Potential antidepressant properties of cysteamine on hippocampal BDNF levels and behavioral despair in mice

Several studies have demonstrated that antidepressants increase central brain-derived neurotrophic factor (BDNF) levels, suggesting that BDNF signaling is important for the therapeutic mechanism of antidepressants. Recent work has found that cysteamine and its related agent, cystamine, are neuroprotective in Huntington's disease mice, and act by enhancing the secretion of central BDNF. In the present study, the potential antidepressant effects of cysteamine were examined by behavioral paradigms and biochemical assay. Male BALB/CByJ mice were given a single dose of normal saline, 10 mg/kg of imipramine or either 50, 100 or 200 mg/kg of cysteamine (i.p.) 30 min before undergoing the forced-swimming test (FST) or the tail suspension test (TST). Other groups of mice treated with the same drugs and doses, without behavioral tests, were sacrificed for hippocampal BDNF measurements. We found that, compared with the control group, the cysteamine 200-mg/kg group showed a significant reduction in immobility time in the FST (P < 0.01) and TST (P < 0.01), and showed lower activity in the open field test (P < 0.01). A significant increase in hippocampal BDNF levels was found in the cysteamine 200-mg/kg group (P < 0.05). Our findings suggested that cysteamine may possess an antidepressant-like effect, which may be mediated by increasing central BDNF levels.