2.5.1. Husbandry and dosing
Female and male Kun–Ming strain (KM) mice approximately 6 weeks old,
weighing 18–22 g, were obtained from Experimental Animal Center of Peking University
(Beijing, China). Following 5 day acclimatization they were divided randomly
into three groups, 12 mice for each group (six males and six females per
treatment). Then they were kept in stainless steel wire cages (two/cage) at 21–
23 C, relative humidity 40–60%, air change 15 times h1, and electric light from
09.00 to 21.00 animal rooms.
The Cry1Ab/Ac protein was dissolved in redistilled water and according to the
96.4% purity, the concentration of Cry1Ab/Ac protein was adjusted to 250 mg mL1.
Each mouse received 20 mL kg1 protein (5000 mg kg1 Cry1Ab/Ac protein for each
mouse) by gavage at the first day. BSA was used as negative control and water as
the blank control. The mice were given basal diet and tap water and observed for
14 days for any signs of morbidity or mortality. During the experimental period
all animals were inspected twice daily (Cage side). On day 15 at completion, all
the animals were anaesthetized by carbon dioxide inhalation and killed by exsanguinations
for gross and histopathological examination (Chinese Standard
GB15193.13-2003).