Fluoxetine Combination with Metformin Enhances Neuroprotection in PC12 Cell Injury Model

Background: Depression is a multifactorial mood disorder with a high prevalence worldwide. To date, advances in drug discov-ery have widened therapeutic options with the synthesis of so-called selective serotonin reuptake inhibitors. Fluoxetine is the first selective serotonin reuptake inhibitor with a proven clinical efficacy and safety profile. Metformin, a first-line antiglycemic drug, has been shown to have antidepressant effects in patients with type 2 diabetes. However, the effectiveness of the combination of metformin and fluoxetine in the treatment of depression has not been investigated.Methods: PC12 (rat adrenal pheochromocytoma) cells were subjected to high-level corticosterone (200 mu M) and drug adminis-tration. Then the cell apoptosis was measured by a flow cytometry assay. The potential mechanism of the combined application of metformin and fluoxetine on PC12 cells was discussed using reactive oxygen species, intracellular Ca2+ analysis, immunoflu-orescence, and Western blotting.Results: Our results showed that a combination of metformin and fluoxetine decreased apoptosis, the level of reactive oxygen species, and intracellular Ca2+ accumulation. Furthermore, the combined administration lowered the P62 protein expression and the autophagosome ratio, while promoting the expression of LC3B (microtubule-associated protein B-light chain 3) proteins.Conclusions: The combined use of metformin and fluoxetine in PC12 was found to have a protective effect against corticos-terone. Mitochondrial apoptosis inhibition, autophagy flux unblocking, and activation of the AMPK (AMP-activated protein kinase)/BDNF (brain-derived neurotrophic factor) pathway may represent new approaches to enhance neuroprotection.

Automated summary

This study found that the combination of metformin and fluoxetine has a protective effect on PC12 cells, reducing cell apoptosis, reactive oxygen species levels, and intracellular calcium accumulation. The combined treatment also decreased P62 protein expression, increased LC3B protein expression, and unblocked autophagy flux. Inhibiting mitochondrial apoptosis, promoting autophagy, and activating the AMPK/BDNF pathway may enhance neuroprotection.