To study the effect and mechanism of galangin in improving depression-like behavior in vascular dementia (VD) mice through microRNA-134 (miRNA-134).

Seventy C57BL/6J mice were randomly divided into sham group (0.9% NaCl), model group (0.9% NaCl), low-dose group (25 mg·kg^-1 galangin), medium-dose group (50 mg·kg^-1 galangin), high-dose group (100 mg·kg^-1 galangin), and mimic NC group (100 mg·kg^-1 galangin and mimic NC 15 nmol), miRNA-134 mimic group (100 mg·kg^-1 galangin and miRNA-134 mimic 15 nmol). The degree of depression was detected by tail suspension test and forced swimming test; the level of corticosterone was detected by enzyme-linked immunosorbent assay; the level of miRNA-134 was detected by quantitative real time polymerase chain reaction; the apoptosis rate of brain tissue cells was detected by TdT-mediated dUTP nick-end labeling; and the level of synaptic plasticity related protein was detected by Western blot.

The suspension time of the sham group, the model group and the high-dose group were (105.32±15.22), (185.32±24.62) and (112.65±15.08) s, respectively; the swimming time were (86.52±13.25), (152.32±22.22) and (96.22±16.35) s respectively; the levels of corticosterone were (32.65±5.02), (86.62±14.32) and (48.52±5.55) ng·L^-1, respectively; the levels of miRNA-134 were 1.00±0.12, 2.32±0.35 and 1.21±0.18, respectively. The apoptosis rates of the sham group, model group, high group, mimic NC group and miRNA-134 mimic group were (5.32±0.62)%, (62.33±8.65)%, (14.32±1.78)%, (15.85±2.22)% and (43.21±7.05)%, respectively; synaptophysin protein levels were 1.00±0.18, 0.32±0.05, 0.88±0.12, 0.82±0.11 and 0.30±0.05, respectively; the postsynaptic density protein-95 protein levels were 1.00±0.14, 0.61±0.07, 0.72±0.09, 0.70±0.08 and 0.45±0.06, respectively. The above indexes in the model group were compared with those in the sham group, those in the high-dose group were compared with those in the model group, and those in the miRNA-134 mimic group were compared with those in the mimic NC group, and the differences were statistically significant (all P<0.05).

Galangin may improve the depression-like behavior of VD mice by inhibiting the expression of miRNA-134, improving synaptic plasticity and inhibiting cell apoptosis.