Unity inova 4.7 t small bore mri system

Mice were imaged at 8 weeks of age. Varian Unity/Inova 4.7 T small-bore MRI system (Varian, Inc., Palo Alto, CA; Small Animal Imaging Facility, University of Iowa) with an in-plane resolution of 0.13 × 0.25 mm² and 0.6 mm slice thickness was used. Coronal images were collected and lateral ventricle volume sizes were analyzed with ImageJ [8 (link)]. Quantification was carried out as previously described [46 (link)]. Fyn KO mice were divided by degree of hydrocephalus, with lateral ventricle volume of ≤0.2 units considered normal, 0.2 < x ≤ 2 units as moderate, and > 2 units as severe hydrocephalus. The lateral ventricle volume (LLV) cut-offs used to define these groups were based on the total movement assay, where significant differences in movement occurred between the groups as defined by these LLV cut-offs.

Mice were weighed once a week, beginning at weaning (4 weeks of age) until 25 weeks of age. Total fat mass and lean mass was determined by MRI under anesthesia (91 mg/kg ketamine and 9.1 mg/kg xylazine, i.p.) using a Varian Unity/Inova 4.7 T small-bore MRI system (Varian Inc.). The acquisition consisted of a T1-weighted fast spin-echo sequence (repetition time/echo time = 625/12 ms) with an in-plane resolution of 0.13 x 0.25 mm² and a slice thickness of 1 mm acquired in the axial and coronal planes. In addition, different fat depots and organs were dissected at death and weighed.
To measure food intake, mice were housed individually in regular cages and allowed to acclimate for at least 3 days prior to measurements of 24-hour food intake. In pair-feeding studies, each LRb^Cre/Bbs1^fl/fl animal was given the same amount of food consumed by sex-matched wild-type littermate the day before, beginning at weaning (4 weeks of age) until 15 or 25 weeks of age. Parallel groups of LRb^Cre/Bbs1^fl/fl mice were fed ad libitum. In the calorie restriction experiment, each LRb^Cre/Bbs1^fl/fl mouse was given 75–80% of the daily food intake of its control littermate, starting at 4 weeks until 14–16 weeks of age. Normal plasma leptin level of LRb^cre/Bbs1^fl/fl mice relative control littermates was used as an indication of successful normalization of body weight by calorie restriction.