Vdr Conditional Knockout Mice in Stroke

Adult Vdr^f/f and Cx3cr1^CreER (#020940, Jackson Laboratory) mice of C57BL/6 background were mated to generate Vdr^f/fCx3cr1^CreER/+ mice. Vdr^f/f mice were kindly provided by Professor James C. Fleet from Purdue University. Mice were housed under specific pathogen-free conditions with sufficient food and water. Vitamin D and progesterone have been shown to play synergistic roles in relieving acute brain injury following cerebral ischemia [26 (link), 27 (link)]. Hence, to control the confounding impact of endogenous estrogen and progesterone, male adult animals were primarily included as the studied subjects for in vivo experiments. Male Vdr^f/fCx3cr1^CreER/+ mice were used as Vdr conditional knockout (Vdr-cKO) group, and age matched male Vdr^f/f mice were used as controls for in vivo experiments. The mice (8–10 weeks old) were given tamoxifen (75 mg/kg/d, Sigma) dissolved in corn oil intraperitoneally (i.p.) for five consecutive days 2 weeks before the middle cerebral artery occlusion (MCAO) procedure. Neonatal mice were used to obtain primary cells for in vitro experiments. Animal numbers for all experiments are indicated in the figure legends. All experimental protocols completely adhered to ARRIVE (Animal Research: Reporting of In Vivo Experiments) guidelines and were approved by the Animal Care and Use Committee of Xuanwu Hospital (AEEI-2021-295). Adhering to the ARRIVE guidelines, we here designated neurobehavioral functions and infarct volumes as the primary endpoints.