Role of BIX01294 in the intracranial inhibition of H3K9 methylation lessens neuronal loss in vascular dementia model

Abstract Dementia develops as a result of multiple factors, including cerebrovascular disease which is called vascular dementia (VD). Histone‐3 lysine‐9 dimethylation (H3K9me2) broadly increases during VD and inhibits neuroprotective gene expressions. So, we aimed to determine how H3K9me2 inhibitor (BIX01294) affects neuronal damage in VD. An in vivo model of VD was used followed by BIX01294 treatment. Behavioral tests, hematoxylin, and eosin (H&E), Congo red, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were carried out. Hippocampal phosphorylated cyclic‐AMP responsive element binding protein (p‐CREB), c‐fos, brain‐derived neurotrophic factor (BDNF), and H3K9me2, were detected by western blot analysis technique. Neurological deficit and anxiety‐related behavior significantly reduced in the treatment group compared to the VD group ( p < 0.05). BIX01294 improved spatial and passive avoidance memory ( p < 0.01 and p < 0.05, respectively) compared to the VD group. Treatment with BIX01294 restored the level of p‐CREB/CREB ratio ( p < 0.05), cfos ( p < 0.01), BDNF ( p < 0.01), and suppressed H3K9me2 ( p < 0.001) when compared to the VD group. BIX01294 microinjection reduced the apoptosis level in TUNEL staining ( p < 0.05), and raised neural cell count in H&E staining ( p < 0.01); amyloid beta accumulation significantly decreased in the treatment group ( p < 0.05) compared to the VD group. In conclusion, long‐term treatment with a low dose of BIX01294 can prevent the progression of neuronal loss in VD model by raising the expression of neurotrophic factors, and reducing the apoptosis level.