Identification of G2/M phase transition by sequential nuclear and cytoplasmic changes and molecular markers in mice intestinal epithelial cells.

Although the regulatory network of G2/M phase transition has been intensively studied in mammalian cell lines, the identification of morphological and molecular markers to identify G2/M phase transition in vivo remains elusive. In this study, we found no obvious morphological changes between the S phase and G2 phase in mice intestinal epithelial cells. The G2 phase could be identified by Brdu incorporation resistance, marginal and scattered foci of histone H3 phosphorylated at Ser10 (pHH3), and relatively intact Golgi ribbon. Prophase starts with nuclear transformation in situ, which was identified by a series of prophase markers including nuclear translocation of cyclinB1, fragmentation of the Golgi complex, and a significant increase in pHH3. The nucleus started to move upwards in the late prophase and finally rounded up at the apical surface. Then, metaphase was initiated as the level of pHH3 peaked. During anaphase and telophase, pHH3 sharply decreased, while Ki67 was obviously bound to chromosomes, and PCNA was distributed throughout the whole cell. Based on the aforementioned markers and Brdu pulse labeling, it was estimated to take about one hour for most crypt cells to go through the G2 phase and about two hours to go through the G2-M phase. It took much longer for crypt base columnar (CBC) stem cells to undergo G2-prophase than rapid transit amplifying cells. In summary, a series of sequentially presenting markers could be used to indicate the progress of G2/M events in intestinal epithelial cells and other epithelial systems in vivo.

Cervical sympathetic block regulates early systemic inflammatory response in severe trauma patients.

BACKGROUND: This aim of this study was to investigate the effects of one-side cervical sympathetic block on early inflammatory response in severe trauma patients. MATERIAL AND METHODS: Thirty severe trauma patients with injury severity score (ISS) of 16 to 25 were randomly divided into treatment and control groups (n=15 each). Patients in the treatment group underwent a right-side stellate ganglion block (SGB) using 8 mL 0.75% ropivacaine for 4 times, with the first injection within 12 hr of admission and the other 3 injections were 12 hr, 24 hr and 48 hr later. The same procedures were performed for the control group except that normal saline was injected instead of ropivacaine. Blood was collected before injection and at 6 hr, 24 hr, and 72 hr after the first SGB for serum interleukin (IL)-1beta, IL-4, IL-6, IL-10 and TNF-alpha measurement. RESULTS: The concentrations of IL-1beta, IL-6, and TNF-alpha between 24 hr to 72 hr after SGB were all significantly lower than those in the control group (all P values <0.01). However, there was no significant difference in the concentrations of anti-inflammatory IL-4 and IL-10 between treatment and control groups. There was no obvious impact of SGB on breathing and circulation except for a slower heart rate 10 to 50 min after injection (P<0.01). CONCLUSIONS: SGB regulates early inflammatory response through inhibition of the proinflammatory cytokines IL-1beta, IL-6, and TNF-alpha during severe trauma. SGB has no impact on the levels of anti-inflammatory cytokines IL-4 and IL-10.

Different roles of TGF-ß in the multi-lineage differentiation of stem cells.

Stem cells are a population of cells that has infinite or long-term self-renewal ability and can produce various kinds of descendent cells. Transforming growth factor ß (TGF-ß) family is a superfamily of growth factors, including TGF-ß1, TGF-ß2 and TGF-ß3, bone morphogenetic proteins, activin/inhibin, and some other cytokines such as nodal, which plays very important roles in regulating a wide variety of biological processes, such as cell growth, differentiation, cell death. TGF-ß, a pleiotropic cytokine, has been proved to be differentially involved in the regulation of multi-lineage differentiation of stem cells, through the Smad pathway, non-Smad pathways including mitogen-activated protein kinase pathways, phosphatidylinositol-3-kinase/AKT pathways and Rho-like GTPase signaling pathways, and their cross-talks. For instance, it is generally known that TGF-ß promotes the differentiation of stem cells into smooth muscle cells, immature cardiomyocytes, chondrocytes, neurocytes, hepatic stellate cells, Th17 cells, and dendritic cells. However, TGF-ß inhibits the differentiation of stem cells into myotubes, adipocytes, endothelial cells, and natural killer cells. Additionally, TGF-ß can provide competence for early stages of osteoblastic differentiation, but at late stages TGF-ß acts as an inhibitor. The three mammalian isoforms (TGF-ß1, 2 and 3) have distinct but overlapping effects on hematopoiesis. Understanding the mechanisms underlying the regulatory effect of TGF-ß in the stem cell multi-lineage differentiation is of importance in stem cell biology, and will facilitate both basic research and clinical applications of stem cells. In this article, we discuss the current status and progress in our understanding of different mechanisms by which TGF-ß controls multi-lineage differentiation of stem cells.

Suppression of CX43 expression by miR-20a in the progression of human prostate cancer.

The aberrant expression of microRNAs (miRNAs) has been found in various types of cancer. The present study found miR-20a to be significantly upregulated in prostate cancer compared with normal prostate tissues. The proliferation and colony formation assays revealed that the downregulation of miR-20a by miR-20a inhibitor suppresses the proliferation of MDA-PCa-2b cells in vitro and also inhibits tumor growth in vivo. Furthermore, a gap junction protein, α 1 (CX43), was identified as a direct target gene of miR-20a. The upregulation of CX43 was detected in MDA-PCa-2b cells after treatment with miR-20a inhibitor both in vitro and in vivo. In conclusion, the findings show that miR-20a significantly contributes to the progression of prostate cancer by targeting CX43.

Steroid receptor coactivator-3 differentially regulates the inflammatory response in peritoneal macrophages.

Steroid receptor coactivator-3 (SRC-3) is a transcriptional coactivator that plays an important role in the regulation of cytokine mRNA translation. In the present study, SCR-3 gene knockout mice were used to study the effects of SCR-3 on the regulation of the inflammatory response in peritoneal macrophages induced by lipopolysaccharides (LPS). Peritoneal macrophages (PMs) of SRC-3-/- mice showed a decrease in the release of TNF-α, IL-1ß and IL-6, and an increase in the release of IL-10. Furthermore, results of RT-PCR also showed that levels of TNF-α, IL-1ß and IL-6 mRNA expression were significantly lower, while the level of IL-10 mRNA expression was higher in the SRC-3-/- mice, compared to those of wild-type mice, following treatment with LPS (p < 0.01). In addition, western blotting revealed that: i) the extent of reduction of the glucocorticoid receptor in PMs from SRC-3-/- mice was significantly lower than that in wild-type mice (p < 0.01); ii) the extent of increase of AP-1 in PMS from SRC-3-/- mice was significantly lower than that in wild-type mice (p < 0.01); iii) the extent of increase of NF-κB p65 in PMs from SRC-3-/- mice was significantly higher than that in wild-type mice (p < 0.01). Collectively, our studies revealed that SRC-3 may play a key role in the maintenance of innate immunity. Furthermore, absence of the SRC-3 protein may result in the partial loss of inflammation and phagocytosis barrier function, including suppression of LPS-induced transcriptional activity, release of TNF-α, IL-1ß and IL-6, and obstruction of the function of phagocytes and elimination of bacteria, as well as their production.

Effects of SCR-3 on the immunosuppression accompanied with the systemic inflammatory response syndrome.

Steroid receptor coactivator-3 (SRC-3) is a multifunctional protein that plays an important role in mammary gland growth, development, and tumorigenesis. In this study, SCR-3 gene knockout mice were used to study the effects of SCR-3 on the immunosuppression accompanied with systemic inflammatory response syndrome (SIRS). Bacterial clearance assay was performed by blood culture and frozen sections, and the results showed that the absence of SCR-3 protein serious damaged the innate immune system and the body's ability to inactivate or phagocytosis of bacteria was significantly decreased, and the absence of SCR-3 protein also weakened phagocytes' ability to degrade bacteria and their metabolites. Furthermore, animal model of inflammatory reaction was established and the immune function was determined, and the results revealed that SRC-3 protein may play an important role in maintenance of T-cells' immune function, and severe T-cell immune function disorder would be resulted once SRC-3 protein is missing. In addition, the results of our study showed the steady-state of lymphocyte subsets was destroyed after SIRS, leading the suppression of cellular immune function, and the absence of SCR-3 protein may aggravate the suppression of T-lymphocyte function. Therefore, the present study demonstrated that the absence of SCR-3 protein would aggravate immunosuppression. In addition, SRC-3 protein is a significant regulator of infection and inflammation, and SRC-3 protein play an essential role in the development of immunosuppression accompanied with SIRS.

Bone marrow mesenchymal stem cells can be mobilized into peripheral blood by G-CSF in vivo and integrate into traumatically injured cerebral tissue.

The efficacy of granulocyte colony-stimulating factor (G-CSF) in mobilizing mesenchymal stem cells (MSCs) into peripheral blood (PB) and the ability of PB-MSCs incorporated into injured brain were tested. Colony forming, cell phenotype and differentiation potential of mouse MSCs mobilized by G-CSF (40 µg/kg) were evaluated. Mortality and pathological changes in mice with serious craniocerebral trauma plus G-CSF treatment (40 µg/kg) were investigated. Bone marrow (BM) cells derived from GFP mice were fractionated into MSCs, hematopoietic stem cells (HSCs), and non-MSC/HSCs using magnetic beads and adherent culture. The resultant cell populations were transplanted into injured mice. The in vivo integration and differentiation of the transplanted cells were detected immunocytochemically. The expression of SDF-1 in injured area of brain was tested by Western blot. G-CSF was able to mobilize MSCs into PB (fourfold increase). PB-MSCs possessed similar characteristics as BM-MSCs in terms of colony formation, the expression pattern of CD73, 44, 90, 106, 31 and 45, and multipotential of differentiation. Accumulative total mice mortality was lower in TG group (5/14) than that in T group (7/14). It was MSCs, not HSCs or non-MSC/HSC cells integrated into the damaged cerebral tissue and differentiated into cells expressing neural markers. Increased SDF-1 expression in injured area of brain was confirmed, which could facilitate the homing of MSCs to brain. G-CSF can mobilize MSCs into PB and MSCs in PB can integrate into injured cerebral tissue and transdifferentiated into neural cells and may benefit the repair of trauma.

Experimental research on the management of combined radiation-burn injury in China.

Combined radiation-burn injury can occur in people exposed to nuclear explosions, nuclear accidents or radiological terrorist attacks. Using different combined radiation-burn injury animal models, the pathological mechanisms underlying combined radiation-burn injury and effective medical countermeasures have been explored for several years in China, mainly at our institute. Targeting key features of combined radiation-burn injury, several countermeasures have been developed. Fluid transfusion and the calcium antagonist verapamil can prevent early shock and improve myocardial function after combined radiation-burn injury. Recombinant human interleukin 4 (rhIL-4) is able to effectively reduce bacterial infection and increase intestinal immunological ability. Chitosan-wrapped human defensin 5 (HD5) and glucagon-like peptide 2 (GLP-2) nanoparticles can increase the average survival time of animals with severe combined radiation-burn injury. After treatment by cervical sympathetic ganglia block (SB), hematopoietic function is promoted and the release of inflammatory cytokines is suppressed. The optimal time for escharectomy and allo-skin grafting is 24 h after injury. Transfusion of irradiated (20 Gy) or stored (4°C, 7 days) blood improves the survival of allo-skin grafting and allo-bone marrow cells. In conclusion, as our understanding of the mechanisms of combined radiation-burn injury has progressed, new countermeasures have been developed for its treatment. Because of the complexity of its pathology and the difficulty in clinical management, further efforts are needed to improve the treatment of this kind of injury.

Reversible immortalization of rat pancreatic ß cells with a novel immortalizing and tamoxifen-mediated self-recombination tricistronic vector.

Although the strategy of "Cre/LoxP-based reversible immortalization" holds great promise to overcome the cellular senescence of primary cell cultures for their further use, a secondary gene transfer for Cre expression is usually utilized to trigger the excision of the immortalizing genes in a large number of cells, thus presenting a formidable hurdle for large-scale application. We modified the strategy by utilizing a tricistronic retroviral vector pLCRSTP, in which Cre-ER, simian virus 40 large T antigen (SV40LTAg) oncogene, and a reporter gene were flanked by the same pair of LoxA sites. Five immortalized rat pancreatic ß cell clones transduced with pLCRSTP, and six immortalized rat pancreatic ß cell clones co-transduced with pLCRSTP and another vector encoding the human telomerase reverse transcriptase (hTERT) gene, were obtained, respectively. The Cre-ER protein could be induced to translocate from the cytoplasm to the nucleus by 4-hydroxytamoxifen to make SV40LTAg, hTERT and the Cre-ER gene itself excise without a secondary gene transfer. Our studies suggest that this system is useful to expand rat ß cells and may allow for large-scale production due to its simpler manipulation.

Protective effect of atorvastatin on radiation-induced vascular endothelial cell injury in vitro.

Vascular endothelial cells are very sensitive to ionizing radiation, and it is important to develop effective prevent agents and measures in radiation exposure protection. In the present study, the protective effects of atorvastatin on irradiated human umbilical vein endothelial cells (HUVEC) and the possible mechanisms were explored. Cultured HUVEC were treated by atorvastatin at a final concentration of 10 µ mol/ml for 10 minutes, and then irradiated at a dose of 2 Gy or 25 Gy. Twenty-four hours after irradiation, apoptosis of HUVEC was monitored by flow cytometry, and the expression of thrombomodulin (TM) and protein C activation in HUVEC was respectively assessed by flow cytometry and spectrophotometry. After treatment with atorvastatin for 24 h, the rate of cell apoptosis decreased by 6% and 16% in cells irradiated with 2 Gy and 25 Gy, respectively. TM expression increased by 77%, 59%, and 61% in untreated cells, 2 Gy irradiation-treated cells, and 25 Gy irradiation-treated cells, respectively. The protein C levels in 2 Gy and 25 Gy irradiation-treated cells were reduced by 23% and 34% when compared with untreated cells, but up-regulated by 79% and 76% when compared with cells which were irradiated and treated with atorvastatin. In conclusion, these data indicate that atorvastatin exerts protective effects on irradiated HUVEC by reducing apoptosis by up-regulating TM expression and enhancing protein C activation in irradiated HUVEC.

Effect of hBD2 genetically modified dermal multipotent stem cells on repair of infected irradiated wounds.

Deficiencies in repair cells and infection are two of the main factors that can hinder the process of wound healing. In the present study, we investigated the ability of human beta-defensin-2 (hBD2) genetically modified dermal multipotent stem cells (dMSCs) to accelerate the healing irradiated wounds complicated by infections. An hBD2 adenovirus expression vector (Adv-hBD2) was firstly constructed and used to infect dMSCs. The antibacterial activity of the supernatant was determined by Kirby-Bauer method and macrodilution broth assay. Time to complete wound healing, residual percentage of wound area, and the number of bacteria under the scar were measured to assess the effects of Adv-hBD2-infected dMSC transplantation on the healing of irradiated wounds complicated by Pseudomonas aeruginosa infection. Results showed that the supernatant from Adv-hBD2-infected dMSCs had obvious antibacterial effects. Transplantation of Adv-hBD2-infected dMSCs killed bacteria in the wound. The complete wound healing time was 19.8 ± 0.45 days, which was significantly shorter than in the control groups (P < 0.05). From 14 days after transplantation, the residual wound area was smaller in the experimental group than in the control groups (P < 0.05). In conclusion, we found that transplantation of hBD2 genetically modified dMSCs accelerated the healing of wounds complicated by P. aeruginosa infection in whole body irradiated rats.

Human bone marrow mesenchymal stem cells expressing SDF-1 promote hematopoietic stem cell function of human mobilised peripheral blood CD34+ cells in vivo and in vitro.

PURPOSE: There is mounting evidence demonstrating that stromal cell derived factor-1 (SDF-1) plays an important role in homing of hematopoietic progenitor cells to bone marrow. This study was aimed to assess whether bone marrow mesenchymal stem cells overexpressing exogenous SDF-1 could synergistically promote the homing of CD34(+) (Cluster of Differentiation [CD]) cells to bone marrow of lethally irradiated severe combined immunodeficiency (SCID) mice. METHODS: Human SDF-1 complementary Deoxyribonucleic acid (cDNA) was transfected into bone marrow-derived mesenchymal stem cells with recombinant lentiviral vector. The expression of SDF-1 was detected by real-time Polymerase Chain Reaction (PCR) and Enzyme-Linked Immunosorbent Assay (ELISA), and the ex vivo chemotaxis function on CD34(+) cells was measured by coculture system and Transwell system. SDF-1 gene-modified mesenchymal stem cell (MSC) and CD34(+) cells were infused into lethally irradiated SCID mice and the hematopoietic reconstitution in the recipient mice was examined. RESULTS: Messenger ribonucleic acid (mRNA) and protein of SDF-1 in infected MSC were significantly higher than that of the non-infected control MSC (p < 0.05). The infected MSC have significant chemotaxis effect on CD34(+) cells in vitro and promote hematopoietic reconstitution after CD34(+) cell transplantation in vivo. CONCLUSION: MSC with high-level expression of SDF-1 can synergistically promote hematopoietic reconstitution after CD34(+) cell transplantation in lethally irradiated SCID mice.

The interaction between interferon-induced protein with tetratricopeptide repeats-1 and eukaryotic elongation factor-1A.

It has been shown previously that in mammalian cells, interferon-induced protein with tetratricopeptide repeats-1(IFIT1) is rapidly synthesized in response to viral infection, functions as an inhibitor of translation by binding to the eukaryotic initiation factor-3, and consequently assigns resistive activity against viral invasion to cells. It has also been reported that IFIT1 is rapidly produced in response to other cell stress agents with no direct relation to virus such as bacterial lipopolysaccharide and interleukin-1, but its function under these non-viral infection cell stress conditions has yet to be elucidated. Here, we demonstrate an interaction between IFIT1 and eukaryotic elongation factor-1A (eEF1A) both in vitro, using recombinant proteins as bait in pull-down assays, and in vivo, using laser confocal microscopy and immunoprecipitation. In addition, we report the initial determination of the domain of IFIT1 that mediates this interaction. We also display that both IFIT1 and eEF1A protein levels are rapidly elevated, prolonged in tumor necrosis factor alpha pre-treated Raw264.7 cells, and most of those cells are induced to death by the end of investigations. Our results imply that under some stressful stimulations IFIT1 may participate in cell death pathways by interaction with eEF1A.

CXCR4 gene transfer enhances the distribution of dermal multipotent stem cells to bone marrow in sublethally irradiated rats.

Our previous study indicated that systemically transplanted dermal multipotent cells (DMCs) were recruited more frequently to bone morrow (BM) of rats with sublethal irradiation than that of normal rats, and the interactions between stromal-derived factor (SDF-1) and its receptor (CXC chemokine receptor 4, CXCR4) played an important role in this process. In the present study, we aimed to investigate whether CXCR4 gene transfer could promote the distribution of DMCs into irradiated BM and accelerate its function recovery. Firstly, adenovirus vector of CXCR4 (Adv-CXCR4) and green fluorescent protein (Adv-GFP) were constructed. Then male DMCs infected by Adv-CXCR4 (group A), or infected by Adv-GFP (group B), and non-infected DMCs (group C) were transplanted into irradiated female rats, and real-time polymerase chain reaction for the sex-determining region of Y chromosome was employed to determined the amount of DMCs in BM. The functional recovery of BM was examined by hematopoietic progenitor colonies assay. The results showed that the amount of DMCs in BM of group A was greater than that in group B and group C from day 5 after injury (P < 0.05), and the amount of CFU-F, CFU-E and CFU-GM were greater than that in group B and group C from day 14 after injury (P < 0.05). These findings suggest that DMCs infected by Adv-CXCR4 distributed more frequently to the bone marrow of sublethally irradiated rats and could accelerate hematopoiesis function recovery.

[Exogenous gene expression in vitro and in vivo in bone marrow mesenchymal stem cells modified by hPDGF-A and hBD(2)].

The objective of this study was to investigate the expression of exogenous hPDGF-A and hBD(2) in gene-modified bone marrow mesenchymal stem cells (BM-MSCs) in vitro and in vivo. Recombinant adenovirus vector expressing hPDGF-A/hBD(2) genes was constructed and packaged into virion. Primary isolated and cultured BM-MSCs were transfected by using hPDGF-A hBD(2), then the expressions of exogenous hPDGF-A/hBD(2) were detected by immunocytochemical staining in vitro. The conditioned medium (serum-free cultured supernatant of BM-MSCs transfected with recombinant adenovirus) collected from gene-modified BM-MSCs was applied to scratch wound on monolayer cells of multipotential cell line 10T1/2 in order to confirm the stimulative effect of hPDGF-A on cell migration. Gene-modified BM-MSCs were topically transplanted on wound of rats with radiation and skin excision combined injury. The distribution of BM-MSCs and expression of hPDGF-A/hBD(2) on the wound was observed by fluorescent microscopy and immunohistochemical staining respectively. The results indicated that the rat BM-MSCs transfected with recombinant adenovirus could express the EGFP in vitro. The immunofluorescent cytochemistry assay showed that the gene-modified BM-MSCs expressed the hPDGF-A and hBD(2). The scratch test confirmed that the percentage of healing area of wound in cultured supernatant group of gene-modified BM-MSCs was significant higher than that in control group on 8, 12, 24 and 48 hours (p < 0.05). The fluorescence microscopy of exogenous gene-modified BM-MSCs transplanted on wound revealed that the gene-modified BM-MSCs could higher express exogenous genes of EGFP at least within 2 weeks. The immunohistochemistry staining of wound indicated that the expression of exogenous genes began from day 3, reached to peak on day 7, and still visible on day 21 even though the expression became weak because of the possible dilution of the exogenous genes during cell division. It is concluded that efficient expression of exogenous hPDGF-A/hBD(2) in gene-modified BM-MSCs are demonstrated both in vitro and in vivo, which suggests that the molecular mechanism underlying chronic wound-healing accelerated by the strategy combining cell therapy with gene therapy.

Recruitment of transplanted dermal multipotent stem cells to sites of injury in rats with combined radiation and wound injury by interaction of SDF-1 and CXCR4.

Systemic transplantation of dermal multipotent stem cells has been shown to accelerate both hematopoietic recovery and wound healing in rats with combined radiation and wound injury. In the present study, we explored the mechanisms governing the recruitment of dermal multipotent stem cells to the sites of injury in rats with combined injury. Male dermal multipotent stem cells were transplanted into female rats, and using quantitative real-time PCR for the sex-determining region of Y chromosome, it was found that the amounts of dermal multipotent stem cells in irradiated bone marrow and wounded skin were far greater than those in normal bone marrow and skin (P < 0.01). However, incubation of dermal multipotent stem cells with AMD3100 before transplantation, which specifically blocks binding of stromal cell-derived factor 1 (SDF-1) to its receptor CXCR4, diminished the recruitment of dermal multipotent stem cells to the irradiated bone marrow and wounded skin by 58 +/- 4% and 60 +/- 4%, respectively (P < 0.05). In addition, it was confirmed that the expression of SDF-1 in irradiated bone marrow and wounded skin was up-regulated compared to that in their normal counterparts, and in vitro analysis revealed that irradiated bone marrow and wounded skin extracts had a strong chemotactic effect on dermal multipotent stem cells but that the effect decreased significantly when dermal multipotent stem cells were preincubated with AMD3100 (P < 0.05). These data suggest that transplanted dermal multipotent stem cells were recruited more frequently to the irradiated bone marrow and wounded skin than normal bone marrow and skin and that the interactions of SDF-1 and CXCR4 played a crucial role in this process.

Effects of peritoneal lavage fluid from radiation or/and burn injured rats on the growth of hematopoietic progenitor cells.

PURPOSE: To evaluate the effects of peritoneal lavage fluids from radiation injury, burn injury and combined radiation-burn injury on the growth of hematopoietic progenitor cells (HPC). MATERIALS AND METHODS: Rats were divided into four groups: A radiation group (RG), a burn group (BG), a combined radiation-burn group (CRBG) and normal control group (NG). RG and CRBG rats were irradiated with 12 Gy, and burns of 30% total body surface area were generated in group BG and group CRBG. Peritoneal lavage fluids were collected and tested for their effects on the growth of erythrocyte progenitor cells or granulocyte-macrophage progenitor cells of BALB/c mice in vitro. RESULTS: The numbers of colony forming units-erythroid (CFU-E), burst forming units-erythroid (BFU-E) and colony-forming units-granulocyte-macrophage (CFU-GM) formed after treatment with lavage fluids from BG or CRBG were significantly higher than those from NG. However, fewer CFU-E, BFU-E or CFU-GM colonies were found after treatment with lavage fluid from the RG. In lavage fluid from BG and CRBG, the concentration of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor alpha (TNFalpha) was increased in comparison to NG and RG. Treatment with these cytokines had similar promoting effects on the growth of hematopoietic colonies and neutralizing antibodies inhibited these effects significantly. CONCLUSIONS: Burns increase the responsiveness of the system and help the proliferation of hematipoietic progenitor cells, while radiation decreases all these responses relative to both the controls and the burn plus radiation group.

[Experimental study on human bone marrow mesenchymal stem cells transfected by SDF-1 cDNA].

This study was aimed to investigate the expression of SDF-1 mRNA in SDF-1 cDNA-modified human bone marrow mesenchymal stem cells (hBMSCs) before and after transfection. The hBMSCs were isolated, cultured and identified, the SDF-1-pIRES2-EGFP eukaryotic expressing vector was constructed, and then the hBMSCs were transfected with the vector encapsulated by lipofectamine 2000. The transfection efficiency was measured by observing the expression of green fluorescence protein and detecting the mRNA by RT-PCR. The results indicated that the expression of SDF-1 mRNA increased by about 20% after hBMSCs were transfected instantaneously by SDF-1-pIRES2-EGFP. It is concluded that SDF-1 cDNA eukaryotic expression vector can be instantly transfected into hBMSCs by lipofectamine 2000, but the efficiency was too low to obtain enough steady transferred hBMSCs. Other procedures should be trialed to improve the transfection efficiency.

[Influence of cervical sympathetic nerve block on blood flow volume and barrier function of intestinal mucosa after combined radiation and burn injury in rat].

OBJECTIVE: To investigate the influence of cervical sympathetic nerve block (SB) on blood flow volume and barrier function of intestinal mucosa after combined radiation and burn injury in rat. METHODS: SD rats were divided into three groups: control (n = 18), combined injury group (n = 100, rats with Co gamma ray body irradiation with a dose of 5 Gy plus 15% TBSA full-thickness burn injury), and combined injury with SB treatment (n = 100, with the same dose of gamma-ray irradiation and burn injury, treated with SB). Twenty rats were sacrificed on 0, 1, 5, 7 days after combined injuries for various observations. SB was conducted with injection of ropivhydrochloride into the neck bilaterally for the SB group, and same amount of normal saline was injected instead in the combined injury group. Blood flow volume, changes in villus height and crypt depth in jejunum, Na(+)-K+ ATPase activity, permeability of small intestine were measured at different time-points. RESULTS: The blood flow volume in small intestinal mucosal on 1 post-injury days (PID) [(0.29 +/- 0.07) ml x min(-1) x g(-1)] were obviously decreased than that in normal controls [(1.26 +/- 0.23) ml x min(-1) x g(-1), P < 0.01 ], with serious destruction of pit cells, decrease in intestinal mucosal Na(+)-K+ ATPase activity, and increase in intestinal mucosal permeability. Compared with combined injury group, the blood flow volume was [(0.82 +/- 0.11) ml x min(-1) x g(-1) 1 day after combined injury, P < 0.01], and the Na(+)-K+ ATPase activity was obviously increased, and the permeability of small intestine was ameliorated. CONCLUSION: SB can increase blood flow volume of rat small intestine after combined radiation and burn injury, promote the repair of intestinal epithelium and improve the barrier function of the intestinal wall.