ABSTRACT
<p><b>BACKGROUND</b>The mechanism of cerebral vasospasm following subarachnoid haemorrhage (SAH) is not understood. Here, we hypothesized that apoptosis of endothelial cells induced by p53 and its target gene em dash p53 upregulated modulator of apoptosis (PUMA) played an important role in development of cerebral vasospasm. We also observed the effects of a p53 inhibitor, pifithrin-alpha (PFT-alpha), on reducing the expression of p53 and PUMA, consequently decreasing the apoptosis of endothelial cells and alleviating cerebral vasospasm.</p><p><b>METHODS</b>Male Sprague-Dawley rats weighing 300-350 g were randomly divided into five groups: a control group (sham surgery), a SAH group, a SAH+dimethyl sulfoxide (DMSO) group, a SAH + PFT-alpha (0.2 mg/kg) group and a SAH + PFT-alpha (2.0 mg/kg) group. PFT-alpha was injected intraperitoneally immediately after SAH. Rats were sacrificed 24 hours after SAH. Western blot and immunohistochemical staining were used to detect the levels of p53, PUMA and caspase-3 protein. In addition, mortality and neurological scores were assessed for each group. Statistical significance was assured by analysis of variance performed in one way ANOVA followed by the Tukey test. The neurological and mortality scores were analyzed by Dunn's method and Fisher exact test, respectively.</p><p><b>RESULTS</b>After SAH, Western blot and immunohistochemical staining showed the levels of p53, PUMA and caspase-3 in the endothelial cells and the numbers of TdT mediated dUTP nick end labelling (TUNEL) positive endothelial cells were all significantly increased in the basilar arteries (P<0.05), but significantly reduced by PFT-alpha (P<0.05). These changes were accompanied by increasing diameters and declining wall thickness of basilar arteries (P<0.05), as well as reduced mortality and neurological deficits of the rats (P<0.05).</p><p><b>CONCLUSIONS</b>PFT-alpha could protect cerebral vessels from development of vasospasm and improve neurological outcome as well as reduce the mortality via suppressing apoptosis induced by p53 in the endothelial cells of cerebral vessels.</p>
Subject(s)
Animals , Male , Rats , Apoptosis , Benzothiazoles , Pharmacology , Therapeutic Uses , Blotting, Western , Disease Models, Animal , Endothelial Cells , Pathology , Rats, Sprague-Dawley , Subarachnoid Hemorrhage , Drug Therapy , Pathology , Toluene , Pharmacology , Therapeutic Uses , Tumor Suppressor Protein p53 , Physiology , Vasospasm, IntracranialABSTRACT
<p><b>BACKGROUND</b>The fat derived protein adiponectin plays an important role in the regulation of glucose metabolism. The aim of this study was to provide the experimental basis for further investigating on adiponectin (ADPN) function. Its eukaryotic recombinant was constructed and expressed in precursor cells of 3T3-L1 adipocytes. The effects of dexamethasone on peroxisome proliferator activated receptor-gamma (PPAR-gamma) mRNA expression in 3T3-L1 cells with human recombinant adiponectin were assessed.</p><p><b>METHODS</b>The recombinant plasmid pMD18-T-hADPN and eukaryotic expression vector pcDNA3.1(+) were digested by two restrictive endonucleases and adiponectin and linear pcDNA3.1(+) were obtained. Then, they were ligated and translated into JM109. The recombinant pcDNA3.1(+)-hADPN so obtained was identified by digestion by restrictive endonuclease and nucleotide sequencing. The 3T3-L1 precursor cells were transfected using SuperFect Transfection Reagent (Qiagen). Furthermore, 3T3-L1 cells with human recombinant adiponectin incubated with dexamethasone (0.5 mmol/L) for 24 hours, cells were collected and total RNA was extracted. The PPAR-gamma mRNA expression was quantified by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>After eukaryotic recombinant was digested by Hind III and EcoR I, fragments of 800 bp and 5.4 kb were identified by nucleotide sequence scanning and consistent with theoretical values. Electrophoretogram of RT-PCR in 3T3-L1 precursors showed only one band in front of 250 bp, which was consistent with theoretical value 234 bp. In the 3T3-L1 cells, 3T3-L1 cells with plasmid and 3T3-L1 cells human recombinant adiponectin, treatment with dexamethasone (0.5 mmol/L) decreased PPAR-gamma mRNA expression compared to untreated controls (P < 0.01). Effect of dexamethasone on PPAR-gamma mRNA expression in 3T3-L1 cells was reversed by stably transfected human recombinant adiponectin.</p><p><b>CONCLUSION</b>The 3T3-L1 cells stably transfected human recombinant adiponectin had increased PPAR-gamma mRNA expression. Dexamethasone suppressed PPAR-gamma mRNA expression in the 3T3-L1 cells. Effect of dexamethasone on PPAR-gamma mRNA expression in 3T3-L1 cells was reversed by stably transfected human recombinant adiponectin.</p>