| The occurrence rate of burned injury could reach2%of the population per yearin China. Severe burned injury can be critical, thus draw constant attention fromsocial and medical society. The intestinal barrier would receive crucial damage fromsevere burns, which would lead to intestinal microorganism migration andendotoxemia, if not proper treated, it could further develope into multiple organfailure. Death caused by empyrosis shock has been decreased thanks to the betterunderstanding of burning, so multiple organ failure has become a major cause forcasualties in burn victims, which is counter measured mainly by replenish bloodvolume and anti-infectious treatments, unfortunately with unsatisfying outcomes. Ithas become a critical issue that how can organ dysfunction caused by burned injury betenuated and further repaired. Liver, amongst them all, is an indispensable metabolicorgan, and can protect the other organs from damage caused by burning. Therefore, itis very important for prevence and treatment of multiple organ failture to repair thelive injury after severe burns. Bone mesenchymal stem cells (BMSCs) are one kind ofpluripotent stem cells, which is multilineage differentiation, low immunogenic, easyto aquire, easy to separation and culture, capability to home into injured organs andrepair them, BMSCs possess a broad prospect in repair of ailing and injured tissues.There has been studies showing that BMSCs can repaire the local burn wound bylocal application and all kinds of liver deseases by vein transplantation, but it has notbeen reported that whether BMSCs can cure liver injury caused by severe burns byvein transplantation. With all being said, in this study, BMSCs were transplanted intosevere burned rat, and then their repair effect on the liver injury caused by severeburns was explored, which will find theoretical and experimental evidence for clinictreating on severe burns.Adherent culture methods were applied to separate and purify, flow cytometrywere used to examine cell cycle and surface markers after BMSCs were expanded, BMSCs were induced to differentiate into osteocytes. The adult male Wistar rats wererandomly asigned to normal control group, model group (0.1mL saline were injectedinto retro-orbital veins) and cell therapy group (0.1mL BMSCs were injected intoretro-orbital veins,1×107),10animals per group. The burned rat models wereestablished, BMSCs labeled by CM-Dil were transplanted through retro-orbitalinjection, rats in the model group were administrated the same volume of saline. Thegeneral status of rats was observed daily, bodyweights and wound healing areas weremeasured1week and2weeks after transplantation, and healing rate were counted.The liver tissue of rats were harvested2weeks after transplantation, ALT, AST andLDH in the serum were detected; the pathohistological changes were observed by HEstaining, and the pathohistological scores were performed; the expression of PCNAwas detected by immunohistochemistry; the apoptotic percentage of liver cells wasdetected by TUNEL method; the expression of Bax, Bcl-2, Caspase-3and P-ASK1was determined by Western blot, by which liver functionality and pathology, liver cellproliferation, apoptosis and apoptosis related protiens expression were observed.2weeks after transplantation, Laser Scanning Confocal Microscope was applied toobserve the engraftment of BMSCs in liver tissue of the rats.The result showed: BMSCs by adherent cultured growed abundently. The resultsof flow cytometery showed that the cultured BMSCs were positive for CD44andCD90, barely expression with CD45, most cells exsited at the inactive quiescent phase.BMSCs were induced differentiated to osteocytes and were stained by alizarin red.2weeks after transplantation, the rats in model group were inactive and lazy, the rats incell therapy group acted better. The body weghts and wound healing areas in celltherapy group were significantly better than those in model group (P<0.05). ALT, ASTand LDH test results showed that the liver functionality in cell therapy group weresignificantly better than that in model group (P<0.05). HE staining and pathologicalscoring showed that the morphology changes in cell therapy group were better thanthat in model group. Immunohistochemistry results showed that the expression ofPCNA in cell therapy group was significantly greater comparing to model group(P<0.05). TUNEL test results showed that the apoptosis percentage of liver cells in cell therapy group was significantly lesser comparing to model group (P<0.05).Western blot results showed that, comparing to normal control group, the expressionof Bax, Caspase-3and P-ASK1in model group was significantly higher (P<0.05),while Bcl-2significantly lower (P<0.05), and the Bcl-2/Bax ratio significantly lower(P<0.05). Comparing to model group, the expression of Bax, Caspase-3, P-ASK1incell therapy group was significantly lower (P<0.05), while Bcl-2significantly higher(P<0.05), and the Bcl-2/Bax ratio significantly higher (P<0.05). Under theobservation of Laser Scanning Confocal Microscope, BMSCs labled by CM-Dil couldbe seen in liver tissue of the rats in cell therapy group.Conclusion:BMSCs could home in the injured liver tissue after vein transplantation,exhibiting obvious repair effect on liver injury caused by severe burn, and theprobable machnisms may be associated with the promotion of liver cell proliferationand the inhibition of apoptosis. |
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