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

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 8 golden Syrian hamsters each 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