Vitamin B6 Antidepressant Effects Are Comparable to Common Antidepressant Drugs in Bacillus-Calmette-Guerin Induced Depression Model in Mice

Bacillus-Calmette-Guerin (BCG) inoculation in mice produces an acute period of illness followed by a chronic depressive-like behavior period that lasts for few weeks. The aim was to evaluate vitamin B6 antidepressant effect in comparison with common antidepressants.

BCG (0.2 ml/mouse) single dose was intraperitoneally inoculated in male mice. Vitamin B6 (100 mg/kg), fluoxetine, imipramine, or venlafaxine (10 mg/kg each) were intraperitoneally injected for 14 consecutive days following BCG administration. Illness was evaluated following inoculation and depressive-like behaviors were assessed on days 7 and 14.

Illness was induced by BCG since mice lost weight and locomotor activity was reduced. Illness was prevented by vitamin B6 similar to antidepressant drugs. Despair was measured by immobility time during the forced swim test and BCG increased it compared to control (193 ± 3s vs 151 ± 7s, P < 0.01) on day 7, and (200 ± 5s vs 147 ± 6s, P < 0.001) on day 14. Vitamin B6, like antidepressants, reduced despair. BCG clearly induced anhedonia evaluated by sucrose preference test (47.5%), and it was soothed by B6 and the antidepressants. Novelty-suppressed feeding test evaluated long term depressive behavior after 14 days. BCG increased the latency to first feeding (222 ± 41s vs control 87 ± 2.6s, P < 0.001) and reduced food consumption per body weight (13 ± 1 mg/g vs control 19 ± 2 mg/g, P < 0.001) while B6 like antidepressants reduced latency and improved food consumption.

Vitamin B6 efficiently prevented BCG sickness and depression that was comparable to common antidepressant drugs. Therefore, B6 supplement for preventing depression in high-risk individuals is suggested for further clinical research.