Increased survival of embryonic nigral neurons when grafted to hypothermic rats

Hypothermia can reduce neuronal death caused by ischemia and traumatic brain injury. We therefore investigated whether mild hypothermia in rats receiving a transplant of embryonic mesencephalic rat tissue increases survival of the implanted dopaminergic neurons. Mild hypothermia (32-33 degrees C) during graft implantation and for the following 90 min significantly increased the survival of transplanted dopaminergic neurons to 171% of control values in normothermic (37 degrees C) rats. This demonstrates that treatment of the graft recipient for a relatively short period during and after surgery has a favorable effect on the survival of grafted dopaminergic neurons. These findings may be of importance for clinical neural transplantation trials which are in need of procedures that improve transplant survival.