2.2 Animal studies
Mdr2−/− mice (7 weeks old, 20-22 g, male and female)
were housed and maintained under specific pathogen-free conditions in a
standard environment with a 12-hour light–dark cycle and fed a diet of
normal chow ad libitum . All animal studies and procedures were
sanctioned by the Institutional Animal Care and Use Committee of Beijing
University of Chinese Medicine and performed in compliance with all
guidelines and regulations. After acclimatization for 1 week, mice were
randomly divided into 4 groups (n = 6): (1) wild type (WT) group; (2)
Mdr2−/− group; (3) Mdr2−/− + PIC Ⅱ
low dose (L) group (5 mg/kg); (4) Mdr2−/− + PIC Ⅱ high
dose (H) group (10 mg/kg). Mice in group (1) and (2) were given saline
and mice in groups (3)-(4) were administrated with two different doses
of PIC Ⅱ for 14 days. In the macrophage depletion experiment, mice were
randomly divided into 4 groups (n = 6): (1) WT group; (2)
Mdr2−/− + empty liposome (Neg) group; (3)
Mdr2−/− + clodronate liposome (CL) group; (4)
Mdr2−/− + CL + PIC Ⅱ group (10 mg/kg). Mice in group
(2) were given empty liposome and mice in groups (3)-(4) were
administrated with clodronate-liposomes (1 mg/ml, 50 μl/mouse, YEASEN,
Shanghai, China) through tail vein once every three days until the day
before sacrificed. Mice in group (4) were also administrated with 10
mg/kg PIC Ⅱ for 14 days. After treatment, all mice in different groups
were sacrificed to obtain blood and liver samples for following
experiments.