the second-generation mice. Genomic DNA was extracted from the second-generation mice for PCR to amplify the loxp and Cre gene fragments followed by agarose gel electrophoresis to verify their sizes. The mice with the PPARγloxp/loxp.Nestin-Cre (KO) genotype were selected as the neural stem cell-specific knockout PPARγ mice, with B6.PPARγloxp/loxp (loxp) mice as the control. Tissue samples were collected from specific regions of the mouse brain and peripheral tissue for detecting the expression of PPARγ mRNA using RT-PCR and real-time quantitative PCR.</p><p><b>RESULTS AND CONCLUSION</b>Genotyping results showed PPARγloxp and Cre bands in the knockout mice, which showed obviously decreased mRNA expression of PPARγ, suggesting successful establishment of neural stem cell-specific PPARγ knockout mice. The two transgenic mice we used were fertile, and their breeding pattern followed the laws of Mendelian inheritance.</p>

miR-124a promotes neurite outgrowth by inhibiting iASPP expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of iASPP as the target gene of miR-124a in neural development.</p><p><b>METHODS</b>Using the online bioinformatical tool (TargetScan) and by reviewing the relevant studies, we selected iASPP as the candidate target gene of miR-124a involved in early-stage neuronal differentiation. Luciferase reporter assay was used to verify the candidate gene. We transfected M17 cells with a miR-124a overexpression plasmid and detected the changes in the protein expression of iASPP using Western blotting. With retinoic acid-induced M17 cells as the neuronal differentiation model, the role of iASPP in early-stage neuronal differentiation was investigated by gene overexpression and gene interference techniques.</p><p><b>RESULTS</b>miR-124a inhibited the expression of iASPP in M17 cells by interacting with the 3'UTR of iASPP gene. miR-124a promoted neurite outgrowth of the cells, which was blocked by iASPP overexpression.</p><p><b>CONCLUSION</b>miR-124a promotes neurite outgrowth of M17 cells by inhibiting iASPP expression.</p>

Effects of peroxisome proliferator-activated receptors γ on the expression of insulin receptor substrate-4 gene in rat cortical neurons and mouse brain / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of peroxisome proliferator-activated receptors γ (PPARγ) on insulin receptor substrate-4 (IRS-4) gene expression in the brain.</p><p><b>METHODS</b>Primarily cultured cortical neurons from E17-18 Sprague Dawley rats, after 1 week of plating, were exposed to 10 µmol/L PPARγ agonist rosiglitazone for 0, 1, 4 or 24 h. Adult C57BL/6J mice or conditional brain PPARγ knock-out mice (B-PPARγ-KO, BKO) received an intraperitoneal injection of rosiglitazone in 10% DMSO at 12 mg/kg or injection of the same volume of saline containing 10% DMSO. The effect of rosiglitazone on the survival of the neurons was examined by MTT assay. The expression of IRS-4 mRNA was analyzed by real-time quantitative PCR.</p><p><b>RESULTS</b>The survival of the cortical neurons showed no significant difference between the agonist groups and the control group. The expression of IRS-4 mRNA was significantly up-regulated in the cortical tissues and neurons of the agonist groups compared with the control groups (P<0.05), but in BKO mice without treatment, IRS-4 mRNA expression was significantly down-regulated (P<0.05).</p><p><b>CONCLUSION</b>PPARγ can enhance the expression of IRS-4 mRNA in the brain.</p>

Expression of livin in lung cancer tissue and its relationship with the expression of caspase-3 / 中国肺癌杂志

<p><b>BACKGROUND</b>Livin is a novel inhibitor of apoptosis protein(IAP),recent studies showed that it overexpressed in many carcinomas including lung cancer and contributed much to the cancerous development.The objective of this study is to explore the expression of the two isoforms of livin in lung cancer tissues and their relationship with histological types and chemotherapy,and to explore their relationship to the expression of caspase-3 as well.</p><p><b>METHODS</b>Expression of livin α,livin β and caspase-3 mRNAs were detected by reverse transcription polymerase chain reaction(RT-PCR) assay in lung cancer tissues as well as in controls.</p><p><b>RESULTS</b>Livin α and livin β were expressed in 12 of 27 and 19 of 27 lung cancer tissues respectively,much higher than those in lung para-cancerous(0/6,0/6) or benign disease lung tissues(0/12,1/12)(both P < 0.01).Moreover,the positive rate was 7/14 and 9/14 in lung adenocarcinoma and 4/12 and 9/12 in squamous and large cell carcinoma respectively,and both of them were detected in one small cell carcinoma.The levels of these two isoforms in lung cancer were significantly higher than those in controls by Gel Imaging System(both P < 0.05),the level of livin α was remarkably higher in adenocarcinoma than that in squamous cell carcinoma(P < 0.05),while the level of livin β was similar in both carcinomas(P > 0.05).Meanwhile,the level of caspase-3 in lung cancer was significantly lower than that in controls,the levels of either each of two isoforms or their sum were negatively associated with that of caspase-3(P < 0.05,P < 0.01,P < 0.01).Two isoforms of livin mRNA expression seemed to increase after chemotherapy but not related to clinical stages(P > 0.05).</p><p><b>CONCLUSIONS</b>Two isoforms of livin are differently expressed in different histological types of lung cancer and may contribute to corresponding cancerous development;the levels of livin are negatively associated with those of caspase-3,this may due to the fact that livin could resist against apoptosis;high expression of livin seems to be related to chemotherapy but not clinical stage.</p>