Gene targeting strategy for B-Bcrp KO mice. The exons 2~16 of mouse Abcg2 gene were knocked out in B-Bcrp KO mice, resulting in a disruption of the Abcg2 gene.

Strain specific analysis of Abcg2 mRNA expression in wild-type C57BL/6 mice and B-Bcrp KO mice by RT-PCR. Brain and kidney RNA were isolated from wild-type C57BL/6 mice (+/+) and B-Bcrp KO mice (-/-), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse Abcg2 primers. Mouse Abcg2 mRNA was detectable in wild-type C57BL/6 mice (+/+) but not in B-Bcrp KO mice (-/-).

Western blot analysis of BCRP protein expression in B-Bcrp KO mice. Various tissue lysates were collected from wild-type C57BL/6 mice (+/+) and B-Bcrp KO mice (-/-), and then analyzed by western blot with anti-BCRP antibody. 40 μg total proteins were loaded for western blotting analysis. BCRP was detectable in kidney, liver, heart of wild-type C57BL/6 mice (+/+) but not B-Bcrp KO mice (-/-).

Pharmacokinetic characteristic of B-Bcrp KO mice. Sulfasalazine pharmacokinetics in C57BL/6N mice co-administered with vehicle or Elacridar and in B-Bcrp KO mice. Mice received Sulfasalazine (5 mg/kg, PO) as a single dose. For C57BL/6N groups, either vehicle or Elacridar (50 mg/kg, PO) was administered twice daily (BID) with an 8-hour interval, with the first dose given 0.5 hours prior to Sulfasalazine. B-Bcrp KO mice received Sulfasalazine alone. Plasma samples were collected pre-dose and at 0.25, 0.5, 1, 2, 4, 8, and 24 hours post Sulfasalazine administration (N=3 male mice per group). The plasma concentrations of Sulfasalazine in both the C57BL/6N with Elacridar group and B-Bcrp KO mice group were higher than those in the C57BL/6N with Blank vehicle group.

Note: This experiment was conducted by Pharmaron using B-Bcrp KO mice.