NPC1 Mice Treated with 2HPβCD

The NPC1 mice (Npc1^nih/nih) we used originated from a colony at the National Institutes of Health. Control (Npc1^+/+) and homozygous (Npc1^−/−) mice were generated from heterozygous (Npc1^+/−) breeding stock on a pure BALB/c background. Pups were weaned and genotyped at 19 to 21 days of age. After weaning, all mice were fed a basal low-cholesterol rodent chow diet ad libitum as described.^{29 (link)} The mouse room had alternating 12-h periods of dark and light. Npc1^−/− and Npc1^+/+ mice that had not received any prior treatments were administered weekly a subcutaneous injection at the scruff of the neck of either normal saline or a 20% (w/v) solution (in saline) of 2HPβCD (Sigma-Aldrich Corp; product H107) starting when they were 49-days old. This provided an approximate dose of 4000 mg/kg bw.^{12 (link)} As described below, the treatment period varied according to the types of measurements to be made. Mice were studied in the fed state in all experiments except the one involving bile collection when they were fasted for 4 h beforehand. All experimental protocols were approved by the Institutional Animal Care and Use Committee of The University of Texas Southwestern Medical Center.