Validation of reference genes for normalization of real-time quantitative PCR studies of gene expression in brain capillary endothelial cells cultured in vitro.

•10 reference genes were evaluated for use in quantification of mRNA expression in brain endothelial cultures.•The optimal number of reference genes for investigation relative changes within one type of culture setup was two.•For comparison of relative expression in monocultures, the optimal genes were PMM-1 and GAPDH.•For contact co cultures β-actin and HPRT1 showed robustness for quantification.•For comparisons of gene expression over culture time, YWHAZ, SDHA, RPL3A and PMSB6, provided the best robustness.