Melatonin pre-treatment is a factor that impacts stem cell survival after transplantation

When melatonin, a hormone secreted by the pineal gland, was used as a pre-treatment for mesenchymal stem cells prior to their transplantation into the brains of laboratory animals to repair damage from stroke, researchers in China found that the stem cells survived longer after transplantation.

http://medicalxpress.com/news/2013-07-melatonin-pre-treatment-factor-impacts-stem.html