Apoptosis-resistant megakaryocytes produce large and hyperreactive platelets in response to radiation injury.

BACKGROUND: The essential roles of platelets in thrombosis have been well recognized. Unexpectedly, thrombosis is prevalent during thrombocytopenia induced by cytotoxicity of biological, physical and chemical origins, which could be suffered by military personnel and civilians during chemical, biological, radioactive, and nuclear events. Especially, thrombosis is considered a major cause of mortality from radiation injury-induced thrombocytopenia, while the underlying pathogenic mechanism remains elusive. METHODS: A mouse model of radiation injury-induced thrombocytopenia was built by exposing mice to a sublethal dose of ionizing radiation (IR). The phenotypic and functional changes of platelets and megakaryocytes (MKs) were determined by a comprehensive set of in vitro and in vivo assays, including flow cytometry, flow chamber, histopathology, Western blotting, and chromatin immunoprecipitation, in combination with transcriptomic analysis. The molecular mechanism was investigated both in vitro and in vivo, and was consolidated using MK-specific knockout mice. The translational potential was evaluated using a human MK cell line and several pharmacological inhibitors. RESULTS: In contrast to primitive MKs, mature MKs (mMKs) are intrinsically programmed to be apoptosis-resistant through reprogramming the Bcl-xL-BAX/BAK axis. Interestingly, mMKs undergo minority mitochondrial outer membrane permeabilization (MOMP) post IR, resulting in the activation of the cyclic GMP-AMP synthase-stimulator of IFN genes (cGAS-STING) pathway via the release of mitochondrial DNA. The subsequent interferon-ß (IFN-ß) response in mMKs upregulates a GTPase guanylate-binding protein 2 (GBP2) to produce large and hyperreactive platelets that favor thrombosis. Further, we unmask that autophagy restrains minority MOMP in mMKs post IR. CONCLUSIONS: Our study identifies that megakaryocytic mitochondria-cGAS/STING-IFN-ß-GBP2 axis serves as a fundamental checkpoint that instructs the size and function of platelets upon radiation injury and can be harnessed to treat platelet pathologies.

Isolation and characterization of two kinds of stem cells from the same human skin back sample with therapeutic potential in spinal cord injury.

BACKGROUNDS AND OBJECTIVE: Spinal cord injury remains to be a challenge to clinicians and it is attractive to employ autologous adult stem cell transplantation in its treatment, however, how to harvest cells with therapeutic potential easily and how to get enough number of cells for transplantation are challenging issues. In the present study, we aimed to isolate skin-derived precursors (SKPs) and dermal multipotent stem cells (dMSCs) simultaneously from single human skin samples from patients with paraplegia. METHODS: Dissociated cells were initially generated from the dermal layer of skin samples from patients with paraplegia and cultured in SKPs proliferation medium. Four hours later, many cells adhered to the base of the flask. The suspended cells were then transferred to another flask for further culture as SKPs, while the adherent cells were cultured in dMSCs proliferation medium. Twenty-four hours later, the adherent cells were harvested and single-cell colonies were generated using serial dilution method. [(3)H]thymidine incorporation assay, microchemotaxis Transwell chambers assay, RT-PCR and fluorescent immunocytochemistry were employed to examine the characterizations of the isolated cells. RESULTS: SKPs and dMSCs were isolated simultaneously from a single skin sample. SKPs and dMSCs differed in several respects, including in terms of intermediate protein expression, proliferation capacities, and differentiation tendencies towards mesodermal and neural progenies. However, both SKPs and dMSCs showed high rates of differentiation into neurons and Schwann cells under appropriate inducing conditions. dMSCs isolated by this method showed no overt differences from dMSCs isolated by routine methods. CONCLUSIONS: Two kinds of stem cells, namely SKPs and dMSCs, can be isolated simultaneously from individual human skin sample from paraplegia patients. Both of them show ability to differentiate into neural cells under proper inducing conditions, indicating their potential for the treatment of spinal cord injury patients by autologous cell transplantation.

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.

Current state and future perspectives of trauma care system in mainland China.

OBJECTIVE: To investigate the current state of trauma care in mainland China, and to propose possible future suggestions for the development of the trauma care system in mainland China. METHOD: An extensive Medline/PubMed search on the topic of trauma care or trauma care system was conducted. Publications in Chinese that could best describe the state of trauma care in China were also included. In addition, two meetings were held by Group for Trauma Emergency Care and Multiple Injuries, Trauma Society of Chinese Medical Association to discuss the development and perspectives of trauma care system in mainland China. Important conclusions from the two meetings were included in this publication. RESULTS: Trauma has become an increasing public health problem in mainland China in association with the rapid growth of the economy over the past 30 years. Although great progress has been made in regards to the care of the injured, there is still no government agency dedicated to deal with trauma-related issues, or a national trauma care system operating on the Chinese mainland. Various trauma prevention measures have been taken, but with little effect. Funds contributed to trauma-related research has increased in recent years and promoted rapid development in this field, but further improvement in research is needed. However, many groups such as the Trauma Society of the Chinese Medical Association have continued to explore mechanisms for the treatment of trauma patients and have developed various types of regional trauma care systems, resulting in improved trauma care and a better outcome for the injured. CONCLUSIONS: Although great progress has been made in trauma care in mainland China, there are many failings. To improve trauma care in China, the establishment of a sophisticated trauma system and various enhancements on trauma prevention are urgently required.

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.

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.

Protective effect of an extract from Periplaneta americana on hematopoiesis in irradiated rats.

PURPOSE: To investigate the protective effect of W(11)-a(12), an extract from Periplaneta americana, on hematopoiesis in irradiated rats. MATERIALS AND METHODS: Wistar rats receiving total body irradiation of (60)Co gamma-rays alone or with combined radiation and skin wound injury were used in this study. W(11)-a(12) was applied either topically into the skin wounds or systemically by intraperitoneal injection. The numbers of white blood cells in peripheral blood, the nucleated cells and the colony-forming unit of granulocyte/macrophage progenitors (CFU-GM) in bone marrow were measured, respectively. RESULTS: Topical application of W(11)-a(12) into skin wounds in rats with combined 6 Gy total body irradiation and skin wound injury could increase the neutrophils and macrophages in the wounded area and the nucleated cells in bone marrow at 24 h and 48 h, while the peripheral white blood cells did not show significant change. However, in rats with 4 Gy total body irradiation alone, the peripheral white blood cells, bone marrow nucleated cells and the number of colony-forming unit of granulocyte-macrophage progenitors were all significantly higher in the treatment groups by intraperitoneal injection of W(11)-a(12) than those in the control groups by injection of normal saline at days 3 and days 5 after radiation. CONCLUSIONS: W(11)-a(12) showed a protective effect on hematopoiesis after total body irradiation and could increase the inflammatory cells in wounded tissues at the initiation stage after irradiation, which will benefit the management of combined radiation and skin wound injury.

[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.

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.

[Studies on the treatment of combined radiation-burn injury].

Combined radiation-burn injuries mainly occur under the circumstances of nuclear explosion, nuclear accident, nuclear terrorism, depleted uranium attack, as well as secondary injuries following attack on nuclear installation. Combination of burn and radiation injuries bring along more serious whole body damage, more complicated pathological mechanism and much more difficult management. Research progress on the pathological mechanism and medical management of several key links of combined injury were discussed in this paper. (1) Enhancement of early first aid and prevention of early death of wounded. (2) Damage and restoration of hemopoietic function. (3) Disturbance of immune function and prevention and treatment of infection (mainly on the intestinal mucosa immunity and enterological infection). (4) Management of burn wound. (5) The role of several important measures in the comprehensive treatment.

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.

Autoantibodies to the high-affinity IgE receptor in patients with asthma.

Autoimmune diseases have been implicated as a cause of intrinsic asthma; however, there is little data on the role of autoimmunity in the pathogenesis of asthma. The purpose of this study was to investigate circulating autoantibodies against the high-affinity IgE receptor Fc(epsilon)RI in patients with asthma. Seventy-eight patients with asthma and 32 healthy individuals as control subjects were included. All subjects were tested with basophil histamine releasing assay and immunoblotting to assess for the potential presence of receptor Fc(epsilon)RI autoantibodies. Of the 78 asthma patients total subjects, 25 (32.1%) had a positive by basophil histamine releasing assay and 23 (29.5%) by immunoblotting. Both of them were significant higher than the positive rate, 9.4% (p < 0.05) and 9.4% (p < 0.05), respectively. Our data demonstrated that aberrant autoantibodies against the high-affinity IgE receptor Fc(epsilon)RI were found in some patients with asthma implies that the autoimmunity may be one factor in intrinsic asthma pathogenesis.

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.

Effects of serum from rats with combined radiation-burn injury on the growth of hematopoietic progenitor cells.

BACKGROUND: This study aims to observe the effects of blood serum from rats with radiation injury, burn injury, and combined radiation-burn injury on the growth of hematopoietic progenitor cells and to explore the possible mechanisms. METHODS: Serum from rats with radiation injury, burn injury, and combined radiation-burn injury were collected at 3 hours, 12 hours, 24 hours, 48 hours, 72 hours, and 96 hours after injury and then was added to the culture medium to see its effect on the growth of hematopoietic progenitor cells (HPCs) at a final protein concentration of 10 microg/mL. Radioimmunoassay and enzyme-linked immunosorbent assay were employed to measure the level of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 in each group, and the effect of TNF-alpha and IL-6 on the growth of HPC was also observed. RESULTS: The number of HPCs colonies formed after addition of the serum from rats with burn or combined radiation-burn injuries was significantly higher than that from normal rats at 3 hours, 12 hours, 24 hours, 48 hours, 72 hours, and 96 hours after injury and reached its peak value at 24 hours after injury. However, fewer HPCs colonies were found after the addition of the serum from irradiated rats. At the same time, the levels of TNF-alpha and IL-6 in the serum of burn group and combined radiation-burn injury group were significantly higher than that of normal group, and much higher than that of the irradiation injury group (p < 0.01). Also, TNF-alpha and IL-6 demonstrated promoting effect on the growth of HPC. CONCLUSION: Serum from rats with burn injury and combined radiation-burn injury stimulates the growth of HPCs, while serum from irradiated rats shows inhibitory effects on the growth of HPCs. These effects may lie in the different level of TNF-alpha and IL-6 in the serum of each group.

Crucial role of SDF-1/CXCR4 interaction in the recruitment of transplanted dermal multipotent cells to sublethally irradiated bone marrow.

Our previous study indicated that dermal multipotent cells (DMCs) could engraft into bone morrow (BM) of rats with sublethal irradiation and promote hematopoietic recovery after being transplanted systemically, but the mechanisms determining the recruitment of DMCs to the irradiation injured BM remain unclear. In the present study, we investigated the role of stromal cellderived factor-1 (SDF-1)/CXCR4 interaction in this process. Male DMCs were isolated and transplanted into female rats systemically, and by employing quantitative real-time TaqMan polymerase chain reaction for the sex-determining region of Y chromosome, it was found that the amount of DMCs in BM of rats with sublethal irradiation was about 3 times more than that of normal rats (P < 0.01). Incubation of DMCs with AMD3100 before transplantation, which specifically blocks binding of SDF-1 to its endogenous receptor CXCR4, diminished recruitment of DMCs to the injured BM by 57.2 +/- 5.5% (P < 0.05). In addition, it was confirmed that the expression of SDF-1 in injured BM was up-regulated when compared with that in normal BM, and in vitro analysis revealed that BM extracts from irradiated rats had a strong chemotactic effect on DMCs, which decreased significantly when DMCs were pre-incubated with AMD3100 (P < 0.05). These data suggest that transplanted DMCs were recruited more frequently to irradiation-injured BM than normal BM and the interactions of SDF-1/CXCR4 played an important role in this process.

Recent advances in the pathological basis and experimental management of impaired wound healing due to total-body irradiation.

Combined radiation and wound injury (CRWI) occurs in nuclear attacks and severe nuclear accidents. The possibility of radiological terrorist attack further emphasizes the significance of studies on CRWI. This kind of skin wound is very complex and difficult to heal since a high dose of total-body irradiation could delay wound healing and cause bone marrow dysplasia. Since the 1990s, the study of impaired wound healing due to total-body irradiation (TBI) has been emphasized in China. In this article, the pathological basis of the wound-healing process after TBI are reviewed and experimental management using traditional agents, growth factors, stem cells, and allo-skin transplantation in this kind of healing-impaired wound is also discussed.

Impaired wound healing after local soft x-ray irradiation in rat skin: time course study of pathology, proliferation, cell cycle, and apoptosis.

BACKGROUND: Soft x-ray irradiation is usually used to treat skin-related disease in the clinic, but its effect on wound healing has not been well elucidated. The purpose of our study was to develop a wound-healing model of local soft x-ray irradiation on rats and to clarify the possible cellular mechanisms through which radiation may influence healing. METHODS: Full-thickness, 2-cm-diameter, dorsal cutaneous tissue was excised after local irradiation in rats. The dose-effect curve was recorded, and five animals irradiated with doses of 521 rad were killed at postwound days 3, 6, 9, and 15 and five were healed for histologic examination (hematoxylin and eosin staining), cell proliferation (5-bromo-2'-deoxyuridine [BrdU] incorporation), apoptosis (and terminal deoxynucleotidyl transferase biotin-dUTP nick end-labeling [TUNEL] method), and the cell cycle (flow cytometry). RESULTS: Soft x-ray irradiation delayed wound-healing time with an S-like curve, and the wounds that received doses in excess of 700 rad failed to heal within 40 days. This dose-effect range is far below that of gamma and hard x-ray irradiation. Relative to control wounds, which contained prominent BrdU-positive labeling at days 3 through 9 and minimal TUNEL-positive labeling during the entire healing, the irradiated wounds had less BrdU-positive labeling and significant TUNEL-positive labeling at days 3 through 9 but more BrdU-positive labeling and similar TUNEL-positive labeling at day 15. Flow cytometry studies found a higher proportion of G0/G1 phase cells (days 3-9), a lower (days 3-9) then higher (days 13-22) proportion of S phase cells, and a persistent lower proportion of G2/M phase cells (during the entire healing process) in the irradiated wounds compared with the controls. CONCLUSION: Local soft x-ray irradiation could delay wound healing in a dose-dependent manner and shows a more effective biological effect than that of gamma and hard x-ray irradiation. Radiation-induced inactive cell proliferation, active cell apoptosis, and arrested cell cycle at days 3 through 9 may be one of the cellular mechanism responsible for delayed wound healing.

[Influence of macrophages on the expression of vascular endothelial growth factor receptor mRNA, homeobox B2 mRNA, and integrin alpha nu beta3 in vascular endothelial strain].

OBJECTIVE: To investigate the influence of macrophages on the expression of the vascular endothelial growth factor (VEGF) receptor (KDR) mRNA, homeobox B2 (HOXB2) mRNA, and integrin alpha nu beta3 in vitro in vascular endothelial strain. METHODS: Human umbilical vein cells (ECV304) were cultured in vitro and divided into 4 groups, i.e. (1) ECV304 group, (2) ECV304 + conA group [with conA (25 microg/ml in culture) added to ECV304], (3) ECV304 + U937 group (with 1 x 10(5)/ml of U937 cells added to 1 x 10(5)/ml ECV 304), (4) ECV304 + U937 + conA group [with 1 x 10(5)/ml of U937 cells and conA (25 microg/ml in culture)] groups. Forty-eight hours after culturing, the expression of integrin receptor alpha nu beta3 and the changes in the expression of KDR mRNA and HOXB2 mRNA in each group were determined by immunofluorescent technique and RT-PCR, respectively. RESULTS: The expression of integrin receptor alpha nu beta3, KDR mRNA, and HOXB2 mRNA in ECV304 group were 6.7 +/- 1.5, 0.633 +/- 0.012, and 0.674 +/- 0.004, respectively, while those in ECV304 + U937 + conA group (10.2 +/- 1.7, 0.879 +/- 0.003, 0.947 +/- 0.003) were obviously more upregulated when compared with those in ECV304 group (P < 0.01). No difference in the above indices was found between ECV304 and ECV304 + conA, ECV304 + U937 groups (P > 0.05). CONCLUSION: Macrophages activated by ConA can accelerate the proliferation, migration and adhesion to the basement membrane matrix of vascular endothelial cells through the influence on the expression of KDR mRNA, HOXB2 mRNA and integrin alpha nu beta3, and through this pathway the angiogenesis is modulated.