Adropin Infusion in Hyperlipidemic Mice

Animal experiments were carried out in accordance with the Guide for the Care and Use of Laboratory Animals published by the National Research Council, with protocols approved by the Institutional Animal Care and Use Committee of Tokyo University of Pharmacy and Life Sciences (No. L17-22, 24 April 2017). A total of 22 male spontaneously hyperlipidemic Apoe^−/− mice (BALB/c. KOR/StmSlc-Apoe^shl mice) at 8 weeks old were purchased from Japan SLC (Hamamatsu, Japan) and fed a normal diet. At 13 weeks old, a high-cholesterol diet containing 1.25% cholesterol, 3.0% lard, and 1.625% glucose (F2HFD1; Oriental Yeast, Tokyo, Japan) was started [39 (link),40 (link),41 (link),44 (link),45 (link),46 (link),47 (link),48 (link),49 (link)]. At 17 weeks old, six mice were sacrificed as pre-infusion controls. The remaining 16 mice were divided into three groups of six, five, and five mice, and infused using osmotic minipumps (Alzet Model 1002; Durect, Cupertino, CA, USA) for 4 weeks with three doses of adropin (0, 5, 10 μg/kg/h), respectively. Doses of adropin were selected based on previous data [5 (link),9 (link),28 (link),29 (link)]. Pumps were implanted subcutaneously into the dorsum, and replaced once every 2 weeks under medetomidine-midazolam-butorphanol anesthesia [45 (link)].