HPCD treatment by subcutaneous injections: effects on retinal cholesterol of Cyp27a1−/−Cyp46a1−/− mice. Dots represent individual measurements in mouse retina (5–8 mice per group). The total cholesterol content is a sum of the esterified and unesterified cholesterol. Statistical significance for changes in total cholesterol in HPCD-treated vs control mice was assessed by the Mann-Whitney U test. *P ≤ 0.05. 2x, 2 injections; 3x, three injections; Cntrl, control mice; BW, body weight; Tx, HPCD-treated mice.