Transient MCAO

Surgical procedures were performed as described previously (4, 5). In brief, anesthesia was initiated by using 3% isoflurane (Abbott, Cham, Switzerland) in a mixture of O₂ (200 ml/min) and air (800 ml/min) and maintained with 1.5–2% isoflurane. Before the surgical procedure, a local analgesic (Lidocaine, 0.5%, 7 mg/kg) was administered subcutaneously. Temperature was controlled during the surgery and kept constant at 36.5 ± 0.5°C with a feedback-heating controlled pad system. For tMCAO, a midline neck incision was made and the left CCA was ligated proximal of the bifurcation of the ICA and ECA. Subsequently, the left ECA was isolated and ligated and a suture was placed around the ICA. A small incision was made in the CCA and an 11-mm long silicone monofilament (701956PK5Re; Doccol Corporation, USA) was introduced and advanced until it occluded the MCA and left in place for 60 min. A suture around the ICA secured the filament in position. Animals were transferred to a heated recovery box and allowed to wake up. Animals were reanaesthesized, the filament was withdrawn and the ICA was ligated. Sham operation involved surgical procedures, without occlusion of the MCA. After surgery, buprenorphine was administered as s.c. injection (Temgesic, 0.1 mg/kg body weight) and animals were placed in a heated recovery box for 2 h. Buprenorphine was then given twice s.c. every 6–8 h on the day of surgery and thereafter supplied via drinking water (1 mg/kg) for 36 h. Animals received softened chow in a petri dish placed on the floor of their cages to encourage eating.