Duloxetine-Induced Neural Cell Death and Promoted Neurite Outgrowth in N2a Cells.

Duloxetine is a clinical drug that is primarily used for treatment of depression and pain, but it has side effects of addiction and tolerance. Cytochrome P450 (CYP) is its metabolic enzyme, and the drug's biofunction results from its neuro-protective effect in animal and cell models. We aimed to investigate the duloxetine-induced neural cytotoxicity effect and its performance in an N2a cell neurite outgrowth model. Cell death was assessed as cell viability using a Cell Count Kit-8 and further evaluated using bright-field images, propidium iodide (PI) and annexin V staining, colony-formation analysis, TUNEL staining of the cells, and biochemical testing. N2a cells were committed to differentiation by serum withdrawal and RA induction, and the neurite outgrowth was evaluated as the number of differentiated cells, longest neurite length, and average neurite length. Cell cycle analysis, PI and annexin V staining, mRNA expression, and biochemical testing were used to evaluate the drug effects on differentiation. The induction of neural cell death by duloxetine was not affected by classic cell death inhibitors but was promoted by the CYP inducer rifampicin. N2a cell neurite outgrowth was promoted by duloxetine via reduction of the CYP2D6 and MDA levels and induction of Bdnf protein levels. Duloxetine induces neural cell death through effects on CYP and promotes N2a cell neurite outgrowth by regulating CYP, Bdnf protein, and the intracellular lipid peroxidation level.

Genotoxic Evaluation of Duloxetine II. The Effect on the Number of Sister Chromatid Exchanges, the Mitotic Index, and the Proliferation Kinetics in Mouse Bone Marrow.

Duloxetine is an antidepressant which has showed valuable results, particularly in patients with major depression. This type of drugs is known to require genotoxic studies as part of their preclinical safety evaluation. In the case of duloxetine, however, there have been controversial results. Therefore, we considered it worthwhile to extend studies on the matter in an attempt to reach a conclusion. The present assay was made in mouse bone marrow to evaluate the capacity of the drug to induce sister chromatid exchanges (SCE), as well as to modify the proliferation kinetics and the mitotic index. Three doses of the antidepressant were tested (2, 20, and 200 mg/kg), besides the control mice were administered with purified water, and the positive treated animals administered with 1 mg/kg of doxorubicin. The results indicated a moderate but significant increase of SCE with the three tested doses, no effect regarding the mitotic index and a small reduction in the proliferation kinetics. Although in our assay the drug showed a lower effect, the present study agreed with a previous report that analyzed the amount of micronuclei in mouse peripheral blood, and it confirmed the relevance of evaluating the genotoxic effect of antidepressants, specifically duloxetine by applying diverse tests.