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The kidney is the target of the acute toxicity of depleted uranium (DU). However, the mechanism of DU‐induced cytotoxicity is not clear. The study was to demonstrate the role of autophagy in DU‐induced cytotoxicity and to determine the potential mechanism. We confirmed that after a 4‐h exposure to DU, the autophagic vacuoles and the autophagy marker light chain 3‐II in the human embryonic kidney 293 cells (HEK293) increased, and cytotoxicity decreased by abrogation of excessive autophagy using autophagy inhibitor. We also found activation of nucleus p53 and inhibiting mTOR pathways in DU‐treated HEK293 cells. Meanwhile, ethylmalonic encephalopathy 1 (ETHE1) decreased as the exposure dose of DU increased, with increasing autophagy flux. We suggested that by reducing ETHE1, activation of the p53 pathway, and inhibiting mTOR pathways, DU might induce overactive autophagy, which affected the cytotoxicity. This study will provide a novel therapeutic target for the treatment of DU‐induced cytotoxicity. [ABSTRACT FROM AUTHOR]

Background: Bone marrow-derived cells (BMDCs) have the ability to differentiate into intestinal epithelial cells after transplantation and participate in the regeneration process of damaged epithelium.Aims: To investigate whether BMDCs could differentiate into intestinal epithelium long term in chimeric mice after transplantation and without special treatment.Methods: Forty irradiated C57BL/6 mice were used. Thirty of them (group A) received transplantation of BMDCs from GFP transgenic mice, and ten (group B) received PBS. The chimeric percentage at the 14th month was examined by flow cytometry. Engraftment of BMDCs was detected by immunohistochemistry in intestinal epithelium. Immunofluorescence observation was used to detect coexpression of PCK, CD45 and Chromogranin A with GFP. BMDCs in the epithelium were observed by an immune electron microscope. The percent of GFP(+) epithelial cells was also determined by flow cytometry.Results: Mice in group A had a survival rate of 93.3% 1 week after transplantation. BMDCs could engraft into recipients' intestinal epithelium. These cells expressed epithelial cell marker PCK, but could not express CD45. Some of them differentiated into enteroendocrine cells expressing Chromogranin A. GFP(+) villous epithelial cells ranged from 9.41 to 16.07% in different subgroups of group A. BMDCs in epithelium developed the characteristics of enterocytes and goblet cells. GFP(+)/PCK(+) epithelial cells at the 6th month made up a proportion of 16.11% among all the isolated epithelial cells.Conclusions: Long term, BMDCs could repopulate recipient's intestinal epithelium even without any special treatment, which suggests a novel insight into the maintenance of the intestinal epithelial constitution. [ABSTRACT FROM AUTHOR]

Background: Cell-based transplantation, tissue engineering and gene therapy are important therapeutic strategies for present and future regenerative medicine. One challenge is to present the target cells in a suitable matrix to allow the cells to survive the wound contraction, tissue repair, and remodeling in certain tissues. Recently, functional biomaterial research has been directed towards the development of improved scaffolds and new drug delivery systems for regenerative medicine. Materials and methods: A literature survey was performed in basic and clinic publications relevant to the therapeutic potential of chitosan and its derivatives in regenerative medicine. In this review the functional properties and potential applications of chitosan and its derivatives in regenerative medicine are presented and discussed. Results: Chitosan can be obtained by alkaline deacetylation of chitin and is found to be a natural-based nontoxic, biocompatible, and biodegradable polymer with anti-microbial activity. Chitosan and its derivatives could accelerate wound healing by enhancing the functions of inflammatory cells and repairing cells. Recent studies further indicated that chitosan and its derivatives also are novel scaffold materials for tissue engineering and are-promising non-viral vectors for gene delivery. Conclusions: Regenerative medicine has entered a new era with the development of modern science and technology. The novel properties of chitosan make it a versatile biomaterial for cell therapy, tissue engineering and gene therapy. It is hoped that these diverse approaches for regenerative medicine will translate from “bench to bedside” in the future. [Copyright &y& Elsevier]

Multipotential bone marrow mesenchymal stem cells (BMSCs) are important in maintaining the microenvironment of the bone marrow (BM). Sympathetic nerves histologically innervate the BM; however, their role remains unclear. In this study, the effects of norepinephrine on DNA synthesis and the related signaling molecules involved in rBMSCs were examined. mRNA levels of the alpha1-adrenergic receptor subtypes increased following norepinephrine stimulation (10(-5) M for 30 min). DNA synthesis increased in dose- and time-dependent manners as determined by [(3)H]thymidine incorporation. Intracellular Ca(2+) concentration and translocation of protein kinase C from the cytosol to the membrane were also found to be elevated in rBMSCs. Phentolamine was able to suppress translocation of PKC. Norepinephrine also induced phosphorylation of ERK1/2, which was prevented by staurosporine treatment. Pretreatment with PD98059 inhibited ERK1/2 phosphorylation and DNA synthesis in rBMSCs. These findings indicate that norepinephrine stimulates DNA synthesis via alpha1-adrenergic receptors and downstream Ca(2+)/PKC and ERK1/2 activation in rBMSCs.

Objective: To investigate the myogenic differentiation of mesenchymal stem cells (MSCs) after being transplanted into the local muscle tissues., Methods: The serious muscle-injured model was established by the way of radiation injury, incising, and freezing injury in 36 mice. Purified MSCs derived from bone marrow of male mouse and MSCs induced by 5-azacytidine (5-Aza-CR) were transplanted into the local of normal muscle tissues and injured muscle tissues of female mouse. The quantity of MSCs and the myogenic differentiation of implanted MSCs were detected by the method of double labeling, which included fluorescence in situ DNA hybridization (FISH) and immunohistochemistry on the 1st, 3rd, 6th, 9th, 12th, and 15th day after transplantation., Results: The quantity of implanted MSCs decreased as time passed. MSCs' differentiation into myoblasts and positive expression of desmin were observed on the 15th day in purified MSCs group and on the 6th day in induced MSCs groups., Conclusion: MSCs could differentiate into myoblasts after being implanted into the local of muscle tissues. The differentiation occurs earlier in the induced MSCs group than that in purified MSCs group.

Background: The goal of our study was to examine the effects of whole body irradiation injury on tissue-repairing cells, so as to elucidate the possible mechanisms of reduced repopulation of tissue-repairing cells., Material/methods: The quantity of tissue-repairing cells in wounds from simple incision injury (WBI) (group S) and combined with WBI injury (group C) was measured histologically. The proliferation and apoptosis of tissue-repairing cells in wounds were determined using immunohistochemical staining for proliferation cell nuclear antigen (PCAN) and by TUNEL assay. Fibroblasts were isolated from the wounds, and their proliferation and apoptosis were detected in vitro. Some key molecules involving in proliferation (cyclin E and cyclin dependent kinase 4) and apoptosis (bcl-2 and bax) were also determined, so as to interpret the mechanisms of the alteration of tissue repairing cells., Results: The quantity of tissue-repairing cells in group C was significantly less than in group S. The PCNA contents in wounds of group C were significantly less than in group S, whereas the apoptosis of tissue-repairing cells in wounds of group C increased significantly as compared to group S. The expression of the molecules involved in the mediating of proliferation and apoptosis coincided with the proliferation and apoptosis of tissue repairing cells in wounds., Conclusions: The quantity of tissue repairing cells in wounds combined with WBI injury is significantly less than in simple incision injury. This is associated with both suppression of proliferation and increased apoptosis.

Objective: To study the effects of dosages of total body irradiation on the healing process of cutaneous wounds and to observe the changes of wound area at different periods after injury., Methods: The entire body irradiation from a (60)Co gamma-ray source was performed on Wistar rats. The single dosage varied from 1 to 8 Gy. Within 1 h after irradiation, two whole thickness circular cutaneous wounds corresponding to 2.5% of total body surface area (Phi = 22 mm) were produced on the back of the animals (combined injury groups). Same wounds were produced on rats with no irradiation (single wound group). Wound healing was observed at different points after injury., Results: After total body irradiation with the dose of 1, 2, 3, 4, 5, 6, 7 or 8 Gy, the wound healing was obviously retarded as the dosages increased. The wound area remained was larger in the large dosage groups than in the small dosage groups. Seven days after injury, there was 33.5% wound surface left unhealed in the single wound group, whereas in the combined injury groups, 35.4%, 38.1%, 41.6%, 48.8%, 53.9%, 63.7%, 69.2% and 73.9% of the wound surfaces remained unhealed, respectively. Statistical analysis showed marked correlations between the various times after total body irradiation and various dosages to the percentage of unhealed wound surface. Nine dose-effect relation formulae were deduced according to the statistical results., Conclusions: In soft tissue trauma combined with radiation injury, the delay of wound healing is related to the dose of radiation inflicted. It is also related to the time between injury and time of observation.

Objective: To investigate therapeutics for and the pathological basis of combined radiation and burn injuries., Methods: Combined radiation and burn injuries on mice and rats were inflicted by gamma ray irradiation from a (60)Co source and thermal radiation from a 5 kW bromotungsten lamp., Results: The dysfunction of myocardium played an important role in the development of early stage shock. Transfusion of irradiated (in vitro, 20 Gy) or stored (4 degrees C, 7 days) blood after irradiation was done to promote the success of allo-transplantation of bone marrow. Decrease of IL-4 mRNA expression was the molecular basis of depression of intestinal mucosa immune and intervention of IL-4 showed an antagonistic effect on enterogenic infection. A new lipid component extracted from burn eschar was documented for the first time and its toxic effects were elucidated. The survival rate of alloskin grafts after removal of burn eschar from the recipient animals was obviously increased in combined injury due to reduction of immune rejection activity by the radiation effect. In contrast, in animal models with simple burn, the alloskin grafts were all rejected within ten days after the procedure. A successful therapeutic result (survival rate: 92% for 30 days and 67% for 100 days) was obtained by comprehensive management of treated animals, while the untreated control animals all died within 3 - 7 days after injury., Conclusion: The pathogenesis of injury caused by simultaneous radiation and burn is extremely complicated and the treatment is very difficult. A comprehensive management program consisting of several therapeutic measures aimed at key links of the pathogenesis may achieve significantly improved results.

The effect of exogenous nucleotides on proliferation and migration of a normal rat small intestinal epithelial cell line IEC-6 is studied. The concentration-effects as well as interaction of exogenous nucleotides on proliferation of IEC-6 are measured by MTT. Migration of IEC-6 after wounded is determined by an in vitro model of intestinal epithelial restitution of IEC-6 monolayer. Expression of TGF beta is detected by immunohistochemistry. The results show AMP and GMP remarkably inhibit proliferation of IEC-6 in concentration-dependent manner respectively at 30 mumol/L or 150 mumol/L and more. CMP, UMP and nucleotides mixture can not enhance or inhibit the growth with the exception of inhibition of CMP on proliferation at very high concentration (1440 mumol/L). In contrast, CMP, especially UMP, can remarkably abolish the proliferation-inhibiting effects of AMP or GMP on the cell, when AMP or GMP is supplemented. Nucleotides mixture significantly facilitate migration of IEC-6 after wounded but fail to promote the expression of TGF beta. It is concluded that purine nucleotides inhibits proliferation of IEC-6. Pyrimidine nucleotides can abolish the inhibitive effects of purine nucleotides, and Nucleotides mixture promotes migration of IEC-6 after wounded by a TGF beta-independented way.