1. Application of stem cell transplantation in the treatment of cerebral palsy. Although there are many methods to treat cerebral palsy and certain efficacy has been achieved, the long-term prognosis of children with cerebral palsy is still an issue that needs attention. Finding a treatment that directly addresses the pathological basis of brain injury in cerebral palsy has been a hot topic of research. The potential efficacy of stem cells with unlimited or longer-term self-renewal ability and the ability to generate new progeny cells, which have been used with good results in some neurological diseases (e.g., stroke, etc.), makes people quite optimistic about the application of stem cell transplantation. Therefore, various experimental studies around stem cell transplantation for cerebral palsy have been conducted in recent years and have been gradually applied in clinical settings. Recently, a Russian research group conducted clinical trials on the implementation of stem cell therapy in 19 children under the age of 10 with congenital diseases such as cerebral palsy, hydrocephalus, and epilepsy, and by nine of them, their conditions improved. The most obvious effect was seen in a child with congenital blindness. However, the relevant experts also stressed that “we are not sure what function is responsible for this result” and that this therapy should still be treated with caution, “the main thing is not to affirm or deny it easily, but to continue the research carefully”. 2.The mechanism and method of stem cell transplantation Stem cells, as a class of undifferentiated cells or primitive cells, are early undifferentiated cells that have the ability to self-replicate and differentiate into at least one kind of functional cells; under certain conditions, stem cells can differentiate into functional cells in the body and form any kind of tissues and organs, i.e., they are “plastic”. “Under certain conditions, stem cells can be directed to differentiate into functional cells in the body and form any type of tissues and organs, i.e., they have “plasticity”. Recent studies have shown that embryonic stem cells and neural stem cells can be differentiated into neural cells in in vitro culture, and have achieved significant efficacy in transplantation experiments in mice and rats models. Neural stem cell transplantation generally requires the following stages: in vitro isolation, culture, induction, expansion – transplantation treatment – observation of migration, proliferation, differentiation, axonal growth, integration and transplantation effect of neural stem cells after implantation into the brain. 3.Stem cell transplantation indications Using neural stem cells, we can treat lateral sclerosis and trauma-induced spinal cord injury, central nervous system tumors, etc.; pancreatic stem cells and liver stem cells can treat chronic hepatitis; corneal stem cells can rebuild the eye surface or even reconstruct the cornea, etc. In pediatric neurological diseases, they have been used for the treatment of pediatric cerebral palsy, cerebral hypoplasia, neonatal hypoxic-ischemic encephalopathy, nuclear jaundice and other brain injury diseases and genetic metabolic diseases. It is generally believed that the most suitable diseases for stem cells are mainly tissue necrosis diseases, such as myocardial necrosis caused by ischemia; degenerative lesions, such as Parkinson’s disease; and autoimmune diseases. 4.Current problems Unfortunately, although encouraging progress has been made in animal experiments, it must be seen that there are just as many problems hindering the advancement of stem cell transplantation to the clinic. First, although embryonic stem cells and neural stem cells can differentiate into neural cells in in vitro culture, the percentage of differentiation into specific neural cells is not high, and there is a degree of variation in each artificially induced differentiation that does not allow for complete homogeneity of the output cells. It is unimaginable to transplant directly to patients a procedure that has not been standardized and that yields cells with a fairly random nature. Second, although other tissue stem cells, such as bone marrow-derived stem cells, can also differentiate to neuronal cells, few experiments have been performed to demonstrate that these transgermline differentiated cells with neuronal antigen markers are indeed functional neuronal cells. Third, the efficacy observed in previously performed transplantation experiments, and even clinical trials, does not provide a convincing material basis. The mechanisms of differentiation and functional repair of neural stem cells are still poorly understood, and further studies are needed to determine whether the transplanted cells can bind to cells in vivo and establish normal synaptic connections in the nervous system. The survival and value-added of neural stem cells in vivo also need to be tested. Whether there is any immune rejection between the transplanted neural stem cells and the body, and whether the transplanted neural stem cells can acquire all the characteristics of mature neurons are also among the issues that we still have not clarified. Fourth, the safety of transplantation is highly controversial. It should be noted that the risk of infection caused by transplanted cells, inflammation caused by injected cells and the risk of rejection all need further attention. In addition, the presence of tumorigenicity of stem cells is an international consensus and research focus. Fifth, the method and timing of transplantation still need to be further studied. At present, neural stem cells can be transplanted directly around the damaged area, or transplanted into the ventricles of the brain, or even injected directly from the subarachnoid space, the mechanism and effect of which are different and need to be further clarified. 5. Prospect With the deepening of research and the success of animal models, neural stem cell transplantation will gradually be applied in clinical treatment and has achieved obvious results. It is believed that in the near future, neural stem cell transplantation will play a great potential in all types of clinical brain injury and become one of the important means of clinical treatment of cerebral palsy.