Vitamin D3 (VitD3) upregulates vitamin D receptor (VDR), osteopontin (OPN), decreases CD44 splicing and improves phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) in cerebral arteries after SAH. Representative Western blots (upper panel) and quantitative analysis (lower panel) of VDR (a), OPN (b), CD44 (c), AMPK (d) and phosphorylated AMPK (p-AMPK) (e) in cerebral arteries after SAH induction. Pre-SAH+VitD3, pretreatment (30 ng/kg) VitD3 24 h before SAH induction; siRNA, small interfering ribonucleic acid; *P < 0.05 vs. Sham. †P < 0.05 vs. Pre-SAH + VitD3+Control siRNA. n = 5 per group.