Objective: To explore the methods of culturing highly purified rat brain microvascular endothelial cells(BMEC). Method: BMEC of SD rats were prepared by filtering through a mesh

and digested by collagenase. Then the cells were examined under microscope and the expression of factor Ⅷ polyclone antibody was determined. Result: The cells became polygon arranging as single layer in 1-2 days. In 7-10 days

the cells arranged as ovum-like in compact monolayer. Immunocytochemistry of factor Ⅷ polyclone antibody showed positive in cytomembrane and cytoplasm

but negative in cell nucleus. Most of the cells were found to express factor Ⅷ-related antigen. Conclusion: Ideal rat brain microvascular endothelial cells can be cultured by the improved cultural method of double filtering and digestion.