Repair effect of transplantation of bone marrow mesenchymal stem cells on liver injury in severe burned rats and its mechanism

Objective To investigate the repair effect of transplantation of bone marrow mesenchymal stem cells(BMSCs)on liver injury in severe burned rats,and to clarify its mechanism.Methods The BMSCs of rats were isolated,cultured,amplified,identified,and labeled in vitro.30 Wistar rats were randomly divided into normal control group(n=10),model group(n=10)and cell therapy group(n=10).The burned rat model was established.The BMSCs labeled by chlormethyl-benzamidodialkylcarbocyanine(CM-Dil)were transplanted into therats in cell therapy group by retro-orbital intravenous injection and the saline was injected into the rats in model group.The general status of all rats were observed.The liver tissues of rats were obtained 2 weeks after transplantation,and the pathohistological changes were observed and the pathohistological scores were detected; the apoptotic rate of liver cells was detected by TUNEL method;the engraftment of BMSCs in liver tissues of the rats was observed under laser scanning confocal microscope.Results 2weeks after transplantation,the rats in model group were obviously malaise dispirited and the rats in cell therapy group showed obviously better,and the body weight of the rats in cell therapy group was higher than that in model group(P0.05).The pathohistological results showed the normal liver lobules of the rats in model group disappeared,and the liver cords disordered,and some liver sinusoids dilated and congested,lymphocytes infiltrated with occasional focal aggregating,and cell edema was found,cytoplasm loose and steatosis were seen in liver tissue.However,the pathohistological changes of liver tissue of the rats in cell therapy group were significantly better than those in model group.The pathohistological score of the rats in cell therapy group was significantly lower than that in model group(P0.05). The TUNEL staining results showed that there were lots of apoptotic liver cells in liver tissue of the rats in model group,and the apoptotic rate of liver cells in cell therapy group was significantly lower than that in model group(P0.05).CM-Dil labeled BMSCs were found in liver tissue of the rats in cell therapy group under confocal microscope.Conclusion BMSCs can implant into the damaged liver tissue after transplantation,and BMSCs have an obvious repair effect on liver injury caused by burning,and the possible mechanism may be associated with the inhibiting of apoptosis.