Effect of hyperbaric oxygenation on neural stem cells and myelin in neonatal rats with hypoxic-ischemic brain damage / 中国当代儿科杂志

<p><b>OBJECTIVE</b>This study investigated the effect of hyperbaric oxygenation (HBO) on neural stem cells (NSCs) and myelin in neonatal rats following hypoxic-ischemic brain damage (HIBD) and aimed to explore the possible mechanism of the protective effect of HBO on HIBD.</p><p><b>METHODS</b>Seven-day-old Sprague-Dawley rat pups were randomly assigned into 4 groups: Normal control, HIBD, hyperbaric air (HBA), and HBO groups (n=30 each). The HIBD model was produced by permanent occlusion of the left common carotid artery and 2 hrs hypoxemia exposure (8% O2 at 37 degrees C). HBA and HBO treatment was administered (2 ATA, once daily for 7 days) in the HBA and HBO groups respectively 1 hr after HIBD. BrdU immunohistochemistry was used to detect the NSCs in the sub-ventricle zone (SVZ) of the lateral ventricle and the dentate gyrus (DG) of the hippocampus. The myelin damage was assessed by myelin basic protein (MBP) immunostaining.</p><p><b>RESULTS</b>The BrdU-positive cells in the SVZ and the DG of the ischemic hemisphere in the HIBD group were dramatically decreased compared with those of the Normal control group at 3 weeks post-HIBD (P < 0.01). The HBO treatment resulted in an increase of BrdU-positive cells in the DG from 153.7 +/- 37.0 to 193.7 +/- 38.8 (P < 0.05). The nestin expression in the HIBD and HBA groups was reduced compared with that in the Normal control group. There was no difference in the nestin expression between the HBO and the Normal control groups. Hypoxia-ischemia (HI) led to marked myelin damage at 1 week post-HIBD. HBO or HBA treatment alleviated the damage.</p><p><b>CONCLUSIONS</b>The HBO treatment can result in the proliferation of BrdU-positive cells and alleviate the myelin damage following HIBD in neonatal rats, thereby offering neuroprotectivity against HI insults.</p>

Effect of adenovirus-mediated p27 gene expression on the proliferation and apoptosis of HL-60 and Raji cell lines / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>p27 is an essential mediator of cell cycle control, which plays a key negative role in the proliferation and tumorigenesis of certain cell types. Here, we designed this study to explore the possible effects of p27 on the proliferation and apoptosis of HL-60 and Raji cell lines.</p><p><b>METHODS</b>HL-60 and Raji cells were transfected with p27 via an adenovirus-mediated approach. The efficiency of Adp27 infection and the expression of p27 mRNA and protein were evaluated by X-gal staining, RT-PCR, and flow cytometry. The proliferation and apoptosis of HL-60 and Raji cells were estimated by means of trypan blue staining, MTT assay, Annexin V/PI, and DNA ladder electrophoresis.</p><p><b>RESULTS</b>The infection efficiencies in HL-60 and Raji cells were 40.3% and 32.0%, respectively. RT-PCR and flow cytometry showed that there was significant expression of p27 mRNA and protein in HL-60 and Raji cells infected with Adp27; on the other hand, uninfected HL-60 cells showed faint traces of p27 mRNA and protein and Raji cells showed nearly no signs of p27 mRNA and protein. As demonstrated by a cell growth curve and by an MTT assay, strong time-dependent proliferation inhibition was apparent in HL-60 and Raji cells infected by Adp27. After 72 hours of infection, the Annexin V+/PI- apoptotic cell rates in HL-60 and Raji cell lines were 46.9% and 35.7%, respectively, significantly higher than in the control groups (4.7% and 5.6%, respectively). Typical DNA ladder bands were detectable in HL-60 and Raji cells after 48 hours of Adp27 infection.</p><p><b>CONCLUSIONS</b>Adenoviral vector-mediated p27 gene transfection of HL-60 and Raji cells leads to the inhibition of cellular proliferation and the promotion of cell apoptosis. This technique may provide an approach to gene therapy for leukemia or lymphoma.</p>

Effect of HMBA on differentiation and apoptosis of HL-60 and U937 cells and its mechanism / 中华血液学杂志

<p><b>OBJECTIVES</b>To explore the effect of hexamethylene bisacetamide (HMBA) on the differentiation and apoptosis of HL-60 and U937 cells, and its mechanism.</p><p><b>METHODS</b>Flow cytometry was used to evaluate the expressions of cellular surface antigen CD(11b), CD(14), apoptotic marker Annexin V, cell cycle distribution and endocytic antigen cyclin D, cyclin E and p27. Changes of c-myc, Rb, Bcl-2 gene mRNA levels were detected by RT-PCR.</p><p><b>RESULTS</b>After 72 hours of HMBA treatment, CD(11b) expressions increased significantly, apoptosis increased under high-dose HMBA, cells were arrested in G(0)/G(1) phase and reduced cyclin E, increased cyclin D and p27 were significant in a dose-dependent manner in HL-60 and U937 cells. RT-PCR showed that c-myc and bcl-2 mRNA was significantly down-regulated and Rb mRNA up-regulated in HL-60 and U937 cells.</p><p><b>CONCLUSION</b>HMBA can induce the differentiation of HL-60 and U937 cells, while apoptosis of these cell is induced only by high dose of HMBA. The possible mechanism of HMBA inducing differentiation might be related to the changes of cell cycle regulators and certain proliferation and differentiation related genes.</p>

Effects of hexamethylene bisacetamide on cell cycle and expression of its regulatory proteins in HL-60 cells / 中国实验血液学杂志

Hexamethylene bisacetamide (HMBA) is referred as a differentiation-inducer for the clinical treatment of acute myeloid leukemia and myelodysplastic syndrome. However, the molecular mechanism of the effects of HMBA on myeloid leukemic cells remains unknown. In this study, the effects of HMBA on cell cycle and expression of cell cycle regulatory proteins in HL-60 cell were investigated in order to explore its pharmacological mechanism. The altered distribution of cell cycle and expression of its regulatory proteins (cyclin D, cyclin E and p27) in HL-6 0 cell induced by HMBA were analyzed by flow cytometry. The effects on transcription for mRNA of CKI p15, p16 and p27 in HL-60 cell were further studied by RT-PCR. The results showed that HMBA could mainly commit HL-60 cell to G0/G1 arrest and the significantly decreased endocytic cyclin E protein and increased cyclin D/p27 protein after HMBA treatment were found. There was no expression of p15, p16 mRNA in untreated HL-60 cell and 3 mmol/L of HMBA could make them expressed after exposed for 24 h or 48 h respectively. The expression of p27 mRNA was positive and no obviously different in untreated HL-60 cells exposed for 24 h, 48 h and 72 h. These results suggested that one of the pharmacological mechanisms of HMBA was to elevate the expression of p27 and reduce the cyclin E expression as well as to activate the expression of p15, p16 gene mRNA, that arrested cell at G0/G1 and exerted its effects of anti-proliferation.