Insulin attenuates 6-hydroxydopamine induced cell death in human neuroblastoma cells and restores p-Akt/t-Akt level

Introduction: Human neuroblastoma cell line is used in studying Parkinson’s disease (PD) due to its similarities to dopaminergic neurons. 6-hydroxydopamine (6-OHDA), a catecholaminergic neurotoxin, has been widely used to induce cell death in cellular models of PD. Although the brain glucose entry is not dependent on insulin, this peptide has been reported to have a role in PD, in which insulin signaling disruption is reported. This study aimed to evaluate, if insulin is efficient in preventing 6-OHDA induced cell death in human neuroblastoma cells as well as its effect on phoshorylated Akt (p-Akt)/total Akt (t-Akt) ratio. Methods: The cells -grown in DMEM/F12 media supplemented with 10% fetal bovine serum- were exposed to 6-OHDA with/without insulin for 24h, and then MTT assay was done to examine their viability. A pilot study was performed to assess the protective doses of insulin and accordingly the doses 0.9 and 1mM were selected. Western blot assay was done to evaluate the effect of 6-OHDA or insulin on p-Akt and t-Akt level. Results: The results indicated that insulin has potency to prevent SH-SY5Y cell death, and p-Akt/t-Akt decline induced by 6-OHDA. Conclusion: The results suggested insulin as a protective agent in dopaminergic cells.