In vitro optimization of retinoic acid-induced neuritogenesis and TH endogenous expression in human SH-SY5Y neuroblastoma cells by the antioxidant Trolox.

Though, it is quite well-known how retinoic acid (RA) is able to induce neuritogenesis in different in vitro models, the putative role exerted by reactive oxygen species (ROS) during this process still need to be further studied. For such purpose, we used a neuronal-like cell line (SH-SY5Y cells) in order to investigate whether the antioxidant Trolox (a hydrophilic analog of alpha-tocopherol) could have any effect on the number of RA-induced neurites, and how significant changes in cellular redox homeostasis may affect the cellular endogenous expression of tyrosine hydroxylase (TH). Our results show a significant enhancement of RA (10 μM)-induced neuritogenesis and TH endogenous expression, when cells were co-treated with Trolox (100 μM) for 7 days. Moreover, this effect was associated with an improvement in cellular viability. The mechanism seems to mainly involve PI3 K/Akt rather than MEK signaling pathway. Therefore, our data demonstrate that concomitant decreases in basal reactive oxygen species (ROS) production could exert a positive effect on the neuritogenic process of RA-treated SH-SY5Y cells.