Mouse model
Male C57BL/6 mice aged 8 weeks were purchased from the Experimental
Animal Center of Xi’an Jiaotong University. Mast Cell-Deficient C57BL/6
STOCK KitW-sh/W-shmice and MrgprB2 deficient (MUT) mice were purchased from the Model
Animal Research Center of Nanjing University. The mice were housed in
individual cages in a colony room with 20–25 ℃, a relative humidity of
40%, and were fed standard dry food twice per day.
Adult male mice weighing 18-22 g were anesthetized with an
intraperitoneal injection of pelltobarbitalum natricum. Dorsal skin was
shaved off a day before the experiment start, and the mice were randomly
divided into different groups (6 mice per group).
For tacrolimus short-term application, experimental groups were treated
with topical 0.03%, 0.1%, 0.3% tacrolimus prepared by glycerine
respectively twice a day, while glycerine as solvent was given to
control group. Scratching bouts were counted, skin and serum samples of
each treated and control mouse were collected at the end of 1 day. For
tacrolimus long-term application, experimental groups were treated with
topical 0.03% twice a day. C48/80 was used for subcutaneous injection
on day 7 and 11, scratching bouts were counted later and skin samples
were collected respectively. The experimental protocols involving mice
were approved by the Animal Ethics Committee at Xi’an Jiaotong
University, Xi’an, China (Permit Number: XJTU 2019-711).
Finally, serum and skin samples were further used to detect inflammatory
cytokines release and MrgprB2 mRNA expression. What’s more, H&E
staining and avidin staining were performed using collected skin
samples.