Stem cells from stem cells bank or cord blood banks have been isolated from various tissues in animals and humans, including adult bone marrow, cord blood, and even from adult brain. Human umbilical cord blood cells are rich in mesenchymal progenitor cells and contain a large number of endothelial cell precursors. Cord blood cells contain many immature stem or progenitor cells with extensive proliferation capacity in vitro. Human umbilical cord blood cells have been used as a source of transplantable stem and progenitor cells and as a source of marrow repopulating cells for the treatment of paediatric disease. Human umbilical cord blood cells have been used to reconstitute marrow in child with severe fanconi anaemia and to treat amyotrophic lateral sclerosis in mice. However, little is known about survival and development of human umbilical cord blood cells transplantation in the central nervous system.

In a recent study, intravenously infused human umbilical cord blood cells were tested to see if they can enter the brain, survive, differentiate in the ischemic brain microenvironment, and improve neurological functional recovery after stroke in rats. In addition, in vitro system was used to test whether ischemic brain tissue extract selectively induces chemotaxis of human umbilical cord blood cells. The behavioural scores were evaluated for normality and equal variances. Data transformation or nonparametric analysis approach would be considered if data were ill behaved. The balance of the baseline was also tested to see if variables would be included in the analysis for the treatment effect. Two control groups were involved in the study. Repeated measures were conducted to test the treatment by time interactions and the effect of treatment over time on each behavioural score. If an interaction of treatment by time or overall treatment effect was significant, then subgroup analysis would be conducted for the effect of treatment at each time. Otherwise, the subgroup analysis would be considered exploratory. The means and values for testing the difference between treated and control groups are presented.