Enhancing tyrosine hydroxylase expression and survival of fetal ventral mesencephalon neurons with rat or porcine Sertoli cells in vitro

Sertoli cells (SCs) are testis-derived cells that secrete trophic factors important for the development of germ cells. Both porcine and rat SCs have been used as graft facilitators - neonatal porcine SCs to support islets in diabetes and 15-day-old rat SCs to enhance dopaminergic neuron transplants in Parkinson's disease models. However, there has never been a study examining the optimal SCs preparation to enhance tyrosine hydroxylase expression in the ventral mesencephalon (VM) neuron. The aim of this study was to compare the ability of both rat and porcine SCs to enhance tyrosine hydroxylase expression (TH) and neuronal survival at the same postnatal developmental ages. The SCs were isolated from 1-, 9-, or 15-day-old rat, or neonate (2-5 days), 2-month, or 4-month-old pig, and co-cultured with VM tissue from 13.5-day-old embryos. Our results showed that VM neurons co-cultured with SCs dispersed over the culture plate and had extensive neuritic outgrowth, while VM neurons cultured alone tended to cluster together forming a mass of cells with limited neurite outgrowth. TH expression was significantly increased when VM neurons were co-cultured with 15-day rat SCs or 2-month pig SCs but not when the cells were co-cultured with other ages of SCs. This suggests that secretion of trophic factors by SCs varies according to the developmental age, and it is critical for the success of graft facilitation that SCs from the appropriate age and species be used.