(A) CSI values of pooled gallbladder bile as a function of days on the lithogenic diet in WT, ABCG5(−/−)/G8(−/−), and ABCG8 (−/−) mice. (B) Photomicrographs of cholesterol monohydrate crystal and gallstone formation observed in mice after 14, 28, and 56 days on the lithogenic diet. Notably, although ABCG5(−/−)/G8(−/−) and ABCG8 (−/−) mice displayed significantly slower crystallization, growth, and agglomeration of cholesterol monohydrate crystals compared to WT mice, they still formed gallstones. All magnifications are 800x by polarizing light microscopy, except for the panels (400x) of day 28 for WT mice and of day 56 for ABCG5(−/−)/G8(−/−) and ABCG8 (−/−) mice, and the panel (200x) of day 56 for WT mice. (C) Gallstone prevalence was significantly higher in WT mice than in ABCG5(−/−)/G8(−/−) and ABCG8 (−/−) mice and (D) the frequency of stone number was assessed in these mice after 56 days on the lithogenic diet.