Repair Effect Of Stem Cell Transplantation On Periventricular Leukomalacia In Neonatal Rats

Objective: Periventricular leukomalacia(PVL)is one of the most serious neurological complications in premature infants.In this study,the repair effect of human umbilical cord mesenchymal stem cells(hUC-MSCs)on neonatal rat PVL was studied by animal model.Methods:Totally 72 of 2-3-day-old SD rats were randomly divided into two groups,Control group(n = 24)and PVL model group(n = 48),which including transplantation PVL group(n = 24)and non-transplantation PVL group(n = 24).The right side of carotid artery was ligated and rats were under hypoxia environment for2.5 hours(mixed air of 8% O2 and 92% N2).At the time of 24 hours after modeling,hUC-MSCs was transplanted into the right lateral ventricle of rats in the transplantation PVL group.The morphological changes of brain tissue,the number of apoptotic cells and proliferative cells,the number and thickness of myelin sheath and neurobehavioral changes were observed at 3-days,7-days and 14-days post transplantation respectively.The changes were compared with those in the non-transplantation group and the Control group at the corresponding time point.Results: Seven days after modeling,the loose structure of white matter,disordered arrangement of nerve fibers,pyknosis and degeneration of neurons,coagulative necrosis and cystic cavity formation were observed under light microscope,and some green-stained apoptotic cells could be seen under fluorescence microscope.The pathological changes of brain tissue in the transplantation PVL group were slighter than those in the non-transplantation PVL group,and the number of apoptotic cells in the transplantation PVL group was less than that in the non-transplantation PVL group.Under electron microscope,rare myelin formation was observed in the corpus callosum of rats in the non-transplantation PVL group,and the thickness of myelin sheath was significantly smaller than that in the control group(p < 0.05).The myelin sheath number of corpus callosum in the transplantation PVL group was slightly more than that in the non-transplantation PVL group(p < 0.05),and the myelin sheath thickness in the transplantation PVL group was slightly larger than that in the non-transplantation PVL group(p < 0.05).Three days after modeling,less proliferation of brain cells was observed in the non-transplantation PVL group,while more proliferation of human umbilical cord mesenchymal stem cells and nerve cells were observed in the transplantation PVL group.Fourteen days after modeling,the spatial position perception and learning and memory ability of rats in the transplantation PVL group were better than those in the non-transplantation PVLgroup.Conclusion: The rat model in accordance with the pathological changes of PVL can be successfully established by ligation of the right side carotid artery and under hypoxia environment for 2.5 hours.After stem cell transplantation,the pathological changes of brain,the number and thickness of myelin sheath and the neurobehavioral performance of rats in the transplantation PVL group were better than those in the non-transplantation PVL group.Human umbilical cord mesenchymal stem cells could specifically migrate to the injured site and proliferate and differentiate into nerve cells to play the role of repair.Stem cell transplantation has a certain effect on PVL rat.