“…Bovine microvascular retinal endothelial cells were isolated from 3-month-old bovine eyes (Research 87, Inc., Boylston, MA) and used at P4-P10. Cells were plated on tissue culture dishes coated with 0.2% gelatin (Sigma) and maintained in M199 medium that contained 20% bovine calf serum (Hyclone, Logan, UT), 100 g/ml heparin, 12 g/ml bovine pituitary extract (Hammond Cell Tech, Windsor, CA), and 100 units/ml penicillin G and 100 g/ml streptomycin C (Gemini Bioproducts, West Sacramento, CA) as described previously (19,20). Cell culture medium was replaced every 2 days unless cultures needed to be passaged for in vitro tube assays.…”