Single-Dose Administration of Recombinant Human Thrombopoietin Mitigates Total Body Irradiation-Induced Hematopoietic System Injury in Mice and Nonhuman Primates.

PURPOSE: Recombinant human thrombopoietin (rhTPO) has been evaluated as a therapeutic intervention for radiation-induced myelosuppression. However, the immunogenicity induced by a repeated-dosing strategy raises concerns about the therapeutic use of rhTPO. In this study, single-dose administration of rhTPO was evaluated for efficacy in the hematopoietic response and survival effect on mice and nonhuman primates exposed to total body irradiation (TBI). METHODS AND MATERIALS: Survival of lethally (9.0 Gy) irradiated C57BL/6J male mice was observed for 30 days after irradiation. Hematologic evaluations were performed on C57BL/6J male mice given a sublethal dose of radiation (6.5 Gy). Furthermore, in sublethally irradiated mice, we performed bone marrow (BM) histologic evaluation and evaluated BM-derived clonogenic activity. Next, the proportion and number of hematopoietic stem cells (HSCs) were analyzed. Competitive repopulation experiments were conducted to assess the multilineage engraftment of irradiated HSCs after BM transplantation. Flow cytometry was used to evaluate DNA damage, cell apoptosis, and cell cycle stage in HSCs after irradiation. Finally, we evaluated the efficacy of a single dose of rhTPO administered after 7 Gy TBI in male and female rhesus monkeys. RESULTS: A single administration of rhTPO 2 hours after irradiation significantly mitigated TBI-induced death in mice. rhTPO promoted multilineage hematopoietic recovery, increasing peripheral blood cell counts, BM cellularity, and BM colony-forming ability. rhTPO administration led to an accelerated recovery of BM HSC frequency and multilineage engraftment after transplantation. rhTPO treatment reduced radiation-induced DNA damage and apoptosis and promoted HSC proliferation after TBI. Notably, a single administration of rhTPO significantly promoted multilineage hematopoietic recovery and improved survival in nonhuman primates after TBI. CONCLUSIONS: These findings indicate that early intervention with a single administration of rhTPO may represent a promising and effective radiomitigative strategy for victims of radiation disasters.

Efficacy of tea polyphenols (TP 50) against radiation-induced hematopoietic and biochemical alterations in beagle dogs.

OBJECTIVE: To investigate the radioprotective effect of tea polyphenols (TP 50) against radiation-induced organ and tissue damage. METHODS: Beagle dogs were exposed to a single acute dose of whole-body γ-radiation (3 Gy) and orally administered TP 50 (80 or 240 mg·kg－1·d－1) for 28 consecutive days. A hemogram was obtained from experimental dogs every other day for 42 d. At the end of the experiment, enzyme activities of the antioxidants superoxide-dismutase andglutathione peroxidase, serum levels of inflamma- tory cytokines (tumor necrosis factor-α, interleukin-1ß, and interleukin-6), colony-forming units of bone marrow hematopoietic progenitor cells, andorgan coefficients were measured. RESULTS: Dogs exposed to γ-radiation alone exhibited typical hematopoietic syndrome. In contrast, irradiated dogs that received TP 50 exhibited an improved blood profile with reduced leucopenia, thrombocytopenia (platelet counts), and reticulocyte levels. TP 50 also significantly elevated levels of the endogenous antioxidant enzyme superoxide-dismutase, reduced the increased levels of serum cytokine in response to radiation-induced toxicity, and increased colony-forming units of bone marrow hematopoietic progenitor cells. In addition, TP 50 repaired radiation-induced organ damage. CONCLUSION: The current findings suggest that oral administration of TP 50 to beagle dogs effectively alleviated hematopoietic bone marrow dam- age induced by γ-radiation.

Natural Product Vibsanin A Induces Differentiation of Myeloid Leukemia Cells through PKC Activation.

All-trans retinoic acid (ATRA)-based cell differentiation therapy has been successful in treating acute promyelocytic leukemia, a unique subtype of acute myeloid leukemia (AML). However, other subtypes of AML display resistance to ATRA-based treatment. In this study, we screened natural, plant-derived vibsane-type diterpenoids for their ability to induce differentiation of myeloid leukemia cells, discovering that vibsanin A potently induced differentiation of AML cell lines and primary blasts. The differentiation-inducing activity of vibsanin A was mediated through direct interaction with and activation of protein kinase C (PKC). Consistent with these findings, pharmacological blockade of PKC activity suppressed vibsanin A-induced differentiation. Mechanistically, vibsanin A-mediated activation of PKC led to induction of the ERK pathway and decreased c-Myc expression. In mouse xenograft models of AML, vibsanin A administration prolonged host survival and inhibited PKC-mediated inflammatory responses correlated with promotion of skin tumors in mice. Collectively, our results offer a preclinical proof of concept for vibsanin A as a myeloid differentiation-inducing compound, with potential application as an antileukemic agent. Cancer Res; 76(9); 2698-709. ©2016 AACR.

The protein kinase C agonist prostratin induces differentiation of human myeloid leukemia cells and enhances cellular differentiation by chemotherapeutic agents.

As acute myeloid leukemia (AML) cells are characterized by uncontrolled self-renewal and impaired cellular differentiation, induction of terminal differentiation of leukemia cells by differentiating agents has been proposed as an attractive therapeutic strategy to treat AML. Here, we demonstrated that prostratin, a potent protein kinase C (PKC) activator, inhibited the growth of myeloid leukemia cells by a predominant G1 arrest with variable induction of apoptosis. Conversely, prostratin induced significant differentiation of AML cell lines and primary AML blasts as evidenced by morphology and immunophenotyping. The effects of prostratin were PKC dependent, and activation of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK) 1/2 by PKC was required for prostratin-induced cell differentiation. Consequently, prostratin reprogrammed transcriptional factor expression, and ectopic expression of c-Myc in HL-60 cells significantly eliminated prostratin-mediated cellular differentiation and cell cycle arrest, indicating an essential role for c-Myc suppression in the differentiation-inducing effects of prostratin. Finally, prostratin was able to potentiate cellular differentiation induced by chemotherapeutic agents such as Ara-C. Together, we proposed that prostratin alone or administered with other anticancer agents may be effective in differentiation therapy of AML.

[Protective effect of HS-6101 on rhesus monkeys with severe hematopoietic acute radiation sickness].

This study was purposed to investigate the protective effects of lipoprotein HS-6101(6101) on rhesus monkey total body irradiated with 7.0 Gy 6°Coγ-ray. A total of 30 health adult rhesus monkeys were randomly divided into symptomatic therapy (ST), WR2721 and HS-6101 30, 90 and 270 mg/kg groups (n = 6), the rhesus monkeys of each groups were injected with physiological saline 0.3 ml/kg, WR-2721 30 mg/kg, or HS-6101 30, 90 and 270 µg/kg, respectively. All agents were once intramuscularly injected at 1 hr prior irradiation. General observation, peripheral blood cell counts, colony forming unite assay of bone marrow hemopoietic progenitor cells, and histopathological examination were performed. The results showed that animals in symptomatic therapy group begin to die on the 13(th) day and 4 animals died within 24 days, the average survival time was 18.2 ± 4.3 days; 2 animals in WR-2717 groups died on day 15.8 and day 18.5 post irradiation respectively. 1 animal in HS-6101 270 mg/kg group died on day 35.8, all other animals survived. Nadirs of peripheral blood white blood cells, neutrophils and platelets of animals in HS-6101 treatment groups were significantly higher than those in other 2 groups including ST and WR-2721 groups, and the hemopoietic recovery were also significantly speeding up(P < 0.05 and 0.01). In vitro results showed that HS-6101 obviously promoted 7.0 Gy 6°Coγ irradiated monkey's bone marrow mononuclear cells to form various hematopoietic progenitor cell colonies (P < 0.05 and 0.01) . Compared with symptomatic therapy and WR-2717 groups, bone marrow histopathological changes in HS-6101 treatment groups showed more active hemopoietic cell proliferation and higher density structure. It is concluded that HS-6101 90 µg/kg treatment can promote the bone marrow recovery of 7.0 Gy 6°Coγ irradiated monkey, alleviate their animal symptom, simplify the treatment measures and improve the animal survival rate. The HS-6101 shows remarkable radioprotective effects as compared with the currently internationally acknowledged radioprotectant of WR-2721.

[Protective effects of WR2721 on early bone marrow hematopoietic function in mice exposed to 6.5 Gy of (60)Co γ-rays].

The aim of this study was to investigate the effect of WR2721(amifostine) against bone marrow hematopoietic damage of mice exposed to 6.5 Gy of (60)Co-γ ray. A total of 60 C57/BL6J mice was divided into 3 groups:normal group (mice were injected with physiological salt solution), irradiation group (mice were injected with physiologic salt solution before irradiation) and WR2721 group (mice were injected with WR2721 before irradiation). The WBC, neutrophil (Neut), Plt and RBC levels in peripheral blood of 3 group mice were counted within 60 days after irradiation; the bone marrow nuclear cells (BMNC) were counted at 2 and 24 hours after irradiation; the hematopoietic stem/progenitor cell (LK/LSK) level and colony formation capability were detected by flow cytometry at 2 and 24 hours after irradiation. The results indicated that the counts of WBC and neut at 4 and 18 days, Plt at 7-18 days and RBC at 10-30 day after irradiation in WR2721 group were higher than those in irradiation group (P < 0.05); the BMNC, LSK and LK levels obviously increased at 24 hours after irradiation (P < 0.05), the CFU-GEMM, CFU-GM, CFU-MK BFU-E and CFU-E all significantly increased at 2 and 24 hours after irradiation (P < 0.01), as compared with irradiation group. It is concluded that WR2721 can effectively alleviate early hematopoietic damage and promote the fast recovery of peripheral blood cells in mice exposed to γ-ray, suggesting that the WR2721 has significant radioprotective effect on hematopoietic system.

Severe acute radiation syndrome: treatment of a lethally 60Co-source irradiated accident victim in China with HLA-mismatched peripheral blood stem cell transplantation and mesenchymal stem cells.

This is a case report of a 32-year-old man exposed to a total body dose of 14.5 Gy γ-radiation in a lethal (60)Co-source irradiation accident in 2008 in China. Frequent nausea, vomiting and marked neutropenia and lymphopenia were observed from 30 min to 45 h after exposure. HLA-mismatched peripheral blood stem cell transplantation combined with infusion of mesenchymal stem cells was used at Day 7. Rapid hematopoietic recovery, stable donor engraftment and healing of radioactive skin ulceration were achieved during Days 18-36. The patient finally developed intestinal obstruction and died of multi-organ failure on Day 62, although intestinal obstruction was successfully released by emergency bowel resection.

Cylindroside A, a new triterpenoid saponin from Cylindrokelupha dalatensis and its cytotoxic activity.

A new triterpenoid saponin, named cylindroside A (1), was isolated from the seeds of Cylindrokelupha dalatensis (Kosterm.) T.L. Wu by using chromatographic method. The structure of 1 was established by comprehensive spectroscopic analysis and chemical degradation. Compound 1 displayed significant antitumor activity in vitro against BCG and MCF-7 cancer cell lines and IC50 values were 4.17 ± 0.23 and 3.07 ± 0.66 µM by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, respectively.

[Radiation protection effect of rhIL-12 on monkey hematopoietic system].

This study was aimed to investigate the radioprotective effects of recombinant human interleukin-12 (rhIL-12) on monkey hematopoietic system, and to provide experimental evidence for future clinical prophylaxis and treatment for patients who suffered from acute radiation syndrome. In in vitro study, the effect of rhIL-12 in different concentrations (0, 1, 5, 25, 125 and 625 ng/ml) on colony forming capacity of human or monkey bone marrow-derived mononuclear cells was examined in methylcellulose H4434 medium. In in vivo study, the acute radiation syndrome model was established in 11 Rhesus monkeys which received lethal total body irradiation by 6 Gy (60)Co γ in single time irradiation. The irradiated monkeys were randomly divided into 3 subgroups: control group (n = 4) which received subcutaneous PBS injection, rhIL-12 single-dose group (n = 3) which received subcutaneous single injection of rhIL-12 (4 µg/kg) at 2 h after irradiation, and multiple-dose group (n = 4) which received subcutaneous injection of rhIL-12 (1 µg/kg per injection) at 2 h, day 3, 6 and 9 after irradiation respectively. Peripheral blood cells were counted before and after irradiation every other day. The survival status of animals were observed daily. In vitro test results showed that different concentrations of rhIL-12 obviously promoted human and healthy monkeys' bone marrow mononuclear cells to form various hematopoietic progenitor cell colonies, especial CFU-E and CFU-GM. All animals in control group died within 22 d after lethal total body irradiation, average survival time was (20.3 ± 1.2) d. Only one monkey in multiple-dose group died due to anemia on day 17. All monkeys in single-dose group survived. Compared with control group, rhIL-12-administrated monkeys' white blood cell count, hemoglobin level, platelet and reticulocyte counts showed faster recovery from high dose radiation. It is concluded that the rhIL-12 treatment can promote the bone marrow hematopoietic stem/progenitor cell colony formation in vitro and protect lethally-irradiated monkeys. There is an obvious therapeutic effect of rhIL-12 on monkeys suffered from bone marrow failure caused by severe acute radiation exposure.

[Transfection of ECSOD to Rhesus bone marrow mesenchymal stem cells in vitro].

This study was aimed to investigate the biological effects of Rhesus bone marrow mesenchymal stem cells (R-BMMSC) transfected by adenovirus bearing extracellular superoxide dismutase gene (AD-ECSOD). Using density gradient centrifugation and adherent culture way, the R-BMMSC transfected by AD-ECSOD and reporter gene EGFP were isolated, cultured and purified; the transfection efficiency was detected by fluorescence microscopy and flow cytometry; the ECSOD protein expression in cell culture supernatant were detected by ELISA; the surface antigens on R-BMMSC (CD34, CD29, CD45, CD90, HLA-DR) were detected by flow cytometry; and differentiation capability of transfected R-BMMSC were detected by oil red O and alizarin staining; the proliferation capability of R-BMMSC was assay by MTT method. The results showed that the transfection efficiency of AD-ECSOD (MOI 500, 1 000, 1 500 and 2 000) for R-BMMSC was > 95%. At 24 h after transfection, the ECSOD protein could be detected in cell culture supernatant, and its level was significantly higher than that of control group (P < 0.01). At 48 h after transfection, the expression level of ECSOD protein on MOI 1 500 and 2 000 was the highest. The proliferative capability, surface antigen expression and multi directive differentiation ability of transfected R-BMMSC were similar to non-transfected R-BMMSC. It is concluded that the AD-ECSOD can effectively transfect the R-BMMSC without influences on its biological features.

High dose granulocyte colony-stimulating factor enhances survival and hematopoietic reconstruction in canines irradiated by 2.3 Gy mixed fission neutron and gamma ray.

This study was purposed to evaluate the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on hematopoietic reconstruction and survival in beagles exposed to mixed fission neutron and γ-ray. 13 beagles were unilaterally exposed to single dose of 2.3 Gy 90% neutrons. The experiments were divided into 3 groups: irradiation control group (no any treatment, n = 4), supportive care group (n = 5) and rhG-CSF plus supportive care group (n = 4, abbreviated as rhG-CSF group) in which the beagles were subcutaneously injected with 200 µg/kg of rhG-CSF early at half an hour and 24 hours post-irradiation respectively. The results showed that 2.3 Gy 90% neutron irradiation induced a severe acute radiation sickness of bone marrow type. The administration of rhG-CSF increased the survival rate from 60% in supportive care group to 100%. Twice injection of rhG-CSF in the first 24 hours reduced duration of neutropenia, enhanced neutrophil nadir and promoted neutrophil recovery when compared with control cohort administered clinical support. The number of colony-forming cells (CFU-GM, CFU-E, and BFU-E) in peripheral blood of rhG-CSF treated canines increased 2-to 5-fold relative to those of the supportive care group on day 3. All canines treated with rhG-CSF achieved hematopoietic reconstruction as evidenced by the pathological section of sternum while severe shortage of hemopoietic cells remained in the cohorts given supportive care alone. It is concluded that the combination of supportive care and high-dose rhG-CSF can accelerate hematopoietic recovery and enhance survival of dogs exposed to 2.3 Gy mixed neutron and gamma ray.

[New advance of research on therapy of severe acute radiation sickness with mesenchymal stem cells].

Mesenchymal stem cells (MSC) are a kind of non-hematopoietic adult stem cells with self-renewal and multilineage differentiation potential, which have special biological characteristics, such as secreting various cytokines, promoting hematopoiesis, accelerating stem cells homing and reconstructing hematopoietic microenvironment. MSC are collected and amplified easily, and can be transfected by exogenous gene. Many reports indicated that MSC were applied in therapy for variety of tissues and organs injury, meanwhile the treatment for acute radiation sickness has made significant progress. In this review, the biological characteristics and new research advance on MSC in treatment of severe acute radiation sickness are summarized and discussed.

RhG-CSF improves radiation-induced myelosuppression and survival in the canine exposed to fission neutron irradiation.

Fission-neutron radiation damage is hard to treat due to its critical injuries to hematopoietic and gastrointestinal systems, and so far few data are available on the therapeutic measures for neutron-radiation syndrome. This study was designed to test the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in dogs which had received 2.3 Gy mixed fission-neutron-γ irradiation with a high ratio of neutrons (~90%). Following irradiation, rhG-CSF treatment induced 100% survival versus 60% in controls. Only two of five rhG-CSF-treated dogs experienced leukopenia (white blood cells [WBC] count < 1.0 × 10(9)/L) and neutropenia (neutrophil [ANC] count < 0.5 × 10(9)/L), whereas all irradiated controls displayed a profound period of leukopenia and neutropenia. Furthermore, administration of rhG-CSF significantly delayed the onset of leukopenia and reduced the duration of leucopenia as compared with controls. In addition, individual dogs in the rhG-CSF-treated group exhibited evident differences in rhG-CSF responsiveness after neutron-irradiation. Finally, histopathological evaluation of the surviving dogs revealed that the incidence and severity of bone marrow, thymus and spleen damage decreased in rhG-CSF-treated dogs as compared with surviving controls. Thus, these results demonstrated that rhG-CSF administration enhanced recovery of myelopoiesis and survival after neutron-irradiation.

[Effect of rhG-CSF on blood coagulation in beagles irradiated by 2.3 Gy neutron].

The aim of this study was to investigate the effect of recombinant human granulocyte stimulating factor (rhG-CSF) on blood coagulation of beagles irradiated by 2.3 Gy neutron so as to provide new therapy for blood coagulation disorder after neutron irradiation. 10 beagles were exposed to 2.3 Gy neutron, and then randomly assigned into supportive care group and rhG-CSF-treated group. The rhG-CSF-treated cohorts were injected subcutaneously with rhG-CSF (10 µg/kg·d) beginning at the day of exposure for 21 consecutive days. Peripheral blood platelet counts were examined once every two days. In vitro platelet aggregation test, thromboelastography and blood clotting tetrachoric tests were also performed. The results indicated that the blood clotting system of irradiated dogs was in hypercoagulable state in the early days after 2.3 Gy neutron irradiation, and became hypocoagulable at crisis later and were mainly on intrinsic coagulation pathway. Blood fibrinogen increased markedly during the course of disease, while platelet counts and aggregation function were decreased remarkably. rhG-CSF administered daily could correct hypercoagulable state induced by 2.3 Gy neutron irradiation at the early time post exposure, shortened the thromboplastin generation time and clotting formation, down-regulated the abnormal high fibrinogen in blood, and improved platelet aggregation function. It is concluded that rhG-CSF can improve coagulation disorders of irradiated dogs.

Fluacrypyrim, a novel STAT3 activation inhibitor, induces cell cycle arrest and apoptosis in cancer cells harboring constitutively-active STAT3.

STAT3 protein has an important role in oncogenesis and is a promising anticancer target. Herein, we demonstrate that a novel small molecule fluacrypyrim (FAPM) inhibits the growth of leukemia cells by a predominant G1 arrest with significant decrease of the protein and mRNA levels of cyclin D1. As cyclin D1 is transcriptionally regulated by STAT3, FAPM is then shown to markedly inhibit the STAT3 phosphorylation with marginal effect on the other signal transducers and activators of transcription, and without effect on phosphoinositide-3-kinase and mitogen-activated protein kinase pathways. Further analysis shows that FAPM significantly increases the protein tyrosine phosphatases (PTPs) activity in a dose-dependent manner, and the inhibition of PTP activation by sodium pervanadate reverses FAPM-induced suppression of STAT3 tyrosine phosphorylation, indicating an important role of PTP in the action of FAPM. Finally, FAPM treatment results in selective suppression of STAT3-mediated transcriptional activity and its downstream effectors, and subsequent induction of growth arrest and apoptosis in STAT3-dependent cancer cell lines. This study therefore identifies FAPM as a potent STAT3 activation inhibitor with possible therapeutic potential against malignancies with constitutive STAT3 activation.

[Jak/STAT signaling pathway of IL-11 in the protection of intestinal epithelial cells from neutron radiation].

AIM: To explore the effect of IL-11 on the activation of Jak/STAT pathway and the expressions of Bax and Bcl-2 in the intestinal epithelial cells exposed to neutron radiation. METHODS: The BALB/c mice and IEC-6, irradiated by 4 Gy neutron with or without IL-11 treatment, served as in vivo and in vitro model seperately. The changes of the intestines, activity of Jak1 and STAT3 and expressions of Bax and Bcl-2 were observed by HE staining, Western blot, EMSA, immunohistochemistry and image analysis. RESULTS: (1)Mice exposed to neutron radiation showed severe intestinal damages and no obvious regeneration was seen. IL-11-treated mice had a larger number of cryptal epithelial cells and crypts. (2)Neutron radiation decreased the activities of Jak1 and STAT3, while IL-11 increased their activities. (3) Neutron radiation decreased the expression of Bax and didn't change the level of Bcl-2 in the murine intestine. IL-11 administration decreased the expression of Bax and increased that of Bcl-2. CONCLUSION: The mechanism of the intestinal protection of IL-11 in neutron irradiation might be that IL-11 stimulation triggered activation of Jak/STAT pathway, downregulated the expression of Bax and upregulated the expression of Bcl-2.

Relationship between individual radiosensitivity and radiation encephalopathy of nasopharyngeal carcinoma after radiotherapy.

PURPOSE: To analyze the relationship between individual radiosensitivity and the morbidity and severity of radiation encephalopathy (RE) induced by radiotherapy of nasopharyngeal carcinoma (NPC) patients. PATIENTS AND METHODS: In this study, 26 patients with RE (experimental group) and 26 patients without RE (control group) after radiotherapy of NPC were included. The experimental group was divided into two subgroups, that is, group 1 with 1-2 grade and group 2 with 3-4 grade, according to the RTOG/EORTC Score. Individual radiosensitivity was determined by the total chromosomal aberration rate measured in in vitro irradiated lymphocytes by a metaphase detection technique. Chromosomal aberration rate was correlated to development of RE in order to investigate the relationship between radiosensitivity and RE. RESULTS: The total chromosomal aberration rate was found to be a risk factor for the onset of RE. The total chromosomal aberration rate was positively correlated to the severity of RE. Patients with a high radiosensitivity had shorter latency than those with a low or intermediate radiosensitivity. CONCLUSION: In NPC patients, individual radiosensitivity as determined by the proportion of lethal chromosomal aberrations in in vitro irradiated lymphocytes might be associated with the development of RE and has the potential to predict the morbidity and severity of RE.

[Mesenchymal stem cells applied in therapy for acute radiation injury].

Mesenchymal stem cells are a kind of non-hematopoietic adult stem cells with selfrenewal and multilineage differentiation potential, which have special biological characteristics, such as secreting hematopoietic growth factors, reconstructing hematopoietic microenvironment, low immunogenicity, and can be transfected and expressed by exogenous gene. This article summarizes the biological characteristics of MSCs and their models of application to acute radiation disease in animals.

[Effect of IL-2 on the growth and apoptosis of intestinal epithelial cells radiated by neutron and mechanisms of IL-2 on the injured IEC-6].

AIM: To observe the effect of neutron radiation on intestinal epithelial cells 6 (IEC-6), to study the effect of IL-2 on the proliferation and recovery of neutron-injured IEC-6, and to investigate the regulatory mechanisms of IL-2 on the injured IEC-6. METHODS: 4Gy-neutron-injured IEC-6 were treated by IL-2, with or without the blocking agent JAK(1) (A77-1726). The change of proliferative activity and death manner of the treated IEC-6 were detected by MTT colorimetry and flow cytometry at 10, 15, 30 minutes and 1, 3, 6, 12, 24, 48, 72 hours respectively. The expression of IL-2Rbeta and the activation of JAK(1) of neutron-injured IEC-6 treated by IL-2 were detected by immunocytochemical stainning and Western blot. RESULTS: After IEC-6 were radiated by 4 Gy neutron for 24 hours, the proliferative activity of IEC-6 decreased markedly but increased strikingly after IL-2 treatment (P<0.05). The apoptosis of IEC-6 in IL-2-treated group decreased (P<0.05), but there was no obvious difference in necrotic cell number. After neutron-injured IEC-6 were treated by IL-2, JAK(1) was activated at 10 and 15 minutes, and the expression of IL-2Rbeta increased apparently at 24 hours. When treated by JAK(1) and IL-2, the proliferative activity of neutron-injured IEC-6 was much lower than that in IL-2-treated group. CONCLUSION: IL-2 can accelerate the proliferation of neutron-radiated IEC-6 and protect them from neutron injury. IL-2Rbeta and JAK(1) participate in the regulation of neutron-injured IEC-6 by IL-2.

Effect of recombinant human interleukin-11 on expressions of interleukin-11 receptor alpha-chain and glycoprotein 130 in intestinal epithelium cell line-6 after neutron irradiation.

AIM: To explore the effect of recombinant human interleukin-11 (rhIL-11) on the expressions of interleukin-11 receptor alpha-chain (IL-11Ralpha) and an additional signal transducer glycoprotein 130 (gp130) in intestinal epithelium cell line-6 (IEC-6) after neutron irradiation. METHODS: Cultured IEC-6 cells were exposed to 4.0Gy neutron and treated with 100 ng/mL rhIL-11 12 h prior to or immediately after irradiation. The apoptosis and necrosis rates and expressions of IL-11Ralpha and gp130 were observed by flow cytometry, immunohistochemistry, Western blot and image analysis. RESULTS: The apoptosis rate of IEC-6 cells was increased by irradiation at 6 h (P < 0.01), IL-11 stimulation resulted in a decreased apoptosis rate in irradiated IEC-6 cells (P < 0.05). In normal control IEC-6 cells, intense immunoreactivity of IL-11Ralpha was located within the cell membrane and cytoplasm. The level of IL-11Ralpha expression significantly decreased at 6 h after irradiation (P < 0.01) and restored at 24 h after irradiation. In IEC-6 cells treated with both radiation and rhIL-11, the level of IL-11Ralpha expression was higher than that of irradiated cells (P < 0.05). When it came to gp130 protein, it was located in the cytoplasm of IEC-6 cells. After irradiation, we found a progressive decrease in the expression of gp130 protein (P < 0.05) in 48 h post-radiation, while in rhIL-11-stimulated cells, it came back to normal level at 24 h after irradiation and decreased at 48 h, but was still higher than that of only irradiated cells (P < 0.05). CONCLUSION: rhIL-11 can protect IEC-6 cells from neutron irradiation. The protective effect of rhIL-11 might be connected with its ability to up-regulate the expressions of specific ligand-binding subunit IL-11Ralpha and signal-transducing subunit gp130.