ABSTRACT
Previous studies have shown that melatonin can protect cells against rotenone-induced cell death. Yet, the mechanism involved in this protection requires further research. In this study, we aimed to further investigate the effects of melatonin on inhibiting rotenone-induced SH-SY5Y cells and the underlying molecular mechanisms. Human neuroblastoma SH-SY5Y cells were treated with 0.3 or 1µM rotenone for 6 or 12h. Cell viability was measured with an MTS assay, the mitochondrial membrane potential was determined with a Rhodamine 123 staining assay, and the protein expression levels of the markers of autophagy, including cytochrome C release (Cyt C), light chain 3B (LC3 B) and Dynamin-Related Protein 1 (Drp1) were analyzed by western blotting. The co-localization of Drp1 and TOM20 proteins in the mitochondria of SH-SY5Y cells was measured by immunofluorescence coupled with confocal microscopy and the overexpression of the Drp1 gene was then conducted. The viability and expression levels of Cyt C and LC3 B in rotenone and melatonin + rotenone-treated Drp1-overexpressed SH-SY5Y cells were analyzed with MTS and western blotting, respectively. We found that rotenone effectively induced SH-SY5Y cell death by causing mitochondrial dysfunction and increasing Cyt C expression. Drp1 expression and its regulation of mitochondrial translocation mediated the rotenone-induced cell death and melatonin inhibited this process. Overexpression of Drp1 protein attenuated melatonin's inhibition of rotenone-induced SH-SY5Y cell death. In conclusion, melatonin effectively inhibits rotenone-induced neuronal cell death via the regulation of Drp1 expression.
Subject(s)
Down-Regulation/drug effects , GTP Phosphohydrolases/metabolism , Melatonin/pharmacology , Microtubule-Associated Proteins/metabolism , Mitochondrial Proteins/metabolism , Rotenone/antagonists & inhibitors , Rotenone/pharmacology , Cell Death/drug effects , Cell Line, Tumor , Cytochromes c/metabolism , Cytoprotection/drug effects , Dose-Response Relationship, Drug , Dynamins , GTP Phosphohydrolases/genetics , Humans , Microtubule-Associated Proteins/genetics , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondrial Proteins/genetics , Neurons/cytology , Neurons/drug effects , Protein Transport/drug effectsABSTRACT
BACKGROUND: Patients with stroke suffer from nutrition impairments and often rely on enteral nutrition (EN), which is associated with respiratory complications such as regurgitation and aspiration. OBJECTIVE: To evaluate the incidence of regurgitation and aspiration in patients with severe stroke infused with different volumes of EN. METHODS: A randomized controlled trial was conducted on 210 patients with severe stroke undergoing EN therapy. Patients were randomly assigned into two groups. Subjects in the treatment group received EN with an initial rate defined according to the total volume and the infusion rate was adjusted based on gastric residual volume (GRV) assessed every 4 hours. Subjects of the control group received EN without monitoring the GRV and reached the target infusion volume within 72 hours. The incidence of reflux and aspiration was recorded. RESULTS: The incidences of regurgitation and aspiration were significantly lower in treatment group (6.3% and 7.9%, respectively) than control group (18.8% and 17.5%, respectively). In the treatment group, 1 patient developed regurgitation while 2 developed aspiration when EN was 500 mL. When EN increased to 1000 mL, 2 patients developed regurgitation and 2 developed aspiration, and 5 patients developed regurgitation and 6 had aspiration when EN was 1500 mL. There was no significant difference in the risk of reflux and aspiration when total volume of EN increased from 500 to 1500 mL. CONCLUSIONS: During EN therapy for patients with stroke, using feeding pump with a continuous infusion for 20 hours and adjusting infusion rate based on GRV could reduce the incidence of respiratory complications.
