Effects of dental pulp stem cell transplantation on the long-term behavior and camp response element binding protein in neonatal rats with hypoxic ischemic brain damage

BACKGROUND: cAMP response element binding protein (CREB) is a key protein of memory, which is closely related to long-term memory. It will provide a new way for the treatment of hypoxic ischemic brain damage (HIBD) to study the effects of dental pulp stem cells transplantation on the long-term behavior and CREB protein via the lateral ventricle in neonatal HIBD rats. OBJECTIVE: To observe the changes in long-term behavior and CREB protein expression in neonatal HIBD rats after human dental pulp stem cell transplantation, thereby providing scientific evidence for clinical treatment of neonatal HIBD. METHODS: Thirty-six healthy 7-day-old Sprague-Dawley rats were randomly divided into normal, HIBD and cell transplantation group. The hypoxic ischemic brain damage models were established in the brain damage and cell transplantation groups. Twenty-four hours after HIBD, human dental pulp stem cells were injected into the left lateral cerebral ventricle of rats in the cell transplantation group, totally 3×10 6 living cells. Equal volume of normal saline was injected into the left lateral cerebral ventricle of rats in the normal control and HIBD groups. RESULTS AND CONCLUSION: The average time to seek water, the average escape latency and escape distance of the human dental pulp stem cells group were significantly shorter than those of hypoxic ischemic brain injury group (P < 0.01), but longer than those in the normal group (P < 0.01). Nissl staining showed that the cells in the hippocampal CA1 region in human dental pulp stem cells group were more regular, the number of cells was significantly higher than that of hypoxic ischemic brain injury group, but still significantly less than that in the normal group (P < 0.05). Immunohistochemical staining results showed that the number of CREB positive cells in human dental pulp stem cells group was significantly higher than those in HIBD group, but still significantly less than those in the normal group (P < 0.01). It is suggested that human dental pulp stem cells transplantation could promote the expression of CREB protein in the hippocampal CA1 region, to improve the long-term learning and memory ability of hypoxic ischemic neonatal rats, and thus repair HIBD.