Aspartame (AsP), one of the most widely consumed artificial sweeteners, remains under scrutiny for its potential effects on cellular health. While generally considered safe at dietary levels, growing evidence links AsP to oxidative stress and mitochondrial dysfunction, yet its mechanistic actions remain unclear. In this study, we systematically examined the dose‐dependent effects of AsP in SH‐SY5Y neuroblastoma cells using fluorescence‐based electrophysiological measurements and Western blot analysis of protein expression. Based on XTT analysis, cells were treated with the selected AsP concentrations (0.3 and 3 mM), and mitochondrial membrane potential (MMP), cytosolic pH, reactive oxygen/nitrogen species (ROS/RNS), intracellular calcium levels (Ca 2+ i ), and apoptotic markers were examined. XTT analysis indicated a dose‐dependent response, with cell viability increasing to 2‐fold at 0.03 and 0.3 mM AsP, followed by a decrease to 1.69‐fold at 1 mM and 1.38‐fold at 3 mM relative to controls. Notably, Bax/Bcl‐2 expression remained unchanged, indicating that observed changes in XTT signals did not proceed through classical apoptotic pathways. AsP at the tested concentrations did not alter MMP; however, 0.3 mM AsP markedly increased ROS levels (21% increase), whereas 3 mM AsP was associated with a decrease in intracellular pH (20% decrease) and reduced RNS levels (66% decrease) in normoglycemic cells. Under hyperglycemia (HG), 0.3 mM AsP elicited a significant suppression of calcium overload (12% decrease), reduced ROS production (34% decrease), and restoration of MMP (25% repolarization). In contrast, 3 mM of AsP produced detrimental effects, including a reversal of the previous MMP improvement (14% repolarization) and elevated ROS (19% increase), compared to HG cells. Biochemical analyses showed a slight but not significant increase in NOS3 protein expression at 3 mM AsP in controls, while PKG and calnexin levels remained unchanged across the experimental groups. Collectively, these findings reveal a dual and dose‐dependent role of AsP. Low doses provide a protective, mitochondria‐stabilizing effect, whereas high doses disrupt redox and pH balance, culminating in mitochondrial dysfunction. This highlights that AsP toxicity is driven primarily by impaired mitochondrial integrity rather than apoptosis. By clarifying its mechanistic profile, this study underscores the importance of dosage and metabolic context in evaluating artificial sweetener safety.
Aljaser et al. (Thu,) studied this question.