Evaluation of the anti-depressant potential of metformin in conditioned defeat model in golden Syrian hamsters

Abstract

Background: Depression is a prevalent mood condition that has an impact on daily functioning. Globally, depression affects 264 million people. The current pharmacotherapy of depression has a lot of shortcomings. Therefore, there is a need to explore newer therapy that alleviate the symptoms of depression. Metformin was found to possess antioxidant potential and hypothesized to decrease the levels of branched-chain amino-acids essential for tryptophan uptake (precursor for serotonin synthesis). The study was designed to validate the efficacy of metformin as an anti-depressant in conditioned defeat model in male golden Syrian hamsters using open field test (OFT), forced swim test (FST) and Serum serotonin levels. Methods: After obtaining IAEC approval, the study was carried out using eight golden Syrian hamsters that were randomly assigned to four groups. The disease control group received 1mL normal saline, positive control was given fluoxetine 12 mg/kg, two groups of metformin 240 mg/kg given pre-insult and post-insult. The variables assessed on every third day included OFT and FST. Following the behavioral tests, serotonin-ELISA was done. To analyse the outcomes, appropriate statistical tests were applied. Results: On standardization, the model was established to a 16-day model. Further, results highlighted a significant difference in OFT, FST and serotonin levels with the metformin group and fluoxetine compared to disease control (p<0.001). However, no significant difference was observed between the fluoxetine and metformin groups (p>0.05), signifying the comparable results. Conclusions: Metformin (240 mg/kg) alleviated the depressive symptoms by modulating both behavioral and serotonin levels.