Subarachnoid hemorrhage (SAH) model

SAH was achieved by pre-chiasmatic injection of blood withdrawn from the hearts of donor mice. Only male mice were used for the SAH treated mouse group as well as the donor mice.After induction of anesthesia, the head was fixed in a stereotactic frame. The anterior skull was exposed with a midline skin incision. 3.5 mm anterior to the bregma, a 0.8 mm burr hole was drilled into the skull with a caudal angle of 40°. A 27-G needle was advanced through the burr hole at a 40° angle until the base of the skull was reached, then 40 µl of whole blood was slowly injected and the needle left in place for 1 min to avoid backflow. After observing for overt bleeding, the skin was sutured, and animals were allowed to emerge from anesthesia under close supervision with body temperature maintenance using infrared light. The mice were treated with buprenorphine (50 µg/kg) three times a day for the first three days postoperatively. SAH was either induced at ZT2 or ZT12, which corresponds to the end of the 2nd and the 12th hour of the 12-hour light cycle. We chose ZT2 and ZT12 as the time points of SAH because these correspond to the nadir and peak within the circadian gene expression profile.